What’s New in Mining: Raise Reamers

Raise reamers designed and manufactured by Machines Roger International of Val d’Or, Que. have entered the market.

The first machine was the V-30, capable of reaming an 8-inch pilot hole to 30 inches in diameter. The new V-50 (for 50-inch diameters) is expected later this year. The unusual thing about the Roger machines, compared with current raise borers, is that they use percussion hammers to do the reaming rather than friction cutters. This results in the cutting power being applied directly to the rock face by two pneumatic drills (three drills for the V-50) rather than indirectly through a string of rods transmitting a high pull-out pressure from a power plant placed in the drift above. The latter requires a substantial concrete foundation, while the Roger’s machine needs none.

Both down-the-hole machines on the V-30 are Mission drills fitted with 8-inch-diameter button bits. They are arranged concentrically to the pilot hole and proceed to drill out an annulus leaving a doughnut of rock between it and the pilot hole. The doughnut soon breaks off. With three machines in use, as in the V-50, two concentric channels are drilled out leaving two corresponding doughnuts of unbroken rock between them.

The machines have been extensively tested in Canada, Australia and also South America on raises up to a maximum of 300 ft. (90 metres) in length, but more generally in the range of 75 to 175 ft. (22 to 52 metres). Dips have usually been steep: 65deg to 90deg. Each hammer needs 600 cubic feet per minute (c.f.m.) of air, and mine air (at 90 lbs. per square inch, or p.s.i.) is boosted to 300 p.s.i. before transmittal down the drill string to the drills. A total of about 175 hp is needed.

Undoubtedly, the innate simplicity of the system and the ease with which it can be deployed will produce a positive response from the mining industry. The V-50 will soon be marketed, and the company is starting preliminary work on a tunnelling machine using the same principle.

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NARROW DRIFT BOOM

Frequently at the fore with new drill rigs, Toronto-based Atlas Copco Canada has introduced the Boomer H104 to the Canadian market. This is a single-boom, electric-hydraulic drilling rig designed and built particularly for production drilling in narrow drifts. The machine has been tested in Canada and New Zealand and has proved effective in narow-vein mines. The machine corners well and was found to work effectively while drilling in widths of 2.4 meters. It is highly manoeuvrable and visibility at the face during drilling is very good, according to Atlas Copco. The boom movement permits easy orientation for the drilling of toe holes. The H104 can also be used for the drilling of uppers.

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PEDESTAL BREAKER SYSTEM

NPK Manufacturing of Wickliffe, Ohio recently brought out new pedestal breaker systems for breaking oversize pieces in the primary crusher feed, both on surface or underground. A wide variety of models gives an operating reach ranging from 16 to 25 ft. (about five to 7.5 metres), and a number of hydraulic demolition hammers and power units are featured. Hydraulic hammers have a unique, gas-charged, direct-acting piston accumulator for maximum efficiency and are protected from impact and abrasion by heavy-duty mounting brackets. The boom is constructed for accurate alignment and is mounted on a compact, yet massive, base. Installation in a confined space is unlikely to prove difficult because of this feature.

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LARGEST WHEEL LOADERS

The world’s largest wheel loaders have been built by Caterpillar Inc.’s Mining Vehicle Center in Decatur, Ill.

The first such machine, a 994 wheel loader, is operating at an open pit mine near Tucson, Ariz., and the second is at a coal mine in Kentucky. Firm orders have been received in North America, and the company is hoping to break into the Russian market with an Arctic version.

The loader is ideally matched to trucks in the 136-tonne class. It has a bucket payload capacity of 31.6 tonnes. Buckets range in size from 14 to 20 cubic metres. The operating weight of the unit is 166.7 tonnes, length 16.8 metres and high lift clearance, 6.01 metres.

The power plant for the loader is the Cat 3516 engine, rated at 932 kw, giving a maximum travel speed of 20.9 km forward, 22.7 km reverse and a bucket breakout force of 95 tonnes. Three fuel tanks provide a capacity of 3,030 liters, allowing the machine to operate for 16 hours without refueling.

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HYDRAULIC BREAKER

A new simplified construction is one of the main drawing cards of Teledyne CM Products’ Model TB-925X hydraulic breaker. This breaker, like others in the Teledyne line, does not use accumulators, generally regarded as the costliest single maintenance item on breaker systems.

Teledyne has inserted a low-pressure nitrogen gas chamber near the piston head for piston recoil absorption.

