New Mining Technology

Mining technology: scratching the surface:()Mining is going through a rapid and profound transformation. It is becoming a global industry, increasingly dominated by a radically shrinking number of global mining companies. ()/,/

Paradoxically, mining technology is not developing at anything like the same speed, even though some significant changes have taken place. Because mining is a global industry, its technologies are rapidly transferred between countries and there is not the same urgent competitive incentive to develop proprietary technologies that one finds in many other industries.

proprietary//;incentive //

Currently, mining companies are putting far more emphasis on finding new, higher-grade ore deposits worldwide than finding better ways to mine them. Demand for metals and minerals is up, and rising; so are prices.

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To some extent, the mining companies have actually withdrawn from the task of technological innovation as they focus on the urgent immediate goal of increasing production to keep up with demand.

keep up with

Further down the road, however, developing technology will not play as important a role in all sectors of mining as it has in the past. Mining may not be the oldest profession, but is possibly the oldest industry the earliest known mine dates back 43,000 years. Technological progress has always been the key to keeping mineral depletion and mineral prices in balance.,43000

Since the early 1900s, the National Materials Advisory Board in the U.S. points out, a relentless search has been under way for new and innovative mining technologies that can improve health, safety, and productivity, as well as mitigate the adverse environmental and ecological impacts of mining.

20, under way;

Mining technology innovations included the invention of the safety lamp, and safe use of dynamite for fragmentation, the safe use of electricity, the development of continuous mining machines for cutting coal, the invention of rock bolts for ground support, open-pit mining technology for mining massive, low-grade deposits, and the introduction of longwall coal mining.

The mining industry is currently setting impressive records in underground and surface mine production, productivity, and health and safety in all sectors (metal, industrial minerals, and coal). ,

In spite of this, the industry needs more effective and efficient mining technologies. For example, the inability to ascertain the conditions ahead in the mining face can slow progress and create health and safety hazards.ascertain/

As mining progresses to greater depths, the increase in rock stress requires innovative designs for ensuring the short and long term stability of the mine structure.

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Truly continuous mining requires innovative fragmentation and material-handling systems, said a 2002 report by the National Materials Advisory Board." In addition, sensing, analyzing, and communicating data and information will become increasingly important.2002

Mining environments also present unique challenges to the design and operation of equipment. Innovative maintenance strategies, supported by modern monitoring technologies, will be necessary for increasing the operational life of equipment and the mining system as a whole.

Mine technology development comes from a wide variety of sources. Some of the most radical and promising innovations are adaptations of technologies originally devised for other industries./.adapt for /;Advanced mine technology: some examples

Mining technology advancement today is progressing in several distinct areas, says Greg Baiden, Laurentian Universitys Canadian research chair in robotics and mine automation. The main areas of advancement are computer systems for engineering and geology, voice and data communications and surface plant control. (Laurentian)Greg Baiden.,.

Examples of the new technologies include mine design software, rock analysis software, and geology mapping software. Further advances in voice and data communications have seen the beginnings of tele-operation of mining equipment from LHDs (load-haul-dumps) and drills to robot arms..LHDS.

Surface plants have gradually seen the introduction of relatively advanced process control technology. For example, fuzzy logic controllers have been applied to mill operation./The following examples are just a tiny selection of the multitude of innovations the industry is making use of. /

Smart miningDeclan Vogt, in charge of mining research for South Africas Council for Scientific and Industrial Research (CSIR), is impressed with the potential of smart mining and its emphasis on measurement and precision to increase productivity.Declan vogt

There is scope for mining to catch up with other industrial processes, he says. Many of these are well measured and hence can be well controlled, while underground mining is not well measured in real time. So there is scope for considerable process improvement.

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As cheap wireless sensors become more widely available, it will become possible to measure the mining process as completely as, for example, a petrochemical process. We can expect to see similar productivity improvements as those already seen in other industries when the loop is closed and control is applied.,,/.//,

ProcessingAn example of what mining companies are doing in-house to improve their bottom lines and mining technology as a whole is Phelps Dodges copper concentrate leaching plant in Arizona, commissioned in 2003. ,Phelps Dodge2003 leaching/; concentrate//; commission//;

It was the first commercial facility to use pressure leaching to treat chalcopyrite concentrates. Chalcopyrite ores account for about 70% of the worlds known copper reserves. Concentrated pressure leaching provides an economical alternative to conventional smelting and refining methods for these concentrates. 70%.

The National Materials Advisory Board points out that the most important transformation of the mineral industry in the next 20 years could be the complete replacement of smelting by the hydrometallurgical processing of base metals.

