South African services and equipment. (2024)

South African companies are aggressively attacking the export markets with technology and services that come from a strong background in the tough conditions of the domestic mining industry. Some of these suppliers are well-known internationally, others are newcomers to the world scene.

In 1993, AECI became an integral part of ICI's global explosives business, worth some $1,300 million annually. ICI took a 51% stake in AECI Explosives Ltd (AEL) and AEL became a full and equal member of ICI's international explosives business. This strengthened technology links with ICI Explosives and gained AEL further opportunities to export products to other parts of the world where ICI Explosives has an established presence and knowledge of the market. AEL's market is largely all of Africa excepting those countries bordering the Mediterranean.

Bulk Services is the vehicle through which AEL markets products and services to the open-pit mining sector. Currently, Bulk Services operates facilities in Ghana, Botswana and Zambia, aside from the South African home base. Some of these are also supplying bulk underground services.

Blast Consult is a group within AEL that creates and applies blasting science to practical mining problems, helping to increase production and lower overall costs. The services comprise design, measurement, analysis and problem solving. In broad terms this embraces: blast design consulting; determination of explosives properties; monitoring of explosives behaviour; high speed photography; surveys of blast profiles and fragmentation; computer blast modelling; and control and analysis of ground vibrations. The overall aim is to provide 'value added blasting'.

AEC Electronics is a wholly-owned subsidiary that develops and manufactures a comprehensive range of electronic instruments. Newly developed is the Intelligent Blast Initiation System (IBIS) which, AEC claims, offers greatly improved safety over other systems available worldwide. It also reports that blast reliability is far superior to other remotely fired blasting systems. It is extremely versatile, due to the modular design of the system. IBIS offers extremely high levels of pre- and post-blast information on a 24-hour basis.

It can be used in two different ways; to allow the capability to blast levels separately or to provide a full centralised blasting system. IBIS can be installed as a new system, or be connected up in place of existing electrical blasting systems with minimal new cabling.

The on-line Titoranalyser Controller (TAC) from Altech Mining accurately monitors and controls cyanide and pH levels in gold processing. The basic configuration monitors cyanide concentration in the plant and produces a report on the cyanide and pH levels determined. It also provides a simple user interface.

Installation of metering devices and valves allows for control of cyanide addition. Addition is based on actual cyanide concentration, required cyanide concentrations, pulp flow, pulp density and residence time. An optional external PC monitor with SCADA software can be linked to the analyser. This system incorporates an interface for displaying graphics and historical trends. A database for logging all events is provided by the SCADA package.

Born out of the nuclear industry, the Atomic Energy Corp. (AEC) has in recent years scored many successes in applying its proven technologies to solving mining problems. Recently introduced is its range of self-luminous signs designed to help save lives during mine emergencies. The compact safety signs, which can be mounted on side or foot walls, can be used to mark routes to refuge stations underground. AEC's Lumitec Division is also developing a self-luminous light source which, when worn by a miner, will allow that person to be easily identified during rescue operations.

Another recent product, which has shown remarkable results in a series of tests, is the Flosep pre-filter. This high efficiency, self-cleaning unit for use on mining machinery has been shown to achieve 96-97% efficiency in reducing dust ingress and prolonging filter life by up to ten times. Vortex tube technology has been applied to a broad range of dust removal problems by the Flosep Division. These include filtration on draglines and mining shovels, the reduction of high dust loads near continuous miners, the cleaning of ventilation air, dust extraction from crushers and conveyor systems and the cleaning of air entering compressors and other machinery such as turbines.

Turbine and compressor refurbishment products are the area of specialisation of the Turbo Systems Technology Division, while advanced systems for vibration monitoring on critical machinery, like compressors, are supplied by the Advanced Monitoring Systems Division.

Turbo Systems Technology manufactures turbo machinery-related products such as steam turbine blades, discs, diaphragms, compressor rotors and shafts, impellers and diffusers. It also specialises in adapting cooling compressors as part of the CFC replacement programme.

Products that are gaining rapid recognition are the Kangela range of on-line and portable ash monitors. Designed to provide coal mines with better yields, Kangela was developed by the Industrial Isotopes Division, which also offers a broad range of radioisotope-based diagnostic services. These include the use of radioisotopes and radiation techniques for on-line determination of metal concentrations, flow rate measurements, thickness and dispersion determinations and ventilation studies.

A wide range of investigations aimed at the optimisation of process design and control have been undertaken recently. These include residence time measurements at a gold plant, a study of the behaviour of solids in a gold extraction column and leak testing of the vacuum systems of the filter plants at three gold mines.

Other mining-related services offered by AEC include specialised fabrication, high technology engineering services and the manufacture of mechanical components.

Barlows is the Caterpillar dealer for a large part of Southern Africa. In 1965, it was licensed to become the first Cat manufacturer outside the U.S. and today produces up to 1,000 machines and units a year, including wheel loaders, graders, articulated haulers, underground mine graders and LHDs, using Cat components.

The LHD is the Wright HD 256 with a maximum payload of 5 t and a 2.5 [m.sup.3] capacity bucket. This 15.7 t machine develops gross power of 111 kW. The Wright 120G LP is a low profile motor grader which has been sold to mines all round the world, including one working in Arctic Norway. The 120G LP features a 3,011 mm long mouldboard, which is 610 mm high and 22 mm thick. A flameproofed version is available for coal mining.

In surface mining, Barlows offers the 'Stealth' bucket. This new development is the result of extensive research into the wear patterns of Caterpillar 992 buckets operating under very aggressive conditions at the Orapa and Letlhakane diamond mines in Botswana. The work has led to bucket life expectancies of five times their original life spans. The Stealth bucket is now being marketed worldwide.

Bateman Equipment manufactures and supplies flotation cells, thickeners, filters, classifiers, pumps, ore sorters, magnetic separators, vibratory equipment and mixers. Last year saw the Bateman Group celebrate 75 years in business and over the period it has grown from a one-man enterprise into a worldwide equipment supplier.

One of the unique designs is its patented flotation mechanism that has already gained international acceptance for versatility in roughing and cleaning flotation circuits. The versatility and flexibility of the new design provides for maximum customisation to suit individual client process requirements. A thorough understanding of the hydrodynamic and metallurgical performance of the new equipment enables Bateman to 'tune' the configuration of the mechanism, such as rotor diameter, speed and power, to the particular application required by the client.

Each application is assessed to ensure that the equipment operates to exact performance requirements, particularly with regard to three important criteria. Firstly the maintenance of uniform pulp suspension through efficient pumping levels, secondly, the dispersion of sufficiently high volumes of air to achieve optimum flotation efficiency and thirdly, the production of appropriate bubble size for the particular metallurgical application.

The open topped impeller design considerably enhances pumping capacity and efficiently disperses high volumes of air, thus achieving superior solids suspension, even for dense particles, at exceptionally low power consumption levels. In comparison, impellers with internal air inducement need to be operated at higher speeds to achieve solids suspension at high air additions.

In most applications, small bubble size provides metallurgical benefits and, where small bubble size is critical, the new mechanism is con figured to produce high shear at the rotor tips. On the other hand, in cases where very heavy duty applications are required, the suitability of the system for ultra coarse materials processing has been proven. For instance, the installation last year at Ancuabe graphite mine in Mozambique required a very heavy duty flotation application, capable of recovering graphite flakes up to 2 mm in size. Here, at high graphite concentration grades, recoveries of some 98% are being achieved.

