UNDERGROUND WHAT’S NEW HIGH-SPEED MUCKING

Diesel load-haul-dump machines (better known as LHDs or simply scoops) revolutionized underground base metals mining in the early 1960s. Their main advantage was the flexibility they offered. In the late 1980s and early 1990s, LHDs will be facing growing competition in underground applications where mucking is their sole requirement. Three new, high-speed, and in some cases, continuous mucking machines have entered the Canadian market, mainly in our big base metals mines. Competition between these machines and LHDs could become so stiff in the years ahead, that some mine engineers predict high-speed muckers will eventually replace scoops entirely. Jack Leikam, manager of LHD and truck marketing for Eimco Jarvis Clark (the world’s largest scoop- manufacturer), disagrees. “High- speed mucking machines will potentially have an effect on the market for scoops, but it is not practical to design a mine today without a scoop because they’re used for so many utility jobs, such as hauling backfill and supplies (jobs the continuous muckers cannot do).” Nevertheless, Eimco is not sitting still in the continuous mucking field. The company is developing a new machine at its research and development office in Gateshead, England. And a prototype is in use in Sardinia, an island off the west coast of Italy.

One of the advantages of attaining a continuous flow of muck from a muck pile is to “maintain the maximum productivity in downstream equipment, particularly conveyors,” says R. C. Relick, superintendent of Inco’s Copper Cliff North mine. “A continuous flow of material at a constant rate produces the most efficient loading action.”

The three manufacturers of continuous mucking machines that have competing models actively working in Canadian mines have the early lead in the battle for the big Canadian market. They are: Atlas Copco with its Haggloader cents , C ontinuous Mining Systems with its Osciloader cents and Voest-Alpine with its Alpine Loader cents . Only one of these manufacturers offers a Canadian-designed, -engineered and -manufactured machine — Continuous Mining Systems of Sudbury, Ont. Atlas Copco and Voest-Alpine are based in Sweden and Austria respectively and market their loaders through subsidiaries and distributors in this country — Atlas Copco through Atlas Copco Canada and Voest-Alpine through Wajax Industries. Haggloader

Atlas Copco’s Haggloader is one of the oldest continuous mucking designs still available commercially. It has been designed in two versions based on two carriers. The 7HR, 10HR and 12HR models are the most flexible. They are mounted on rubber-tired carriers and are electrically driven. The second version is the rail-type 8HR, which is available in either pneumatic- or electric-powered models.

The Haggloader’s unique digging arm-loading technique has been available for about 18 years. Rock is gathered by two steel gathering arms, which are operated by hydraulic cylinders. The rock is swept on to a conveyor and transported from the face to an underground haulage truck. Loading capacities are as high as 360 cu m per hour, which is equivalent to about 1,000 tons per hour, depending on the density of the rock being loaded. Hydrostatic 4-wheel drive enables loading on sharp inclines, as steep as 1:6, or about 10 degrees . A built-in sprinkler suppresses dust during mucking.

The height of the discharge end of the conveyor can be adjusted to load a variety of haulage equipment. The Haggloader is also equipped with a dozer blade which can be used for roadway maintenance.

The Onaping mine in Sudbury plans to commission a Haggloader this month. John Vary, mine engineer at Onaping, says Falconbridge Ltd.’s equipment department studied all the loaders available on the market and narrowed down the selection process to three. “We looked at all three and decided to go with the Haggloader because of its maneuverability,” Vary says. “We wanted something to muck in three different stopes connected by a ramp. So it has to move fast from stope to stope.

“When I visited the Kiena mine, Underground Superintendent Ernie Krisko sold me on the machine. They have it in a development heading loading 26-ton trucks and it takes about 2 1/2 minutes to fill each truck. They can muck out a whole blast in a couple of hours.”

Page-Williams Mine Superintendent Rory Mutch is happy with the Haggloader, too. It has been used at the Hemlo mine since October, 1987, in crosscut development work loading 26-ton trucks. “They can muck 1,200 tons a shift. It is so fast that they don’t have enough muck to keep it busy.” (It takes about two minutes to load the trucks.)