The TB-925X can operate from carriers in the 35,000- to 88,000-lb. range, supplying up to 3,800 ft. lbs. of power. It can deliver from 400 to 600 blows per minute with a working pressure of 1,825 to 2,400 lbs. per square inch

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ROCKBREAKERS

Teledyne CM Products of Thornbury, Ont. has created two rockbreakers for portable and mobile crushing plants.

The systems, Models PB-12 and PB-18, have pedestal booms, remote controls, and electric-hydraulic power packs.

At a portable crushing unit, either breaker will improve operating safety and productivity. Teledyne engineers will make a no-obligation site survey to produce drawings for a field installation of the rockbreakers.

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CAT 793 TRUCK

This month, Caterpillar Inc. unveiled its new entrant in the big-truck category. The 793 is a 240-ton-capacity (220 tonnes) mine truck that has a top travel speed of 31 miles (50 km) per hour. It is powered by a high-torque-rise Cat 3516 diesel engine, and that muscle is delivered by a mechanical drive train that is 85% efficient. Caterpillar says the drive train components are up to 25% more efficient than electric drives.

This new leviathan will also feature forced-oil cooled, air-over-oil actuated disc brakes (front and rear), oil-pneumatic suspension and dual-slope design dump body with V-bottom centre. The overall length of the 793 is 42 ft., three inches (about 13 metres); the width 24 ft., one inch (about seven metres); and loading height 19 ft., seven inches (about six metres). The truck will be manufactured at Caterpillar’s Mining Vehicle Center, in Decatur, Ill. The Northern Miner Magazine plans to carry a more detailed report on the truck in an upcoming issue.

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P&H 4100 ELECTRIC MINING SHOVEL

The mathematics of open-pit mining usually comes down to a simple equation: bigger is better. In recognition of this simple, vital relationship, Harnischfeger has launched an electric mining shovel that can load in three passes a 240-ton hauler.

The New P&H 4100 shovel is an advanced, fast-cycling machine with a nominal 56-cu.-yd. (43-cu-metre) dipper, 85-ton payload and 28-second cycling time.

Beyond speed and brute strength, the P&H 4100 is outfitted with dual planetary propel and planetary swing; wide-track, heavy-duty P&H crawler undercarriage; deep mid-section boom and improved DC “Electrotorque” static drive system with programmable logic control (plc).

For its size, this machine is agile. It turns easily and can counter-rotate in tight quarters. And Harnischfeger says it has beefed up the front end. For example, the 60-ft. (11.3-metre) boom has a deep mid-section for improved strength and the super-efficient, widespread dipper achieves maximum dipper stability and a uniform cutting force right across the dipper lip. Harnischfeger can tailor the 4100 dipper to individual mine requirements.

The shovel delivers maximum crowd forces without excessive wear on the drive components through the exclusive P&H Powerband system. The maximum dumping height is 34 ft., three inches (10.44 metres) and the maximum bank-cutt
ing height is 55 ft., 7 inches (16.94 metres).

All mechanical and electrical components are fully accessible for ease of repair and maintenance. Other features include the following:

* Modular hoist, crowd, swing and propel transmissions for fast repair cycles.

* Built-in tooling for adjustments to mechanical equipment.

* Redundant brake solenoids on hoist and swing.

* Oversized disk brakes.

* Hydraulic jacks on saddle blocks for easy adjustment.

* Manganese dipper handle racks of the 57 size for maximum durability.

* Built-in plc maintenance dianostics to simplify and speed up trouble-shooting.

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P&H 2250 EXCAVATOR

Harnischfeger has introduced the largest and most powerful hydraulic mining excavator in the P&H line — the P&H 2250. This huge machine has a working weight of 373 tons (338 tonnes), a crowd force of 289,000 lbs. and a breakout force of 251,000 lbs. The nominal dipper capacity is 23 cubic yds. (17.6 cu. metres), but the range rises up to 33 cu. yds. (25.2 cu. metres) under certain applications.

Powered by a turbocharged and aftercooled 1,800-hp, 16-cylinder diesel, the 2250 boasts the latest technology in large hydraulic components, computer controls and single-engine proficiency. Harnischfeger notes that into this machine went a lot of engineering know-how and component extras.

For example, the four big, piston-type, variable-volume axial hydraulic main pumps proved twice the required capacity so they can operate at reduced speeds for longer life.

An exclusive, closed-loop swing system design gives the 2250 a swing cycle 30% faster than competitive excavators and also saves up to 15% engine energy per cycle, the company says. Another P&H exclusive is the 2250’s hydraulic viscosity control system, which automatically maintains hydraulic fluid at the proper operating temperature.