One of the major advantages of the equipment is the ability to start-up easily under load as the stator hood protects the rotor from settling solids during shut-down and prevents the rotor from becoming bogged down. The hydrodynamic shape and design depth of the tank go a long way towards eliminating sanding and dead zones. The deeper quiescent zone improves mineral selection and concentrate grade without affecting mineral recovery rates. In addition, the hydrodynamic shape provides added strength, enabling the production of deeper tanks that require less floor space.

Maintenance costs are also generally low because the overhung rotor-stator mechanism facilitates quick removal and replacement of parts without the need to empty the tank.

Over the years Bateman has installed over 5,000 flotation cells worldwide and consequent to this broad-based experience, the Bateman flotation cell has evolved to satisfy the most rigorous demands of the flotation market.

Another new machine is the Circular Motion Inclined Screen. Through the use of twin flange-mounted vibrator motors mounted at the centre of gravity of the screen, a circular motion is produced with an equal vertical and horizontal component. This, combined with an inclination of 15-20 ° results in higher velocity and equal motion vectors over the full screen surface. The higher velocity produces excellent stratification and efficient screening over the screen length, lower bed depths at the discharge end and minimal pegging due to the equal vertical and horizontal components of circular movement.

ISO 9001 status now applies to Bateman's trackless mining division, Bateman Mining Equipment, and mine prop systems company, Elbroc Strata Control. "This is the culmination of a three year programme in which procedures were written and standards set for our trackless mining equipment," says Glen Zille, managing director of Bateman Mining Equipment.

"With the re-emergence of South Africa into the international arena it is essential that SA manufactured products are able to compete both on price and quality with the rest of the world. The SABS ISO 9001 listing is internationally recognised and provides our customers with a considerable comfort factor."

Bell Equipment is one of the great successes among South African manufacturers and now boasts mining sales of some 30% of its worldwide market. Its strong markets are in Southern and East Africa, with a growing reputation in West Africa. It is also very active in Australia and South America. In South Africa it has in excess of 2,000 machines working in mines, with all the major mining houses and with contractors. Over 200 of these units are working underground. Terry Gillham, the marketing director of mining, reports that there is now a trend among the South African mining houses not to purchase the smaller earth-moving equipment typical of the Bell line but to contract out work such as rehabilitation and disposal of discards. Consequently the company is experiencing a decline in mining house sales with a commensurate increase in purchasing from contractors. The mining houses thus benefit from knowing a fixed cost for these operations. A similar trend is apparent in Ghana, Terry Gillham reports, where contractors are very active in the open pit gold mining sector, among others.

The Bell product line includes wheel loaders, articulated dump trucks (ADTs), including low-profile haulers for underground, and its three-wheeled scaler unit which has proven very successful. Bell's rough terrain forklifts are popular on the gold mines for use in materials handling on the surface, as are the wheel loaders.

A recent significant underground sale has been the purchase by BHP of three B25L 4x4 low-profile, 25 t capacity articulated haulers for the Hartley platinum mine in Zimbabwe. GFC will lease these units for the development of the decline access and then the mining operator, BHP, will take them over as part of the mining fleet. Similarly there have been recent sales of both the B40 and B30L (a low-profile 4x4 with a 30 t capacity) to gold mining contractors in Western Australia where a number of open-pit mines are developing declines to go underground. Terry Gillham sees this as a market with great potential.

Back on surface, special Bell ADTs equipped as water tankers (maximum capacity 35,000 litres on a B40), diesel bowsers and flat-deck service trucks are gaining in popularity for service support in open pits such as Orapa and Jwaneng in Botswana and New Vaal Colliery in South Africa.

Recent new products launched by Bell include the B16B ADT. This is an unusual machine in that it is a 6x2, with front-wheel drive and two trailing axles. Pulled by the B17 tractor, the B16B thus offers a cheap alternative to more traditional ADTs, providing a machine that is very suitable for long flat hauls. The 3.5 [m.sup.3] L2206 wheel loader is another recent new product from the company.

Bell has operations in North and South America, South East Asia and Australasia, apart from its growing African network. There it now has offices in Abidjan (Ivory Coast), Nairobi (Kenya), Lusaka (Zambia) and Harare (Zimbabwe). For product support it has fixed-wing aircraft based in Harare and in Tanzania, where it has recently sold equipment to Samax's new graphite mine.

Interest for its safety products from as far afield as Australia, India and Canada is reported by Coal Control. This is mainly for its Moses guidance system which provides a clearly indicated route to refuge bays in the event of an underground accident. Emitting both an audio and light signal, Moses leads miners along an escape route during a power failure or when visibility is reduced due to dust and smoke.

Coherent Laser Systems' Lasermeter has many applications in materials handling such as; ore level control in crusher feed, positioning of conveyor trippers, ore pass blockage detection, silo level control and height control of stackers.

The Council for Geoscience, the successor to the Geological Survey of South Africa, was established in November 1993. In addition to projects undertaken within the borders of South Africa, the Council is also active in various projects in other countries. Metallogenic and geological maps on various scales have been and are being produced for various countries. Mineral resources studies are underway in various African countries and engineering geological studies have been undertaken. The laboratory is very active in rendering assistance to foreign geological surveys and universities.

It is a primary function of the Council to promote the mining industry by stimulating exploration for, and exploitation of, minerals and by supporting the growth of secondary industries related to mining. Its main activities are in economic and regional geology; environmental, engineering and marine geoscience; geophysics; mineralogy, petrology and geochemistry; data processing and cartography; and information services.

Davy International has been awarded contracts for the design and supply of three modular chrome beneficiation plants for three separate mines in Zimbabwe. The beneficiated chrome will be used as feedstock for the Zimbabwe Alloys ferrochrome smelters. These dense medium plants are being designed in-house by Davy in South Africa.

Also in Zimbabwe, the company is to design, supply and supervise the construction and commissioning of a 13.5 MVA circular matte furnace for the smelting of PGMs for BHP Zimbabwe's Hartley project. Design and engineering services will be provided by Davy's partner in Southern Africa Elkem Technology, for which it is the representative in the region. A feature of the furnace package will be the 'state-of-the-art' modular electrodes. These, being more compact in design and more efficient in operation result in savings in capital cost and power consumption.

A third project is for the design and supply of three modular electrode holders (again using Elkem Technology's design) for the fourth ferrochrome furnace for CCT's smelting operation in Rustenburg, South Africa.

DeBeers Industrial Diamond Division (Debid) is closely involved in the diverse applications of both synthesised and natural industrial diamond products. Debid also develops new and improved diamond recovery technology and equipment through the Mineral Processing Division (MPD) of the De Beers Diamond Research Laboratory (DRL).

MPD has continued to provide support in detection, crushing and liberation techniques, X-ray recovery, water treatment and dense phase disposal equipment and in ore sampling and auditing. MPD is also involved with De Beers Marine and the development of innovations used in the ocean bed recovery of offshore diamonds. Debmarine is the only company able to exploit marine deposits at depths up to 200 m. Each vessel in the fleet constitutes a floating diamond mine with a diamond recovery plant on board.

