When hydraulic drills were introduced in the early 1970s, productivity shot up to an estimated 107 tonnes per man-hour. That compares with 13 tonnes per man-hour produced using the hand- held pneumatic jack-leg drill. Now, about 15 years later, computerized, hydraulic drill rigs are becoming accepted, even demanded, in more and more Canadian mines. At the three gold mines at Hemlo, Ont., for example, the operating companies have purchased big, new drill rigs that take more of the bull work and monotonous monitoring away from drill operators, leaving it up to micro-processors instead. These rigs are so big that the size of the mine openings is becoming a critical factor in getting the new rigs to the face.
Tamrock Canada, for example, delivered a new, computerized, long- hole drill rig (the Datasolo 1008) last March to Hemlo Gold’s Giant mine. Custom-built and assembled at Tamrock’s plant in Lively, Ont., just west of Sudbury, this diesel-electric rig runs on a 600-ft umbilical cord. It comes complete with a soundproof, reinforced operator’s cab and the capacity to drill 135-ft holes up to five inches in diameter in virtually any direction — all under micro-processor control. For new mines with the reserves to support many years of mining, these rigs are becoming more and more common.
The drill operator collars the holes, programs the depth and angle and changes the bits. But not everything is high-tech. In one of many practical design features, Tamrock has attached a steel vice to the back of the rig to hold the drill steel while removing the bits. Other practical features include a protective screen made of welded rebar over the windows of the operator’s cab and sheets of clear plastic over the outside operator’s panel. This rig also has the capability to retract drill rods automatically once a hole is completed to the designed depth. Sensors monitor the angle and depth of the drill hole and alarms are sounded at the first sign of trouble.
Tamrock has also shipped three other long-hole machines to three older operations in Sudbury — the McCreedy West, Frood and Stobie mines, operated by Inco Ltd. Unlike the big, new mines, the openings through which these rigs must be taken (to get to the active areas of these mines) are very small. It is understandable, then, that these long- hole rigs are less sophisticated than the Datasolo; they have no operator’s cab and are mounted on a more compact carrier.
Electric-hydraulic development jumbos are a big selling item for Tamrock along with all the other major drill manufacturers. The company sold a large number of units to mines in Quebec and Ontario in recent months. A particularly popular unit is the company’s narrow, one-boom jumbo (the 1.3-m wide Micromatic), according to Anthony Read, a sales engineer for Tamrock. This rig will be competing with other drill manufacturers for a chunk of the rejuvenated narrow-vein gold mining market in the months and years ahead. A number of such mines are scheduled to come into production over the next five years.
Sales engineer Read, who has been with Tamrock for four years, says his company’s products are earning a solid reputation in Canada for reliability. The Finland-based parent company, which markets machines worldwide, was so busy in 1987 that machines destined for European markets are being assembled in Tamrock’s Lively plant when floor space is available. This situation is not unique to Tamrock; other drill manufacturers are enjoying a productive year as well.
Boart Canada, a subsidiary of Boart International of South Africa, is preparing for even busier years ahead by expanding its plant on Fielding Road in Sudbury. The project is expected to cost about $1 million and will triple the floor space available for assembling drilling equipment. Since Boart burst into the Canadian market in the early 1980s with cut-rate prices on its drill jumbos, the company’s pricing has leveled off to the point where it now sees a stable future in this country, according to Peter Larsen, Boart’s technical marketing engineer.
The past 12 months have been the company’s busiest ever in terms of sales. Its biggest contract has been for four 2-boom jumbos and two one- boom jumbos which were shipped to Placer Dome’s gold mine at Detour Lake, in northeastern Ontario, where underground mining is now underway. Four of the booms used on these rigs are new BDS-50s manufactured by Boart at its Burlington, Ont., plant. This is a departure from the company’s earlier practice of using booms manufactured by Strommnes in Sweden. That company was purchased by Tamrock in 1986. Boart’s highly successful HD-150 hydraulic rotary percussion drill is used on all the rigs sold to the Detour Lake mine.
Boart is also breaking into the hydraulic long-hole production drilling market. Last year, the company designed a long-hole rig around the same HD-150 drill. Mounted on a 6-wheel carrier, manufactured by Standard Manufacturing, a U.S. manufacturer, it features skid steering for ease of maneuvrability and standard 4-,5- and 6-ft chains. A prototype rig has been operating at the Renabie mine, near Missinabie, Ont., since early last year.
All of the major drill manufacturers have concentrated their design efforts on mechanizing the production and development drilling part of the mining cycle. This effort has been so concentrated that the productivity gains provided by these highly computerized drill rigs are lost when the rigs are forced to sit idle while miners use much less mechanized machines to, for example, bolt and screen the back in a development heading.
It is this part of the mining cycle — bolting and screening — where we expect to see the most rapid developments in underground production drilling this year. Drill manufacturers as well as several mining companies are actively seeking ways to increase the productivity of this part of the mining cycle. The objective is to develop machines which will allow one miner to do the work of two in the same period of time or, better yet, in less time.
The installation of cable bolts has already been mechanized by Tamrock. Since the introduction to Canada of its first mechanized cable-bolting machine in Falconbridge’s Fraser mine in 1986, Tamrock has sold two more of these highly mechanized rigs in Canada: one to Inco’s Stobie mine in Sudbury and one to Hemlo Gold’s Giant mine in Hemlo. These rigs, called Cabolt rigs, which are operated by one man and come complete with a cement mixer and pump, can drill 50-ft holes anywhere from two to 2 1/8th inches in diameter, fill the hole with cement grout, insert one or two steel cable bolts and shear off the cables. Miners at the Stobie mine are using the rig to protect a number of big stopes in an old area of the mine.