On-board microprocessors monitor virtually all the machine’s hydraulic power, diagnostic and control systems — from hydraulic fluids to engine speed to joystick movement.

The 2250 can dig 50-ft. (15.2-metre) bank heights and has increased dumping clearance and reach to load larger and higher haul trucks.

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OFF-BOARD CONTROL SYSTEM

Eimco-Jarvis-Clark’s Off-Board Control System is now standard equipment on all the company’s electric load-haul-dump machines. The concept was simple enough — Eimco removed the high voltage control panel, motor starter and motor disconnect from the load-haul-dump machine and mounted them on the wall or on a skid in a combination control box.

The result was a safer, simplified system that was easily serviced and resulted in less downtime than conventional systems, the company says. Standard and common industrial parts are used and there are fewer componenets for the disconnect, control-transformer and rectifier functions.

The system works this way: The motor is started by a control on the machine that activates the starter in the remote combination control box through a 24-volt direct-current feed back through the cable. With the motor running, the high-voltage alternating current system is fully isolated from the cable and motor and is double-insulated.

When the operator shuts down the motor before leaving the machine, the high voltage is disconnected back at the combination box. It is safer to walk near the cable, to climb on and off the machine and to perform service work on board.

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RAISE BORING CUTTER

Baker Hughes Mining Tools has produced a cutter product line for its raise-boring heads. The cutters allow for the interchange of three cutter models to handle changing rock conditions. No repositioning of the cutter saddles is required; only the cutters are moved.

The standard kerf spacing on Baker Hughes boring heads is two inches (or just over five centimetres), in concentric rings from pilot hole to the outside diameter of the head. The pattern bores efficiently in soft, medium-hard and hard formations. However, where very hard lavas and quartzites are encountered, field testing has shown one-inch spacing to be more efficient, producing large spalls about 1.5 inches wide, one to three inches long and a quarter of an inch thick.

The company has designed three cutters that can be positioned for 2-inch kerf spacing, or repositioned for 1-inch spacing using simple hand tools. When very hard rock is encountered, the cutters are moved to different saddles; there are only two bolts per cutter. This is strictly a field adjustment; no additional parts or special skills are required.

These new cutters (WTKC-4, 6 and 7) feature Baker Hughes standard metal-faced seals to provide maximum bearing life. Protected from dust and rock chips by the metal facing, the resilient seal retains and protects cutter lubricant. Tungsten carbide inserts in the cutter kerf provide maximum drilling speed and life.

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GETMAN SURFACE VEHICLES

After two years of development and testing, Getman Corp. of Bangor, Mich. has unveiled its Trammer 500 series service vehicle. The vehicles are intended for personnel and materials and are designed to eliminate the high maintenance costs of modified street vehicles. They are 4-wheel-drive units, 4.6 ft. (1.4 metres) high and powered by 57-hp or 79-hp Isuzu diesel engines. A major feature is a 2-speed, fully reversing powershift transmission that reduces maintenance, and the engine-transmission-axle combination is claimed to be suitable for grades up to 35%. Top speed is 15 miles (24 km) per hour. The vehicle weighs 6,000 lbs. (2,700 kg) and can carry a 4,400-lb. (1,980-kg) load.

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ELEVATING PLATFORMS

A second generation of Skyjack mobile elevating platforms is now being distributed by L.W. Matthews, based in Weston, Ont. There are three new models in the series: the SJ11 3220, SJ11 4620 and SJ11 4626. Constructed with an extensive work platform and extra-wide scissor arms of tubular steel, the whole is cross-braced to produce an assembly of great rigidity. The units are claimed to outlift and outmanoeuvre competing equipment two to one.

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OPEN PIT DRILL RIG

Ingersoll-Rand has recently introduced the DM-L, open pit drill rig. The unit offers pulldown forces of 60,000 lbs. (27,216 kg) and is designed specifically for production blasthole drilling to 180 ft. (54.9 metres) with a 30-ft. (9.1-metre) drill pipe change. For rotary bit applications, hole size range is 7 7/8 to 9 7/8 inches (200 to 251 mm).

With a high-pressure, air power pack, drilling hole sizes range from six to 8 7/8 inches (about 152 to 225 mm).

The DM-L is crawler-mounted, has hydraulic tophead drive and is fitted with a 2-man, thermally insulated and sound-attenuated cab.