Diamond technology from the DRL has also found application in the South African gold mines of Anglo American where mechanisation has long been a desire that is taking some time to achieve, but diamond wire sawing is showing strong promise in a project designed to introduce non-explosive selective mining of the gold reef. This reduces waste material transportation, processing and mining costs and gives a significant safety dividend important in deep level mining operations. The Technical Development services of Anglo is well advanced in work on this and in related diamond sawblade technology.

Anglo American will soon have 17 double wire cutting machines, valued at some R8.5 million, on its mines. Five of these are still being manufactured, five are at the Vaal Reefs mining complex, six are at various Free State mines and the last is operating in a chrome mine in Zimbabwe. Diamond wire cutting works best in narrow reefs ranging between 50 and 500 mm. The achievable cutting speed ranges from 15 to 35 m/s, depending on rock conditions. However, much work is still required to fully determine the technique's economic value.

Debid industrial diamond grits and polycrystalline drill bit elements are widely used in drilling, and development of these products continues.

The industrial use on a large scale of advanced membrane-based water and effluent filtering equipment is now well established through Debex, a subsidiary of Debid which is also involved in engineering, rubber linings, wear resistant ceramics and sophisticated electronic equipment for mining. It recently supplied a new desalination plant to the Orapa mine in Botswana. The [C.sup.2] meter, developed by Mintek and manufactured by Debex, uses the attenuation of a high frequency ultrasound signal to establish the carbon in a CIP or CIL tank.

Delkor has been exporting metallurgical process equipment for some 15 years. Typical export projects have included belt filters for the recovery of gold and copper in Chile, and other belt filter deliveries to Zambia, Zaire and Israel. Delkor is a world leader in this technology with the largest installations on most continents. Its Linear Screens, mainly for CIP plants, have been exported to South America, North Africa, Russia and South East Asia. Delkor Linear Screens are now locally manufactured in North and South America, Europe, Australia and South Africa.

Both conventional and high rate Delkor thickeners have been exported to Chile, Ghana, Zambia and Zimbabwe. Also in Zambia, the Automatic Delkor Filter Press is being used extensively for copper concentrate and underground sludges.

Jigging plant for alluvial gold and ferro alloys are in operation in Venezuela, Mozambique and Zimbabwe.

Locally, Delkor is at the leading edge of developing process technology. The joint development by Anglo American and Delkor of the Linear Screen in 1985 revolutionised tramp screening in the gold industry. Today, few Western gold plants do not use this technology. More than 400 units have been built, ranging in size from 0.5 to 30 [m.sup.2].

Uses of the unit have extended beyond tramp removal to beach sand classification and effluent dewatering. Furthermore, joint research is continuing with Anglo and the Vaal Reefs mining complex (where the prototype is still operating) investigating the use of the Delkor Linear Screen for classification in gold ore milling. Preliminary results are very encouraging.

A recent joint development with Roxon is making significant advance in the screening of wet-sticky coal in sizes down to 4 mm. The Delkor/Roxon Elliptical Roller Screen is now employed at four South African coal preparation plants, with impressive results in efficiency, throughput and operating costs reported.

The new Delkor 'Jet Vac' is designed to re-slurry hard, sticky and compacted underground gold mine fines, and to suck this valuable material into a fines handling system which can include stone screening, water recovery and dewatering of the fines to make it into a hoistable form.

Denel was primarily known for its military products, but since its inception in April 1992 a wide range of industrial products have become available to Denel Mining from its manufacturing divisions. These divisions include Somchem (cable bridges and pipes), PMP (pipe clamps, coal picks and drill bits), Eloptro (alignment lasers, drill control systems and mine security systems), Swartklip (secondary breaking devices and non-explosive rock breaking), LIW (hydraulic rock drill), Dendustri (slurry clearance systems), Ergotek (ergonomic consultation), Naschem (oxygen generator, demolition charges, orepass clearing mechanisms, pumps and turnkey plant engineering).

The products aimed at primary and secondary rock breaking and orepass clearance are based on metallurgical and explosive technologies previously used in the military industry.

Swartklip's Boulder Buster is a product used in both civil and mining operations to break rock where the close proximity of buildings or equipment prohibit the use of normal explosives. It uses a standard shotgun shell and creates water/gas pressure in a drill-hole to split open rock.

To date, PMP's ProPic has had great success with coal mines achieving greater pick life, while gold mines have benefited from longer drilling life using the cold formed ProBit body.

Naschem's Survivair is attracting considerable international interest. Originally designed for use in submarines, this oxygen candle is totally self-sufficient and maintenance-free. Pulling a pin sets off a chemical process that releases 2,900 litres of pure oxygen, or 15,000 litres of breathable air within 35 minutes. Each Survivair contains four oxygen candles, housed in a stainless steel container. When activated, each candle will provide enough breathable air to keep ten people comfortable for up to 32 hours. It has been approved as intrinsically safe for use in all underground mines by South Africa's Government Mining Engineer.

Eloptro's ACBIT is a head-up display unit which can be retrofitted to jumbos to visually indicate to the operator where holes are to be drilled, without the need to mark the face.

The Smith AP50 is a high performance, low maintenance new generation hydraulic drifter with a very low part count that has been developed by LIW for Smith Underground Equipment.

Engineering design, project management and servicing are all provided by Dorbyl Heavy Engineering's (DHE) Products Division for the mining, metallurgical and materials handling sectors. Its strengths are in mine hoisting, grinding mills, converters, ladles, transfer cars, tipplers and kilns.

DHE's range of hoist designs includes the three major types: friction or koepe hoists; drum hoists, both single and double drum; and multi-rope drum hoists (Blair Multi rope). Operating depths cover the full spectrum from 250 to 2,500 m, with payloads of up to 28 t for mineral, material and man hoisting. DHE has designed and manufactured some 290 hoists of various types and sizes. Of the 248 hoists designed and manufactured in the past 30 years, about 90% have been for shaft systems in excess of 1,000 m deep.

Mill diameters have increased in steps of some 0.6 m up to today's biggest trunnion mills of 5 m diameter by 10.7 m long and the largest slipper bearing units of 5.8 m diameter by 8.5 m long, with conceptual designs up to 11 m diameter. To date DHE has designed and manufactured over 600 trunnion mills and about 30 slipper bearing mills for the mining industry.

Dowding Reynard and Assocs (DRA) manufactures modular dense media separation (DMS) plants. Important features include: ease of operation with ideal operator access; easy maintenance, with access to all individual items of equipment for on- or off-site maintenance; designed to maximise water recirculation.

Such plants are trial erected by DRA in South Africa. They are then packed into containers for transport to site for re-erection and commissioning.

Diamond plants exported in 1993 included a 12 t/h plant to Canada and a 30 t/h unit to Zimbabwe. Orders last year included one for a 100 t/h plant for the Williamson diamond mine in Tanzania and, what DRA believes is probably the world's largest modular DMS for diamond recovery, a 150 t/h plant for CDM in Namibia.

DRA also offers worldwide services in process plant design, project management and turnkey projects. It is particularly well experienced in supplying the platinum mining industry of Southern Africa with such services.

Dymot Engineering has been involved in conveyor tensioning for over 15 years. During this period it has evolved a philosophy of tension control using slow winches and continuous tension monitoring. The main considerations in the development of its automatic belt tensioning system were: cost effectiveness; long-term reliability; easy maintenance and simple concept; flexibility for the client; and minimising belt stresses.

