HIGH-TECH UNDERGROUND MANLESS MINES; As the industry shifts to

The Boy Scouts’ motto, “Be prepared,” is equally applicable to today’s mining industry as more and more companies struggle to adapt to new trends. Four years ago, the industry began a shift toward so-called manless mining systems. Skyrocketing labor and regulatory costs, it was argued, were cramping the ability of Canadian mines to compete internationally. Automation, the next step up from mechanization, was touted as the industry’s salvation.

At a national conference on automation held in Sudbury a couple of years ago, one participant suggested the industry champion the cause by adopting the slogan: “Not a man underground by the year 2000.” While that idea may sound farfetched (after all, two-thirds of all underground workers do not operate machines but maintain them) mining companies have made significant moves in that direction. The Canadian Centre for Automation and Robotics in Mining, was established in Montreal in 1989 and the Mineral Technology Council of Canada (MITEC) has been organizing seminars so that manufacturers can rub shoulders with miners in the hope that more high-tech gadgetry is transferred underground. In short, the industry is preparing itself for a shift to automated mining — mining orebodies with machines, controlled not by men but by computers, either underground or on surface.

Part of the preparation involves searching for better ways of maintaining existing manual mining equipment. The strategy is to transfer that technology eventually to the automated mining machines in place in the 21st century and to ensure that workers are skilled in making the technology work. To use an analogy suggested by Dr. W.R. (Bob) Dengler, chairman of Dynatec International, the game plan is akin to orbiting the Earth before embarking on a mission to land on the moon.

Some practical ways of moving toward automated mining were presented to about 265 maintenance engineers/managers who gathered at the Canadian Institute of Mining and Metallurgy’s sixth maintenance meeting in Sudbury, Ont., in February. Dengler was the keynote speaker, and perhaps the biggest surprise of the meeting was the agreement that greeted his assertion that the industry is doing a “lousy job” of maintenance. “The sad thing,” one maintenance manager told us after the speech, “is that he’s right. Part of the problem is technical and part of it is people. We’ve been telling our workers for years what to do and now we’re asking them for ideas on ways to improve things. And it’s just not working.” While Canadian mining companies have one of the best-trained workforces in the world, few companies receive more than the bare minimum in terms of effort from their workers. “They’re only interested in putting in their seven hours, then going home,” said one conference participant. Others put the onus on management, which must learn to motivate workers.

While this attitude may not be representative of the industry as a whole, there are many things mining companies are doing to improve machine performance. What’s new about the approach is that many of the improvements involve so-called high-technology. Here are some of the ways companies are preparing for the automation of underground mines.

Audit

Inco’s Ontario division began cleaning up its act in 1988 by conducting a maintenance audit in certain areas of its operations. Most of the company’s 2,300 tradesmen are in their ’40s and have 20 years experience. As a result of a 4-month audit, the company, which spends more than $220 million annually on routine maintenance and repair in Ontario alone, developed standard maintenance methods and specific action plans to rectify any weaknesses. It also involved maintenance personnel in the new mine design process and in the purchasing of equipment. “The first audit resulted in improvements in all areas noted (in the audit),” said Donald Campbell, Inco’s manager of quality control. In fact, the 1988 audit was so successful that the company audited six more work areas in 1989 and plans to do six more this year.

Multi-disciplinary Approach

Dr. Larry Seeley, manager of metallurgical technology for Falconbridge, has some definite opinions on how to prepare for automation. When asked who will design the automated mines of the future, he responded: “We (Canadians) will if we focus our technological resources on the problem and if we get rid of the `not invented here’ syndrome.” Using medical technology as an example, Seeley explained that the key to technological success is what he calls the “multi-disciplinary approach.” To develop and implement this approach, project teams must be formed. They will determine the methods, the procedures and the manuals for automated mining.