The Caterpillar undercarriage incorporates a planetary gear system driven by two hydraulic motors rated at 174 hp (130 kw) each.

This “walking beam” system allows the rig to move over uneven ground without imposing excessive stresses on the main frame and drilling components the company says.

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CABLE-BOLTING SYSTEM

Thiessen Equipment of Langley, B.C. has introduced a bulk cable-handling system for cable-bolting and slinging. The new system features either a 2,000-ft.-capacity or a 4,000-ft.-capacity cable cassette mounted on a heavy-duty, tram-compatible skid.

Cable cassettes allow the operator to dispense safely any length of cable with complete accuracy. Convenient portability of the cable skid places bulk cable capacity precisely where it is needed. The new cable dispenser cassettes complement Thiessen’s existing pre-cut, pre-packed cable system.

The ruggedly built, 5×8-ft. (1.5×2.4-metre) steel-reinforced cable skid has standard features, which include cable end safety tail lock (in the cassette), hardened cable guides, cable length meter, air brake system and a cable lead locking guide for total cable control.

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HEAVY-DUTY CLEATS

A useful addition to the inclined conveyor belt system is the “Tatch-a-Cleat” line of heavy-duty convey
or belt cleats produced by Flexible Steel Lacing of Downers Grove, Ill. These provide a fast, economical method of customizing practically any type of conveyor used for raising loads up steep inclines or carrying loose, granular material more efficiently. The cleats are attached to the belt with screws or bolts, allowing easy, on-site installation or replacement.

Downtime is minimized and the cleats may be attached with simple hand tools. A number of differing shapes and strengths are available to handle materials ranging from iron castings to tree bark mulch.

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TEREX LECTRA HAUL TRUCK

Unit Rig, a division of Terex Corp. of Tulsa, Okla., is marketing a truck called the MT-3700, which is the ninth in its line of Lectra Haul products. The MT-3700 has a maximum gross vehicle weight of 685,000 lbs. and provides optimum shovel loader match over a payload range of 190 to 205 tons (172.3 to 185.9 tonnes).

A new suspension system, featuring nitrogen/oil struts with externally adjustable damping in the front as well as dual-rate, 2-stage damping in the rear, provides an unusually smooth ride. Other standard equipment includes an 1,800-hp diesel engine, General Electric 788 drive system and 37×57-inch tires.

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BLASTING SOFTWARE

For jobs that involve blasting, the comprehensive software package “BlastCalc” contains more than 70 conversion and calculation screens that tackle most blasting subjects, from amperes to velocity of detonation. BlastCalc is produced for the specialist blaster by Noka Software Systems of North Bay, Ont. and allows interactive calculating screens to test many different situations involving explosive products, loading methods, priming, rock types, patterns and the associated costs involved.

The product is suitable for pc/xt/at or compatible computers.

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NORDEX CONE PACKS A PUNCH

By Jim Patrick

Joe Thurow raised a few eyebrows when he left a Kirkland Lake, Ont. store with an armload of coffee filters. Some may have thought the Nordex Explosives vice-president had developed a caffeine problem after the company lost, through no fault of its own, two major clients last year. The filters, however, were actually experimental components for a new explosive device that may blast Nordex into the upper reaches of the sales chart.

At least, this is what Nordex President Cy Ross hopes. He says Nordex lost about one-third of its $6 million in sales last year when the Sherman mine in Temagami, Ont. and the Adams mine in Kirkland Lake shut down iron ore operations. But the new product, known as “Cone-Pak,” has picked up some of the slack. Ross said Inco has used more than 7,000 Cone-paks in November alone.

Cone-Pak is a shaped charge used for secondary blasting. A plastic cone 5.5 inches deep is packed with Magnafrac, a product of Imperial Chemical Industries (ici). The coffee filter, the prototype of which was bought at a Kirkland Lake store, provides a barrier between the charge and the plastic cap. The cone is slightly overfilled so that, when the cover is removed, the blaster can force the cone end with its viscous content against the rock surface. The shape of the cone directs the full force of the blast into the rock rather than dissipating the explosive force around the sides or behind the object. Blasters have found the rock may remain in place, but it will fall apart when rubble clearing begins.

Cone-Paks also come pre-assembled for quick use, they save time in placing the charge and hooking up the blast, and the controlled blast avoids damaging underground installations such as air lines, water pipes and support screens. A pole-holder is situated at the apex of the cone, which is colored white for ease of visibility underground.

Jim Patrick is a freelance writer based in Matachewan, Ont.

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