South Africa's leading small submersible pump manufacturer, Emelpee, has a range of products claimed to be unique, or offering unique features. The range includes submersibles such as a battery-operated drainage pump; a cast stainless steel solids handling pump; and a vortex pump for abrasive solids.

The SV series stainless steel pump is designed for corrosive applications and those beyond the scope of normal pumps. It is ideal for effluent, sump drainage and transfer of chemicals. Made in 316 stainless steel, one of the most corrosion-resistant materials available, it is offered in a range of impeller sizes and passes solids up to 40 mm.

The KVC series easily withstands liquids containing highly abrasive solids. This is due to its 12% chrome cast iron pumping end, hardened to 60 Rockwell. It features a recessed impeller for free passage up to discharge size.

Emelpee has developed a range of fully-portable battery-powered submersibles offering five distinctive features. Known as the D-series, they operate off standard 12 and 24 V truck or pick-up batteries. Designed specifically to handle solids, they utilise power from the battery more economically, use existing and readily available Emelpee parts and come with several standard variations and pumping ends. These include: vortex-type standard version; a strainer type for cleaner water but capable of higher heads than the vortex type; a range made entirely of 316 stainless steel for highly corrosive liquids/effluents and a range with 12% chrome cast iron for abrasive materials; and a fully-automatic version utilising a float switch as its automatic control system. The KVC series utilises important common components from other proven Emelpee pumps and comes in sizes 40 and 50 mm with motors from 0.25-0.75 kW. Also offered is a mini-sized flameproof pump and an air-driven solids handling pump for higher heads.

Shuttlecars, compressed air loaders and flameproof alternators are the main export products of EMM Mining Systems, the leading mining machinery manufacturer in South Africa. The company is also very experienced and successful in the manufacture and supply of LHDs to the domestic market.

EMM has recently adopted an aggressive stance on exports having opened a branch office in Zimbabwe and participated in major exhibitions in the U.K. and Chile last year. There is continued interest in the shuttlecar line from a potash mine in the U.K. and a unit is on trial in Australia currently.

Designed and engineered completely by EMM, the shuttle-car range was introduced in 1992. The company has already sold some 20 units and last year obtained a 35% share of the South African market. The shuttlecar range comprises 10, 12, 14, 16, 20 and 24 [m.sup.3] capacity machines able to work under roof heights of 1.5 m and upward. The unique modular design of these shuttlecars facilitates exceptional manufacturing flexibility, minimal maintenance and reduced parts inventories for the mines on which they operate.

Major innovative design criteria were applied to all shuttlecar components - including the body, steering system, DC drive and motors, wheel units, conveyor gear box, hydraulics, brakes and cable reel arrangement. The DC drive features automatic load sharing which extends motor life, regenerative braking, built-in diagnostics and separately excited motor fields which enable the shuttlecar to inch into position. A moveable rocker ring on the DC motor allows easy access to brushes. The drive unit has been engineered for soft acceleration and deceleration. This eliminates shock to the drive train and increases the lifespan of components. It also allows the shuttlecar's direction of travel to be changed while in motion without causing damage to drivetrain components.

In the company's past, as Eimco Mining Machinery, the first machine to be introduced to South African mines, in the 1930s, was the Eimco air loader, which is still in demand today. There are some 3,000 Eimco air-powered units at work in the mines of Southern Africa. The EMM 28 AL air loader is the most modern version and is capable of loading 2 [m.sup.3]/min. These rugged, dependable machines have established a reputation for productivity, while at the same time being simple to operate and easy to maintain. Beyond Southern Africa, a good market for these air loaders is expected to be South America.

The newly developed flame-proof alternator for trackless equipment, together with the correct globe selection, significantly improves lighting and also provides consistent lighting throughout the speed range of the host underground vehicle, ensuring unimpaired vision for the operator.

South Africa's first locally-manufactured flameproof diesel generator set for underground mining, the James Flameproof Generator, has passed stringent surface testing at Sascoal Engineering, at the request of the Secunda coal mine. It also enjoyed an enthusiastic reception at the Electra Mining last September. "Had the unit been in production at the time of the exhibition we could have sold at least ten units," says Arthur Webb, sales director of EMTS, one of three companies in the consortium producing the James generator.

The other two enterprises are Power House, which will be supplying partially flameproofed Atlantis diesel engines (Atlantis is South Africa's premier diesel engine manufacturer) and Elgin Engineering which will complete the flameproofing. Besides manufacturing an approved alternator, with a multi-step voltage facility, EMTS will also make the trailer chassis which houses the generating unit.

This generator was developed to serve the industry's identified need to recover electrically powered continuous mining machines in the event of a power failure. It has been well received for its safety contribution and the increased productivity benefits it offers. According to Dave Warren of Power House: "The flame-proof generator assists productivity by obviating the need to disconnect and then reconnect a series of cables when moving electrically operated machinery such as shuttle cars over distances substantially longer than their cable reach. Instead they can be plugged into the generator set which is then towed behind the shuttle car or any other piece of machinery during relocation."

Each unit will have to be custom-made because requirements and specifications vary from mine to mine. A second prototype is being tested on continuous mining machines at Secunda. International enquiries for the product have already been received from the U.K., Italy and the Czech Republic.

Power House

Atlantis Diesel Engines

EMTS

Elgin Engineering

Computer Aided Blasting from Expert Explosives combines the accuracy of electronic detonator timing with the flexibility of computer aided design. Using Expert Explosives' Blast Commander software, users are able to design, edit and simulate a blast on a PC. Using the powerful graphics, simply draw the hole and enter the delay, from 1 to 15,000 milliseconds.

The design is downloaded into the Blast Programmer, a robust field unit which checks and assigns the unique timing pattern to the electronic detonators while they are down the hole. Any changes to the timing pattern can be made right up until the shot is scheduled to go off, by simply changing the timing on the display.

The internal energy storage ensures that all detonators are cooking in the hole before the first hole goes off. Any chance of cutoffs is eliminated.

This ability to control timing to millisecond accuracy allows the blaster to harness the inter-hole shock waves that will lead to improved fragmentation, reduce powder factors and change muckpile profiles to complement mining equipment. It allows dangerous vibration frequencies to be avoided and amplitudes reduced. Computer Aided Blasting transcends the advantages of accurate electronic detonators by providing the flexibility of computer control.

Its benefits to productivity have already been proven in open pit mining. Kleinkopje coal mine in South Africa is one of the first users of the system, for blasting overburden, and a significant increase in dragline productivity has been the result.

Biox bacteriological technology, developed and patented by Gencor, uses bacteria to oxidise sulphides and thereby release the gold in refractory ores. Biox is the most economic and environmentally sensitive way of treating such ores, according to Gencor. The technology will be important in the newly-formed joint venture between Lonrho and Gencor to develop gold mines in the CIS.

Lonrho associate Ashanti's Sansu gold mine is currently the largest Biox user (720 t/d) and Lonrho's winning of the Amantaytau gold project in Uzbekistan was in large part due to its access to the technology. Discussions with the Uzbek State Committee on Geology are well advanced for its Ingichki establishment to be a centre for testing the suitability of ores for the Biox process.