Finding Supervisors

One important member of this team is the front-line supervisor. Where do mining companies find the best people for this job? Falco, with help from psychologist Peter Moon, has designed a program to help middle managers identify potential supervisors in their own workforce. But asking a miner who works on a bonus system to take a $20,000-a-year cut in pay to become a supervisor can be a tough proposition. Under Falco’s system, workers are asked if they are interested in becoming supervisors. Then, during a 2-day program, six candidates perform a detailed series of exercises designed to measure their skills in leadership, communication, analysis, decisiveness, judgement, and so on. Trained assessors then decide whether the candidate has met the standards and recommendations are given back to the candidate so he can plan his future. The program, modelled after one initiated at the Kidd Creek mine in 1975, assessed 36 candidates in 1989, twenty-three of whom where deemed potential supervisors. “We’re committed to hiring (and promoting) 25% of the best people available through this program,” said Falco’s staff training co-ordinator Jack Miller.

Despite a company’s best intentions, introducing new technology can be an abysmal failure. One mining industry supplier, Brospec, for example, began using “space-age” technology in the form of ceramic hardfacing in its shops in Howick, Que. in 1967. Disc brakes coated with ceramic materials increased the life of the brakes by 11 years, but the product was not accepted. “We lacked foresight and conviction,” said Thomas Brown of Borspec. Today, the company has taken another approach, organizing its workers into teams and marketing a number of wear-resistant ceramic coating techniques of particular interest to the mining industry. “To introduce technology successfully, companies need a commitment for research and development and employee participation,” Brown said.

Automated Hoisting

One area of many underground mines that has already become automated is the shaft. When Placer Dome was forced, because of a hoisting accident two years ago, to replace the skips, chairs and dump in its No. 8 shaft in Timmins, it also decided to enhance the automated ore-hoisting process. Under the old hoisting system, an operator at the 1,600-metre-level loading pocket would send the skips away once they were safely loaded. However, production would stop when the operator went on a break! Now the system is fully automated. Programmable “logic controllers” (PLCs), installed on the mine’s underground water pumps in 1985, worked so well that they were also used to automate the loading pocket operation. The automated system, installed in 1986, resulted in smoother, faster and more efficient operation, said Frank Chalmers, surface electrical shop supervisor for Placer Dome. During a 3-year, fault-free operating period, the number of 12.7-tonne skips hoisted during an 8-hour shift jumped to 152 from 127.

But in 1988 the shaft was put out of commission when a skip jammed and dislodged, snapping the hoisting cable in the process and falling to the shaft bottom. During the shaft rehabilitation process, more changes were made to the automated hoisting system at Dome. Proximity switches, manufactured by Canadian General Electric, have been mounted in the end-zones of the skip hoisting pathway to monitor when the skips have cleared a given zone and to detect a jammed skip. The company also has developed an elaborate computer graphics and performance-reporting system for the loading pocket. “We’re now running 160, 14.5-tonne skips per shift,” said Chalmers. Placer Dome is now changing its underground crushing system from manual to PLC-based graphics.

Plastic-coated Hoisting Cables

Advanced technology has entered the mine shaft in another way — through advanced materials. Four years ago, Wire Rope Industries of Point Claire, Que. installed a wire hoisting rope in a potash mine in Saskatchewan. The new rope, impregnated and jacketed with plastic, offers several advantages in the maintenance of ore-hoisting systems. Whereas lubricants are continually washing off of traditional wire ropes and have to be re-applied at a cost of about $50,000 to $98,000 per year per mine, the plastic-coated version (which costs about 20% more than the conventional type) requires virtually no maintenance. Only when damage occurs to the 30-to-60-mm-thick plastic jacket, are repairs necessary, said Jim Savory of Wire Rope. Also, the plastic jacket must be removed from the end of the rope in order to attach it safely to the shaft conveyance. The ropes are being used in two potash mines in Saskatchewan and at Brunswick Mining & Smelting’s No. 12 mine in Bathurst, N.B.