The Haggloader can work in headings ranging from 1.9 m to 6.5 m wide. Osciloader

Continuous Mining Systems (CMS) of Sudbury, Ont., has two models of its Osciloader cents on the market — the CL1000 and the smaller CL450. Both feature the patented oscillating loader lip which mobilizes or “fluidizes” broken rock or ore, allowing for a continuous flow from the muck pile to an on-line conveyor or underground haulage truck. The oscillating lip loosens up the muck, thereby reducing the force required to penetrate the muck pile. Both models are powered by electric motors. The 149-kw CL1000 can handle 1,000 tons of muck per hour and the CL450 can load 450 tons per hour. The CL450 also has a 15-kw secondary motor. The conveyor on both machines is wide enough (about 7 ft) to accommodate large chunks of muck. The machines are available mounted on either crawler tracks or rail wheels. Other features include ease of operation and maintenance. CMS has sold seven CL1000s to Inco Ltd. and has three CL450s on order from the same company. The first CL450 was to have been commissioned in the Copper Cliff North mine in Sudbury, May 1, 1988. Alpine Loader

Wajax Industries is marketing a third high-speed mucking machine which is in use in Canada. It is called the Alpine Loader (or AL 60 for short) and is manufactured at the Zeltweg works of Voest-Alpine Maschinenbau in Austria. The first AL 60 to be used in a Canadian mine (or any mine in the world for that matter) was commissioned in January, 1988, by Brunswick Mining & Smelting at that company’s No. 12 mine in Bathurst, N.B.

This machine uses the more traditional loader bucket to load muck intermittently on to an apron feeder which then feeds the rock onto a swivel-mounted belt conveyor and into an underground haulage truck. Brunswick is using the machine on the 1,000-m level to load 26-ton trucks.

The machine is crawler-mounted, self-propelled and fully hydraulically operated with power being supplied either by a diesel engine or an electric motor. High emphasis has been placed on a rugged and reliable design, according to the company. Voest- Alpine is also testing a rubber-tired model which will give the machine added flexibility, moving quickly between headings. That machine is being tested in Europe and could be available in North America later this year.

The 2-cu-m bucket on the AL 60 can handle the occasional large boulder of up to 1.5 cu m or 4 tonnes. The overall loading capacity is about 1,000 tons per hour.

The main advantage of the AL 60, according to Wajax, is its low fuel consumption of 18 to 20 l per hr. The higher speed of the loader means advance rates can be increased by as much as 18% over conventional lhd equipment, the company says. The machine was designed to operate efficiently in headings 15 to 45 sq m in area. Miner’s Lamp

N.L. Technologies of Scarborough, Ont., is marketing a miner’s lamp which is half the weight of conventional battery-powered mining lamps. It has a longer storage life and a life expectancy of 1,000 recharge cycles.

Called the Northern Light, cents it features miniature tungsten halogen bulbs, a contoured battery and modular, water-tight design. Bulb life is about 300 hr. The nickel-cadmium battery pack provides 10 hours of energy, is completely maintenance free and weighs just 1.36 kg.

All components are secured with stainless steel tamper-proof screws. Accessories include a charger frame, panel housing and a power supply module. Portable charger stations are also available.

Major mining companies in Canada already using the new lamp include Inco Ltd., Falconbridge Ltd. and Hemlo Gold. A One-man Grouting Machine

Craelius is marketing custom-built grouting equipment for underground and surface mines. Each unit consists of a grout mixer, agitator and pump, together with power unit for electrical, diesel or pneumatic prime movers.

The various pumps, screw feeders and feed equipment available can be combined as required to provide complete or partial automation. The aim is for a single operator to be able to operate the equipment. Fast Rock Hammer

Rammer Oy of Finland has developed a 200-kg hydraulic hammer which has an impact rate of 2,000 blows per minute.

The hydraulic system of the new hammer contains three pressure circuits instead of the two embodied in conventional hammers, the company says.

The third low-pressure circuit accelerates the piston, exerting a considerable force, since the area affected is three times larger than that in earlier hammer designs. The low-pressure circuit ensures that every blow is constant and, since it is completely closed, prevents back pressure from affecting the piston.

Oil consumption is about 20 to 100 l per min.

The breaking power, for relatively soft materials such as concrete, asphalt and frozen earth, is said to be double that of competing hydraulic hammers in the same performance and size range. The reason is superior penetratration.

The hammer can be mounted on mini-excavators, skid steer loaders and Bobcat type carriers in the 2.5-to-8-ton range, with oil pressures between 150 and 250 bar.

The hammers are marketed in Canada by Kent Air Products of Mississauga, Ont. — 30 —