The first commercial Biox plant was commissioned in 1986 at the Fairview mine in South Africa. By 1991 Biox was treating the total concentrate production of some 35 t/d. The replacement of the mine's Edwards roasters by the Biox process contributed tremendously to solving the environmental problems of sulphur dioxide and arsenic trioxide pollution.

Other operations now using Biox include Sao Bento in Brazil (150 t/d), and Harbour Lights (40 t/d) and Wiluna (115 t/d) in Western Australia.

Grinaker System Technologies (GST) is a leader in mining electronics, particularly in communications and control, with products that include portable radios, mine dispatch systems, shaft monitor systems, conveyer monitoring and control, telemetry stations and environmental sensors.

The SC2000 is a new generation, portable, inductive radio for use underground. It is intrinsically safe and special emphasis has been placed on reliability by using surface mount technology and a minimum of connectors and cables. It weighs just 1 kg, but its performance has been enhanced by the use of a 3 W transmitter output and a fully automatic bandolier tuner.

Both this and the older SC1000 use two antenna systems, Long Wire Antenna (LWA) and the Distribution Antenna System (DAS). The principle of both systems is that when a current is passed through a conductor, it induces a magnetic field around the conductor. This field is at 90 ° to the conductor in circles. If this magnetic field cuts through another conductor at 90 ° it will cause a current to flow in that conductor - thus creating a reverse effect.

This is exactly what is done with the underground radio system; the radio base station transmits into the antenna, which sends current down the wire inducing a magnetic field around the wire. This field induces a signal into other cables running parallel to it which also produces a magnetic field. This magnetic field cuts through the antenna of the portable radio at 90 °, inducing a signal in the antenna which is received by the radio. This coupling of the signal into other existing cables enables one to get coverage in some areas where there is not necessarily any antenna wire.

GST has also recently developed an underground vehicle tracking system. This, in addition to vehicle tracking, provides a database, report generation and some process control. The first of these systems has been purchased by Ingwe's developing Khutala coal mine; a room and pillar operation using continuous miners.

Another new product is the Rescue Router by which miners underground can follow up to 99 audio-visual units in one system to guide them to safety. Both audio and visual signals are provided to ensure that the safe path is clear even in smoky atmospheres.

Haggie Rand is one of the five major companies in the world supplying steel wire rope. Following the lifting of sanctions, it is just re-establishing itself in the U.S. with a newly opened sales and technical support office in Denver, but is also widely represented around the rest of the world. In Johannesburg, Haggie Rand operates one of the world's largest integrated wire mills and roperies.

It has continuously developed its steel wire rope products and technology to keep abreast of the unique shaft and opencast mine rope needs of the South African industry. Underground gold mining at depths exceeding 3,000 m and requiring single shaft hoisting depths of around 2,300 m, needs steel wire ropes of specialised design and construction to overcome the problem of an economic weight:strength ratio and meet the stringent safety requirements of the industry. Similarly, the achievement of optimum service life from dragline hoisting and shovel ropes is of prime importance in the opencast mines.

Haggie Rand specialises in the design and manufacture of Triangular strand hoist ropes, typically 50 mm in diameter that wind at speeds of 15 m/s, and tough, durable Non Spin shaft sinking ropes designed to withstand the stresses of these operations. The benefits of ropes designed for deep level mining are applied to shorter lengths to improve service life.

The company's highly certified testing laboratory enables it to test, on-site, mine hoisting ropes with a breaking force of up to 2,600 kN.

In Australia, the company's 50 mm compact design shovel ropes have achieved twice the service life of other products while 127 mm dragline ropes are reported to be setting new records in their field.

Huddy manufactures diamond surface-set and impregnated core drilling bits and crowns, thin-wall diamond tipped bits and designs special diamond tools. The company also supplies drill rods, casings, core barrels and ancillary drilling equipment as well as manufacturing tungsten carbide blasthole bits.

The economic growth and stability of Africa will largely depend on the exploitation of mineral deposits. "This I'm sure is a common feeling amongst international industrialists," says Vic King, joint managing director of Inspectorate M&L. "But," he warns "the level of success of the mining projects will be largely due to the accuracy of the initial exploration work and the recommendations made there from."

Inspectorate M&L is the wholly-owned South African subsidiary of the international laboratory, sampling, inspection and testing giant, Inspectorate. The company, rated locally the leading independent commercial laboratory, has earned its reputation having been involved in South Africa for over 60 years and the geochemical analytical service available to the mining community enjoys an international reputation.

Inspectorate M&L has been involved in many of the most successful mineral and mining explorations, which include coal, chrome, iron, titanium, gold, the PGMs, andalusite, kimberlite, copper, lead and bauxite.

Some of the techniques applied to these projects are the study of changes in concentration of certain elements in surface soil, rock or stream sediment, or in groundwaters and plants. Large numbers of samples are analysed by rapid low-cost, but reliable, methods which often provide a very low level of detection. The elements determined may be either those of direct interest, or 'pathfinders', such as arsenic or fluorine sometimes associated with mineralisation. The very powerful and valuable technique of X-ray fluorescence analysis is used to determine potential, from trace levels to major percentages of elements in deposits.

Inspectorate M&L can provide analytical expertise from the initial exploration work through to plant acceptance trials and final contracts for the sale of product to the consumer.

Iscor coming from a background of, currently, ten operational mines, ranging from very large coal and iron ore open pits to medium-sized underground coal mines to relatively small dolomite and quartzite pits, offers a variety of mining and beneficiation consulting and support services, beginning with mine planning and surveying. Iscor also has considerable experience in the use of innovative mining methods such as in-pit crushing and haul truck trolley assist, both of which technologies are employed at its large Sishen iron ore and Grootegeluk coal mines. The company also offers a high level environmental management service and has expertise in iron ore, coal and non-ferrous metal beneficiation.

Iscor operates five integrated steelworks with a combined capacity of 8 Mt/y of liquid steel. It offers consulting and support services in coal briquetting, improvement of coal strength, reducing the use of good co*king coal and the effective use of low-grade and non-co*king coals.

Further downstream in the steel process, Iscor operates the world's first commercial Corex plant in Pretoria. It also has the world's largest coal-based direct reduction plant at its Vanderbijl-park works. Iscor has already started the training of operations and maintenance personnel for future operators of Corex plants.

It is also in the process of converting its Pretoria works into a stainless steel plant and in constructing a 1.32 Mt hot rolled steel coil plant at Saldanha.

Kwikmark offers a line of alignment systems including the Kwikline Mining Laser which was developed specifically for underground coal mining. It is a self-contained unit, designed to hang from brackets welded to the body, which provides a direction line for mining a heading.

Kwikangle is a versatile instrument for measuring vertical and horizontal angles plus any levelling likely to be required in the daily routine of underground mining. Kwikspot, a drill pattern alignment projector, uses a metal gradicule which has been precision drilled. It is suitable for drivages ranging from 10 to 40 [m.sup.2].

LTA has various divisions active in mining. Autecon covers the areas of instrumentation and electrical contracting, process control sales and associated services, engineering and project management for turnkey projects.

LTA Process Engineering is a leader in process technology engineering and project management. It has signed an agreement with Mintek to develop the MINRIP resin-in-pulp gold recovery technique. This process uses Mink, a gold-selective strong-base resin which is reported to yield higher gold loadings and to load faster than carbon.