Automatic Rope Lube

Other mines have devised ways of lubricating traditional wire ropes automatically. Inco’s Levack mine, for example, developed a simple pneumatic system that has worked flawlessly for five years and has resulted in annual savings of about $16,000. Consisting of a barrel-mounted grease pump is controlled by a counter and two timers, the system sprays atomized grease on the wire rope after a certain hoisting cycle (30 skips). Two other Inco operations, the Creighton and Crean Hill mines, plan to install similar (but PLC-controlled) systems, said Dan Kay, Inco’s mechanical engineering technologist in the Levack area. Another improvement will include a fire-suppression system, manufactured by Wisconsin-based Ansul.

To lubricate hoisting cables, Inco is even experimenting with a grease developed by Esso Petroleum Canada for open pit equipment. “Various gears that have been lubricated by the grease for six months still show the original machining marks,” said Ken Hildebrant, senior technical specialist for Esso. The grease was designed for use in operating conditions typical of Canadian mines: temperatures from 40^o (deg) C to minus 40^o (deg) C; excessive dust and moisture; wear, rust and corrosion. The grease can be easily removed for maintenance inspection. Inco has been testing the grease as a wire rope dressing since June, 1989.

Automated Train Haulage

An even more automated ore-handling system exists at the Golden Giant mine in Hemlo, Ont. Ore from that mine’s ore pass system is fed through chutes into 20-tonne-capacity, bottom-dump ore cars on the 4335 level. The (unmanned) PLC-equipped locomotive is controlled remotely during the loading cycle by an operator in the surface control room, using video monitors. The locomotive is then placed on automatic control and hauls nine cars to a coarse ore bin that feeds into the underground crusher on the 4295 level and returns for another load. PLCs also monitor the ore feeder, crusher, discharge conveyor and levels in the fine ore bin. The 4235-level loading pocket below the crusher is fully automated as is the production hoist. Having achieved a hoisting record of 6,000 tonnes in a 24-hr period, the company is now looking seriously at increasing the speed at which the 16-tonne skips are hoisted along the 1,145-metre distance to surface, said Peter Case, mechanical technologist for Hemlo Gold. An increase in speed to 12.9 from 8.9 metres per second is being considered.

What’s new about the automated ore-handling system at Golden Giant is the way data are transmitted from the moving locomotive to the computer on surface. This is accomplished by a “leaky feeder” system rather than through a hard-wired “data highway.” Data from the PLCs on-board the locomotive are transmitted to the leaky feeder cable via data radios. The leaky feeder cable is basically a cable with holes in its insulation jacket so that radio signals, in the form of radio frequency energy, travelling in the cable can “leak” out and be received by 2-way radio equipment.

Mine-wide Data Exchange

The leaky feeder system has been used for several years for underground communication systems. Sudbury-based El-Equip, for example, has been marketing such systems for several years. “The leaky feeder has become the system of choice (over medium frequency inductive systems, which use existing pipes and cables as an inductive medium) for transferring voice and data by radio because it approaches the reliability of telephones,” said James Hackwood of El-Equip. There is a disadvantage, though, to a leaky cable — because radio signals leak out into a drift, signals become weaker with increasing distance along the cable. Special 2-way in-line VHF amplifiers are used to amplify the signals. These amplifiers, spaced from 350 to 500 metres apart, add to the cost of the system. “While the leaky feeder is the system of choice today, the system of choice for the future will involve multiple channel voice and data systems, capable of incorporating video and computer information, transmitted from semi-automated and automated equipment,” Hackwood said.

“Although 90% of all mining projects require a data exchange network, most of them can’t afford to operate the network continuously,” says Bill Valedis of Modicon Canada. “There is so much high-tech jargon that it has caused a lot of confusion. It is common to hear that such-and-such system is the best way to go, but no good reasons are given.” To state the obvious, Valedis suggests mining companies train employees in new technology and involve their technical people in the design stage. He has seen many companies experience frustration when they introduce new technology. “One way to solve a lot of problems is to go out and talk to a supplier. There are a lot of good suppliers in the industry; all you have to do is tell them what you want to accomplish.”