As for inserting roof bolts which are only 6 to 8 ft long, two camps seem to be forming (in the Sudbury Basin at least) over this increasingly political issue. The inherent danger of bolting and screening has raised questions about how companies should deal with the responsibility for the safety of miners performing the work. In the past, mining companies provided miners with the necessary training to bolt and screen the back of mine openings in a safe, efficient manner. Then it was up to the miner to follow these procedures. Now, mining companies are seeking technological solutions to increase the productivity of the operation.
This issue is hottest in the Sudbury Basin where there are 14 underground mines operated by Inco Ltd. and Falconbridge Ltd. Both companies use rock bolts and steel mesh screen in all underground openings. Two solutions are being pursued.
At the Onaping mine, on the north rim of the Basin, Falconbridge Ltd. is using a protected man-basket/screen boom arrangement to bolt and screen the back of cut-and-fill stopes there (see separate story). The distance from the fill floor to the back is about 14 ft, but in an effort to get more productivity from these stopes, Falconbridge would like to take a bigger lift, making the distance to the back perhaps as high as 23 to 24 ft.
Inco, on the othe
r hand, is taking a different approach. Together with Spar Aerospace, the comapany is developing a remotely-controlled machine which can be operated by a miner standing 30 to 40 ft away from the actual drilling. Until the prototype is developed into a workable machine, many miners in Inco’s mines will continue to bolt and screen in the conventional way from sissor-lift trucks. At the Creighton mine, a new machine with a man-basket, hydraulic boom arrangement has been purchased. New Platform
In another stope at the Onaping mine (a captive cut-and-fill stope), miners are using a new, custom-built drilling and bolting platform designed by Phil Bellefeuille, an equipment technologist at Falconbridge. The unit was built by Miller Technology of North Bay, Ont. Designed to be an economic bolting and screening platform for reaching high backs, it is compact, relatively light-weight and inexpensive. The platform consists of a scissor-lift platform, which can reach as high as 22 ft, mounted on a crawler- type air track carrier. The rig is used for bolting with a conventional pneumatic stoper drill and screening in a captive cut-and-fill stope in the No. 3 zone at the Onaping mine. An adjustable steel arm pulls screen off a roll mounted under the platform and supports the screen while a miner drills holes and inserts rock bolts. Two other Falconbridge mines — Strathcona and Fraser — are looking closely at the rig as a replacement for steel staging which is moved from place to place with a scoop. A ONE-MAN ROOF BOLTER Teledyne Canada Mining Products of Thornbury, Ont., is marketing a big, one-of-a-kind bolting and screening machine which allows one man to perform the work of two. The machine is being used at Falconbridge Ltd.’s Onaping mine, on the north rim of the Sudbury Basin.
The machine has two booms — one with a man-basket and one to hold a 125-lb roll of steel screen in position while the operator drills 6- and 8-ft holes and installs bolts through the openings in the screen. The two booms are mounted on a unique tripod-type mine carrier (with two wheels in the back and one in the front) for added maneuverability in tight stopes. The steel turret which holds the hydraulic drill is mounted on the front of the man-basket and all controls (even for tramming) are in the man-basket. Two adjustable steel canopies serve to protect the miner from falling chunks of loose rock.
The machine, designed originally in France for large openings in soft- rock mines, was introduced to the Onaping mine two years ago. Several modifications, including extensive changes to the electrical circuitry, were made during that time in order to adapt the machine to some of the hardest-rock mining conditions in the world. The machine has been in full service since December, 1987, in three cut-and-fill stopes on the 4,200-, 4,300- and 4,400-ft levels. The machine is moved from stope to stope via a ramp which varies from 12.5% to 15%. Powered by either a 37-kw electric motor or a 4-cylinder Deutz diesel engine rated at 35 kw, the machine takes about 45 minutes to move from one stope to another. “If there is one complaint we have,” says Onaping’s Maintenance Superintendent Tom Mikola, “it is that the speed of the machine is too slow on the ramp. A 6-cylinder or a turbo-charged engine would do a better job.”
Equipment Instructor John Lagace, who trained the three miners who operate the machine, says: “My experience over the past two years has been that Teledyne has been behind its product 100%. They have never refused to come out and help us solve any problems we see. I think we have solved those problems now.”
Early this year, Falconbridge decided to replace the French-built RAH-24 hydraulic drill, originally mounted on the bolting machine, with an Atlas Copco 1032 drill purely for logistical reasons. The Swedish-manufactured 1032 drill is used throughout the mine on a number of development jumbos, so maintenance personnel are familiar with the machine and the company keeps a complete stock of replacement parts on hand.
Using the new Teledyne machine, a miner can drill up to 60 holes and install bolts in these holes in one shift, Lagace says. Using conventional pneumatic drills on a scissor-lift truck, miners at Onaping can normally install only 20 bolts per shift.
Falconbridge’s plan is to eventually be able to take a larger cut in its cut- and-fill stopes. With a maximum reach of 30 ft, the Teledyne machine appears able to do the job, according to mine engineer John Vary. The machine also allows one man to do the work of two in about the same amount of time — an important factor in Falconbridge’s efforts to increase productivity through mechanization. The cost of the machine is ultimately tied to the value of the Canadian dollar vis a vis the French franc.
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