Contracting and engineering services offered by LTA Civil & Earthworks include coal and metal mine construction, surface mine operation, coal processing plants, engineering for transport and infrastructure, and environmental remediation.

Gencor, CSIR Mining Technology (Miningtek) and M&M Systems have entered into an agreement to develop Prism, a digital seismic monitoring system. Miningtek, through its roots as the Chamber of Mines Research Organisation, has been involved for over 20 years in seismic research and developed Prism's successful predecessor, the Portable Seismic System (PSS). M&M is already internationally known as the manufacturer of PSS and has substantial experience in electronic systems.

Like PSS, Prism is designed as an integrated off-the-shelf system and runs on a standard 486 PC. It can be installed in under a week and once in place can be operated by mine personnel after a short training course. Thus, mines need not employ full-time seismologists but have the option of using consultants to assist with seismic interpretation. Prism can also be moved by mine personnel to new sites as excavations advance. In short it is a multi-task system capable of high-speed processing in real time of all seismic waveforms recorded by underground sensors. This data is directly transmitted over standard telephone cables to a central 486 PC on surface. The new Prism software can automatically display data received on a 3-D mine plan enabling it to be immediately understood even by non-specialists. The software is Windows-based for ease of use and allows for rapid access and analysis of seismic activity.

The Buffalo R5AV is a fully automatic roofbolter from McCarthy Mine Machinery. Designed to work with continuous miners, McCarthy claims the machine "can virtually double the number of roofbolts inserted per shift with one operator only, working from under a supported roof." The company also reports that within one year the accumulated cost of bolting with the Buffalo R5AV breaks even compared with manual bolting, and thereafter becomes cheaper.

Metallurgical Design & Management (MDM) is a process engineering and project management company specialising in the design, supply, construction and commissioning of processing plants. The company focuses particularly on medium-sized mining operations, with projects completed for mines with treatment rates ranging from 6,000 to 100,000 t/month, covering many minerals including coal, diamonds, precious metals, base metals and industrial minerals.

MDM has supplied a 30,000 t/month diamond recovery plant to Rovic Diamond Mines in the Orange Free State, a 60,000 t/month andalusite plant to Hoogenoeg mine in northern Transvaal and a 6,000 t/month zinc-copper concentrator to Maranda mine, also in the northern Transvaal. Building on the success of these plants, MDM ventured into exports and completed the 10,000 t/month gold recovery plant at Monarch mine in Francistown, Botswana, followed by the fully-mobile trailer/container 12,000 t/month gold plant for Twiga Mining near Nzega in Tanzania. Further domestic deliveries include a 100,000 t/month coal washer to Annandale coal mine, northern Natal, and a gold elution plant supplied to Primrose gold mine, Germiston.

Most recently, MDM completed the 30,000 t/month gem-stone and graphite recovery plant for Graphtan at Merelani, Tanzania and the 30,000 t/month gold tallings retreatment plant for Prestea Sankofa under construction in Ghana.

MDM offers full feasibility services including geology, mining, infrastructure, metallurgical testing and consultancy. Recently established is a Customer Services Division offering procurement services for spares and consumables to mining operations in Africa: a recent contract is to rehabilitate and manage the Mchenga coal mine in Malawi.

Metprotech is the developer and owner of a proprietary fine milling technology which offers significant benefits. It allows for the efficient milling of large quantities of material to extremely fine sizes. The milling action is such that the milled particles have relatively large surface area.

In extractive applications, the Metprotech technology offers low-cost methods for the recovery of gold from refractory ores. It also offers innovative alternatives to conventional base metals recovery processes.

The company offers the Metprotech Ultra-Fine Mills (UFM) technology and market support from offices in South Africa and Australia.

South Africa's national minerals research organisation, Mintek, founded in 1934 to assist the mining industry to operate more effectively and profitably, has achieved international recognition for its work. Mintek works closely with industry and with university research groups to examine, develop and implement new and improved technologies, and in particular to encourage the manufacture of value-added mineral products. Mintek's activities are covered in detail in the first section of this supplement.

Considerable success has been achieved by Moh-9 Weartech with its alumina ceramic impellers for slurry pump applications. Ceramic impellers can replace conventional impellers manufactured from steel, rubber, Ni-Hard, etc., giving longer operating life, more constant yield and higher resistance to wear and chemical attack, the company reports.

A recent example is a 270 mm diameter alumina ceramic impeller made for a gold mine.

In this particular application, the pump operates at about 800 rpm, yielding a pressure of 100 kPa. MOH-9 also makes impellers which can operate at 2,900 rpm, producing a head of 150 m through a 76 mm outlet pipe.

On another Western Transvaal gold mine, Moh-9 ceramic impellers replaced rubber ones pumping slurry with an average particle size of 10-15 mm. The ceramic impellers lasted more than 1,272 hours, compared with 96 hours for rubber. Similarly comparing Ni-Hard and Moh-9 ceramic impellers in a mine application, the yield drop of the Ni-Hard unit was almost 41% at the end of its operating life, 28 days after installation. The yield of the ceramic impeller dropped by just some 2% over a 70-day period, compared with the total average drop of 17% for the Ni-Hard unit over the same period.

A variety of innovative mineral processing equipment is offered by Multotec, such as its range of large diameter cyclones. Traditionally, dense medium cyclones have been fabricated from cast iron and the largest size was 750 mm. Multotec introduced 800 and 1,000 mm dense medium cyclones, made from mild steel and lined with pre-engineered alumina tiles to give maximum abrasion resistance. They have been designed in both standard and high capacity models the latter can treat 30% more coal compared to the standard model.

Both models come as standard with an extended barrel section proven to increase cyclone efficiency. Currently a high capacity 1,000 mm unit and six 800 mm high capacity units are working in the U.S., and orders have also been won in Australia.

Multotec has also developed a new spiral profile which enhances performance and efficiency in fine coal washing. It incorporates an 'auto reject channel' located about the spiral centre column. Increased efficiencies are achieved through use of the circular transversal flow in conjunction with the auto reject channel. Advantages include: elimination of beaching of coarse particles; improved removal of high density particles; increased fluidity about centre column resulting in an increase of slimes removal; higher reject capacity; improved removal of misplaced particles through circular transversal flow; and no auxiliary splitters. Several of these spirals have been exported to Eastern Europe, North America, Australasia and Europe.

Its combination slurry sampler incorporates a primary and secondary sample in one unit, thereby eliminating a secondary reject stream and can be fitted to pipes from 100 mm to 600 mm NB in size. All wetted surfaces are rubber lined to ensure long life and a splashproof drive unit with sealed bearings gives durability.

Distributed exclusively internationally by Multotec, AEC's Frothman measures both air-froth and froth-pulp interfaces. Operators can measure and control froth thickness with the Frothman in any conventional flotation cell. Various parameters can be used to control the froth such as frother addition, reagent addition, aeration rate and pulp level. An 'expert' control package has also been developed which can be customised for the flotation plant. The device is used extensively in Chilean copper mines for froth control in roughers, scavengers and cleaners.