Ontario Rebates

There are definite advantages to monitoring electricity use by computers. The Golden Giant mine, for example, saves a considerable amount of money in electrical energy costs by simply delaying ore hoisting by three minutes during peak electricity demand times. Another mine does crusher maintenance in the afternoon instead of morning so that it can run the crusher during off-peak hours, says Mel Harju of Ontario Hydro. Ontario Hydro is developing a software package designed specifically for the mining industry to analyze its electricity use. The utility is also actively promoting the use of high-efficiency electric motors and lighting in mining. The utility will pay up to half the cost of such items. Rebates on motors, for example, can be as high as $2,400. One application for a rebate on a motor replacement for a screening operation is expected to save a particular mining company one million kilowatt hours per year, Harju said. Another mining company has applied for a rebate on a lighting system in an underground mine.

Managing Energy Use

Like the automated factory, electricity will power the automated mine of the future. A few underground mines currently manage their energy consumption using sophisticated, computer-based monitoring systems. This is another way mines are preparing for an automated mining cycle. Falconbridge, for example, which paid out $3.9 million to Ontario Hydro in 1989 alone, has installed such a system at its Onaping area mines on the north rim of the Sudbury Basin. The system consists of five IBM PC/AT computers, one at each mine, mill and service shop. These units are linked by the Bell utility lines and a locally installed co-axial cable network. Digital and analog Opto 22 input/output controllers acquire real-time data about energy variables (kw demand pulses, steam pressure or flow, natural gas flow, compressed air flow, etc.) and relay these data to the IBM computers. The computers are programmed to maintain the average electricity demand over each 15-minute period within a pre-selected peak limit. This is accomplished by a control strategy which shuts down various pieces of equipment (or delays their start-up) according to a list of priorities designed to meet the program goal.

Data on energy consumption are used by mine operators for a variety of purposes. The area superintendent, for example, uses the information to modify controls and change operations in order to reduce energy costs while maintaining maximum ore production. Maintenance planners, on the other hand, use the information to check running hours of each piece of equipment so as to schedule better preventive maintenance. Mine engineers can design development headings more efficiently knowing what the operating loads are on existing transformers and power cables.

“Clean” Electricity

The integrity of any piece of computer-based equipment depends greatly on the quality of the electricity supplied to the machine. So-called power transients (spikes or surges) can damage sensitive computer electronics, significantly reducing their operating life. So mines are preparing themselves for this problem as it may become an important maintenance item in the 1990s. Some electronic equipment has built-in surge suppression consisting of metal oxide varisters. But these deteriorate with use and may not possess the speed and capacity to protect against damage. Consequently, several competing electrical supply companies, including International Innovative Systems and Hubbell Canada, are marketing larger- capacity transient voltage surge suppressors (everything from adaptor-type units, for example, which plug into a wall socket, to large protectors at the source) to protect sensitive computer equipment.

Power Cables

Electrical power cables, capable of withstanding the harsh Canadian hardrock mining environment, will be key to the success of automated mining systems. The Canadian Standards Association (CSA) is preparing for an increase in the use of power cables underground by breaking away from its southern cousin, the Insulated Cable Engineers Association in the U.S. The CSA standards, which have been adopted by six provinces (Ontario will soon follow suit) take uniquely Canadian operation conditions, such as minus 40^o (deg) C temperatures, into account when approving cables for use in underground mines. Power cable manufacturers, too, are preparing for an increase in electric mining machines by manufacturing products that can withstand the abuse faced by cables underground. “The most common causes of cable failure are mechanical damage, excessive tension, poor splicer and terminating techniques and current overload and excessive heating of the cable,” said Gordon Baker of Phillips Cables.

And then, of course, there is Inco — traditionally a leader in the advance of underground technology. The company has just begun developing an underground orebody on the north rim of the Sudbury Basin. With enough ore to last 25 or 30 years, the company wants to prepare itself for technological advances yet to come. So they’ve installed 12 messenger cables in the main access drift leading to the orebody. What is each cable to be used for? “We don’t know yet,” area manager John Smith said. “but we want to be prepared.”