Osborn MMD is a minerals processing and materials handling company, part of the Boart Longyear group, specialising in crushing, screening, feeding, milling, scrubbing and conveying equipment and turnkey plant. It operates under three major divisions; Equipment Sales, Projects and Parts. Recent projects include the supply of feeding, screening and conveying equipment and plant for Namakwa Sands; the supply of the coal crushing and screening plant, the largest of its kind in South Africa, for Sasol's Syferfontein mine; and a slag crushing, milling and classifying plant for Ferroserv.

The last of six new Euclid R 220 trucks was recently commissioned at Palabora Mining Co's (PMC) copper open pit. These trucks, each capable of hauling in excess of 190 t, are all equipped to operate on PMC's trolley assist system. The units were all manufactured at Premier Equipment Co's manufacturing division, PEMCO. Premier is Euclid's distributor in South Africa and operates the only Euclid manufacturing plant, other than the Euclid parent facility in Guelph, Canada, licensed to build mine haulers. Premier was also involved in the design of the R 220, and the PMC units are the only ones operating anywhere around the world as yet.

The Euclid R 220 is a rigid-frame rear dumper powered by Cummins KTTA 50E-1800 diesel engines developing 1,342 kW at 1,900 rpm, driving through General Electric Model 788 wheel motors. The trucks are equipped with new 18-element resistor grids which have increased the dynamic retarding capability to about 3,800 kW. The grids control the excess electrical energy from the overhead trolley lines which is not utilised by the wheel motors until they reach rated operating speeds. Another major innovation is a constant-velocity hydrostatic blower which provides continuous cooling for the wheel motors.

According to Steve Campbell, Premier's mining equipment product manager: "The Euclid tapered box beam frame is recognised worldwide for its inherent integrity, which ensures a longer life for the unit due to its superior bending and torsional stress capabilities, while at the same time eliminating excess weight."

The PMC units use a specially designed 108 [m.sup.3] capacity bowl to cope with the material densities at Palabora. The bowl is fitted with a complete rock liner kit of abrasion-resistant Roq-Last steel. All sheet metal and form-work as well as the bowls were manufactured at PEMCO.

The range of Tornado vertical shaft impact crushers from Pilot Crushtec includes units with capacities ranging from 5-180 t/h. Tornados have been exported to East and West Europe, the Far East and Australasia. In 1991, the company developed its revolutionary Pilot modular rotor for all makes of vertical shaft impactors or autogenous crushers. It reports that market demand for this product has proved exceptional.

Rack Lift International designs and manufactures rack and pinion drive hoists for the conveyance of personnel and materials under the most strenuous mining conditions. Racklifts are self-erectable, modular and can be designed for most applications (400 to 4,000 kg), at any angle and unlimited vertical travel.

Rham has designed, developed and sold more than 500 machines to the underground coal industry, setting new standards in roofbolting technology by working with the user to improve safety and increase productivity at the lowest cost. Rham has focused its efforts into mobile self-propelled hydro-mechanical equipment and services. The equipment works in seam heights from 0.8 to 6 m and can be track mounted or on solid-bonded wheels with fail-safe brakes.

The Rham high seam EM500, for example, is a roofbolter that is operated remotely from the safety of the cab. When loaded, all drilling, resin injection and bolt installation functions are completed remotely. More than 30 of these units are in operation.

Rham's patented resin injection system enables a full-column resin-grouted roofbolt to be installed at a seam height of 6 m from the safety of the operator station.

Rham has exported low seam roofbolters to Europe and China, as well as face drills. Three high seam, twin boom units, the SAATB 5000, have gone to China, designed to work in entries up to 6.5 m wide and 5 m high. The low seam 30LS unit can work in seam heights from 800 mm. Ryan Mining's Lyn mine in South Wales, U.K., has three of these that are used for high density bolting in room and pillar mining.

Rhino Safety Products particularly specialises in Fenzy breathing apparatus and Comasec gloves. The latter, locally-made, are a range of materials-handing safety gloves, including the Dynatril range which, Rhino reports still represent the most advanced materials-handling glove locally available. Rhino's primary export markets are Africa and South America.

From its inception some 25 years ago, RUC Mining Contracting has grown in stature to where today it is recognised throughout the world for its specialist and innovative capabilities within the mining and related industries. Comprised of a number of inter-related companies specifically created to meet the requirements of mining, the RUC Group is backed by an experienced management team which can provide working solutions for a variety of tasks. This includes exploration, mine planning and establishment of on-going construction work on mines, through to final mine closure and rehabilitation. The group has been extensively involved in a number of shaft sinking contracts in Southern Africa, Australia, South America, Greece and the Pacific Rim countries.

The group includes the Geoseis, Spectrum Information Technology, Unidrilling, Rucmin, Rucbor, Rucsacs and Strata Boring companies.

Geoseis offers one of the most technologically advanced geophysical data acquisition and processing services in Africa. It relies on airborne and seismic data acquisition and is capable of providing both 2-D and 3-D, high resolution seismic surveys. Integrated document management and work flow applications for the scanning, indexing, storing and retrieval of paper-based or computer generated documents are undertaken by Spectrum Information Technology. The company's capabilities also include geoscan, seismic scanning and reconstruction for scanning and trace reconstructions that produce digital traces in SEG-Y format. Up to date document management systems ensure that Spectrum can meet the needs of a wide range of applications.

Unidrilling operates a large fleet of diamond drilling machines, both surface and underground. In addition, the company utilises a successful directional drilling technology to drill slim holes to depths of 5,000 m.

Large shaft sinking and construction projects are the speciality of Rucmin which has sunk shafts to depths in excess of 1,600 m. It has set a number of shaft sinking records over the past few years and boasts extensive experience in both Southern African and international markets. Contracts have been undertaken in U.K., Peru, Chile, Zambia and Australia.

Rucbor is one of the largest raiseboring companies in the world undertaking major raises and shaft boring and operating three Wirth HG 330s - the largest raiseborers in the world. These units have enabled the company to raise bore holes of up to 6.5 m in diameter and in excess of 1,000 m deep in hard rock mines. Rucbor has successfully bored shafts in Australasia and South Africa.

Rucsacs speeialises in underground support systems, civil and mining construction, as well as contract mining in coal, gold and base metals. The company's services span the full range of surface civil engineering requirements, tunnelling and underground civil construction including shaft pre-sinking, silos and storage bunkers, ore pass construction, and conveyor installations.

Strata Boring provides maintenance and service back-up for the raiseboring industry at large. It maintains an extensive parts stockholding as well as exchange units for raiseboring and boxhole boring machinery.

The broad spectrum of mining services provided by each of RUC's sub groups, coupled with the successful completion of a number of projects around the world, have established RUC as a leader in its field. The company is capable of undertaking both small- and large-scale projects, which includes small specialised services through to fully-integrated turnkey projects.

The Saflec scientific range of metal detectors is designed to address the problems of finding small quantities of precious metals which are being stolen from the work place. Typical applications are in both mines and precious metals refineries.

Saflec tackled the problem of the body effect in metal detectors (where the body effect signal is greater than that from a small piece of metal hidden on or in the body) some years ago. The problem was overcome by the use of high speed computers to separate the human body effect from the true metal. For products such as its Goldfinger metal detector, Saflec will further increase sensitivity and detection rate and upgrades will be passed on to existing users; the basic detector remains in the same format, only the software and some electronic sub-assemblies will be changed.

Saflec also offers anti-abrasive systems in which high-wear areas are studded to create a 'rock box' effect. The grid arrangement of the wear studs ensures that excavated material is trapped between the studs. This creates a wear-protection surface in contrast to conventional wear plates which are exposed to permanent abrasion.

Scaw Metals is one of the world's leading and largest foundry groups, making a wide range of ferrous castings, and is one of the world's leading manufacturers of grinding balls. Scaw is also a manufacturer of high-chrome carbide overlay plate. Operating machining and fabrication facilities, Scaw manufactures to customers designs and specifications.

The current range from Scorpio Scrapers includes primary, secondary and V-plough belt scrapers, impact saddles, belt washing systems, rotary brushes, air cannons, a skirt block system and an environmental vacuum system. All scrapers feature adjustments for horizontal and vertical alignment and self-tensioning options are available. Scorpio claims to be the first company to have introduced a sliding cradle system for the easy and safe withdrawal of scrapers for blade inspection.

The engineering services offered by Shaft Sinkers cover coal and metal mine construction, underground metal mine operation, metallurgical plant and the development of infrastructure/-transport. Shaft Sinkers is active in Africa and South America.

Last year Shaft Sinkers completed an eight-year shaft sinking and development contract at Vaal Reefs No.10 shaft.

The Smith Capital Equipment division of Smith Mining Equipment has evolved a rare approach to the development of capital equipment. It has organised its operation to develop specialised capital equipment efficiently, and cost effectively, on the basis of short runs, while maintaining the necessary parts and service back-up. The product line includes a wide variety of surface and underground drilling machines and underground utility vehicles.

Relatively new from Smith Underground Equipment is the AP 750 hydraulic drifter which the company reports "simply converts the power into blow energy more effectively. The impressive penetration rate is achieved without exceptional percussion power or pressure, 16 kW at 160 bar." Weighing 145 kg, it is designed for holes from 38 to 89 mm in diameter.

The unitary body has only one body joint - at the rotation module - to facilitate component assembly. The drill comprises just 44 different parts, 88 items in total. This is less than half the number for most other drills. The AP 750 can be fully serviced and repaired in the mine, right on the rig, while still mounted on its cradle. All parts pull out from the front. Downtime is thus significantly reduced, as well as repair costs.

SMX has come to the forefront of the South African explosives market in less than 10 years. It is a division of Sasol Chemical Industries (SCI), wholly-owned by Sasol, the world's only commercial oil-from-coal venture. Sasol has operations in coal mining (40 Mt/y), synthetic fuels, chemicals, oil refining and fuel marketing.

SMX manufactures and markets a full range of Anfo, emulsion and watergel blasting explosives. As part of its ongoing commitment to remain at the forefront of technology, SCI formed a joint venture with Ensign-Bickford of the U.S. in 1992. Ensign-Bickford (South Africa) now manufactures a full range of advanced explosives accessories, including Primadet shock tube detonators, Prima-cord detonating cords and Trojan cast primers.

Several new product systems with international growth potential have been developed by SMX in the last few years. The latest, PPM, is a unique ammonium nitrate technology that allows the production of a more sensitive low-density porous prilled ammonium nitrate. Trials at South African, Chilean and North American mines show PPM Anfo and heavy Anfo to offer significant cost benefits in underground and opencast applications.

One of the first mainly mining-orientated consulting firms in South Africa to export its services around the globe was Steffen, Robertson & Kirsten (SRK). From its inception in 1974, SRK has been involved in numerous projects outside South Africa, initially in neighbouring states such as Zimbabwe and Zambia, and later in other parts of Africa and many overseas countries.

To date SRK specialists from South Africa have assisted with mining ventures on five continents. In Africa, for example, the firm has been involved with ZCCM's Nchanga open pit continuously since 1974. In Chile SRK recently completed a mine planning review for Chuquicamata, the world's largest open pit, and has been invoked on most of the major mines, including El Teniente, Collahuasi, Mantos Blancos and CMP iron ore mines.

Currently SRK is involved in projects which include the Lena River gold feasibility study in Siberia, Tarkwa gold in Ghana and with Western Mining (Gold and Nickel Division) in Australia.

At present, cross-border and overseas project work contributes some 20% of the South African practice's total income, and the intention is to keep that figure below about 25%. In so doing, SRK will be looking to work closer still with its well established international offices in Vancouver, Denver, Reno, Columbia and Cardiff, as well as those recently established in Santiago and Perth.

Co-founder and chairman Oskar Steffen comments: "As a leading consulting firm in a strongly mining orientated country, SRK has always been delighted to consult to discerning clients around the world. One of the reasons for our success in the international arena is the firm's acknowledged technological skills in geotechnics, mine planning, water/waste engineering and environmental science and engineering. When you factor in other advantages such as competitive exchange rates, and close interaction with local mining houses, manufacturers and contractors you have a winning recipe. We anticipate that as mining activity expands in regions such as South America, Africa, Asia and Australia, SRK's services will be increasingly in demand."

The product line of Walter Becker includes transport systems, pumps, underground communications systems, underground supports and pneumatic and manual lifting gear.

The company designed and installed the world's first underground monorail system to incorporate a front-end loading system, with a bucket capacity of 0.75 [m.sup.3]. The system was put into operation at the President Steyn gold mine in 1992 and has proven successful. Walter Becker claims that its advantages are high transport and loading capabilities without pollution of the underground environment. It offers powerful climbing ability, footwalls remain unobstructed and face lengths can be extended with a reduction in the costs of development and boxholing. The system is ideal for application in areas with narrow drive cross-sections at great depths. It can negotiate turns as tight as 4.1 m.

The loader is hydraulically operated and has a breakout force of 600 kg. Ore is loaded into containers operated by the transportation unit. Container loading and the conveying process are continuous. The 6 t capacity containers are deposited for loading and then retrieved when full for discharge into the orepass serving that particular mining panel. One loading unit serves three stoping panels and is capable of handling some 50 t/h of ore.

Yeltech's Easy Ranger is a pulse laser distance measuring device. Brought out in 1988, it has since been improved considerably with new features added. The latest model, the ERII-50A, includes removable, rechargeable on-board battery; touch-pad keyboard; 1,000 point memory and user-friendly on-board program. It can be hand-held or tripod mounted and measures distances and angles to any surface. Aiming is by means of a red-dot sight for above-surface application or a laser pointer for underground applications. The RS232C data port is used for downloading stored measurements or for use with a data recorder.

The Easy Ranger was used at the recent slimes dam disaster at Virginia in South Africa. Urgently required was a calculation of the volume of mud which drained from the dam when the wall was breached. Aerial photography would be too costly and the results would be available only after four weeks. Conventional total station survey was impossible as it was too dangerous to walk into the cavity.

A couple of control points were established on the perimeter of the cavity which was about 300 m wide. The Easy Ranger was used on a tripod with a Psion and Totac program. Both angles and distance were measured and recorded at the press of a button and over 1,400 points were measured in about three hours. These were downloaded to a PC, contours drawn and volume calculated. The volume determined by aerial photography a few weeks later was within 5% of the Easy Ranger volume.

Mining products from South African manufacturers are showcased in Johannesburg every two years at Southern Africa's premier mining exhibition, Electra Mining, organised by Specialised Exhibitions (fax: +27 11 496 1161). The next Electra is September 30 to October 4, 1996.