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For this to happen, the trend that began with dump and heap leaching, coupled with solvent extraction-electrowinning and that was followed by bioleaching and pressure oxidation, would have to be accelerated, said the boards 2002 report. ,/-2002

Future research and development should be focused on innovative reactor designs and materials, sensors, modeling and simulation, high-pressure and biological basics, leaching and metal-separation reagents./

Virtual reality Mining companies in Greater Sudbury and Red Lake, Ont., have used giant screens to obtain three-dimensional images of the earth by combining drill-hole data, topographical maps, magnetic surveys and airborne photos.

Greater Sudbury and Red lake / (Airborne)

As a result, they are able to extract pertinent information much faster than in the past. For instance, they can devise alternative tunnel routes to avoid rock bursts by instituting mathematical processes. pertinent/;

The effect is the orebody coming off the screen, according to Andrew Dasys, managing director of Laurentian Universitys NAVNet, a research group affiliated with MIRARCO. Goldcorps Red Lake operation used this technology to make a $13-million decision to sink a shaft.Laurentian MIRARCO Navnet Andrew Dasys Goldcop 1300

Mine Planning As mining becomes more capital intensive and face advance becomes more rapid, there will be a greater need for information about the geometry and grade of the orebody prior to mining, according to Vogt. Geophysical techniques like ground-penetrating radar already have a lot to offer, but they will be improved and added to. Vogt

Geology will be integrated with data from other sources, like production drilling penetration rates, for example, to produce hugely improved short-range predictions of the orebody, and hence better mining. ,,

Geology will also move from prediction of the orebody alone to prediction of the surrounding rock enabling more effective layout and support design. Vogt says that borehole radar was developed by the CSIR specifically as a contribution to this area.Vogt /CSIR()

Underwater mining Greg Baiden at Laurentian University would like to open up an entirely new frontier in mining, one which would be heavily technology driven.Laurentian Greg Baiden /

For every person on Earth to achieve a First World lifestyle, he says, the demand placed on Earth resources would exceed our current resource output many times.

As India and China aspire actively to First World status, he says, keeping up with demand over the coming decades is going to be a huge task ./

What are we to do to meet this demand? Baiden asks. We as miners are currently limited to mining on 29% of the planets surface area. Can we double our mining output from land surfaces alone? Maybe. But if not, where are we to go? To outer space? I think the challenges there are well beyond our technology to date. Baiden 29%,?,,.

Far more tempting, he says, are the oceans, which encompass 71% of the planets surface. Currently, the oceans and lakes are untouched with the exception of oil and gas, and some diamond mining. 71%

Mining has not yet to explore underwater on a significant scale, basically because the technology does not yet exist, but Baiden has started to work on it. Mining robotics technology will allow the mining of large-scale mining deposits on the bottom of oceans and lakes. Baiden

The environment is hostile, to say the least, Baiden says. High pressure, extreme temperature, and a fluid mass that is highly impractical to support human life for the long term. (),,Baiden ,

Yet the geothermal potential of the earth under the oceans is tremendous. We are just beginning to open this new frontier in mining. Robotics and tele-mining will play a huge role in the opening of this frontier.

Automation and controlBetter automation and control systems for mining equipment could lead to large gains in productivity. The National Materials Advisory Board points out that some equipment manufacturers are already incorporating human-assisted control systems in newer equipment, and improvements in man-machine interfaces are being made.

Further down the road, however, research should focus on more autonomous vehicles that have both sensor capability and sufficient processing power to accomplish fairly complex tasks without human intervention. Tasks include haulage and mining in areas that are too dangerous for human miners. /

Semi-autonomous control methods should also be explored, such as fly-by-wire systems in which the operators actions do not directly control the vehicle but give directions to a computer, which then decides how to accomplish the action. autonomous//;

A good example of this technology is currently being used in large construction cranes; the motion of the crane to move a load from one location to another is controlled by the operator through a computer, which controls the rate of movement of the crane in such a way as to minimize the swing of the load. This technology has considerably improved safety, accelerated cycle time, and enhanced energy conservation in the motion of the crane.

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The Rand Corp. points out that remote and autonomous control technologies are still in the formative stages, and that there is a lack of consensus in the mining industry about how desirable they are. consensus; desirable/;Research and Development Corporation/;

These technologies are currently available for only a few specific tasks, such as remote guidance of LHD vehicles and continuous miners, operator-assisted drill positioning, excavator scooping, and vehicle tramming. ,(LHD)

Despite this climate of uncertainty, some of the requisite technologies are nearing commercial availability for several pieces of machinery. commercial availability;availability /;

Power sources for underground miningMining Technologies International (MTI), in collaboration with the Canadian federal governments CANMET-MMSL, is currently assembling the worlds first hybrid diesel-electric LHD prototype. CANMETMMSL --prototype/; hybrid; diesel;

The assembly will be completed in mid-2006 and the prototype will be tested and optimized at the CANMET-MMSL Experimental Mine in Val-dOr, Que. The hybrid 1.5 yd LHD will then be tested in four operating mines.2006CANMET-MMSLval-dor,Que ,1.5--

The main advantage of the diesel-electric technology is that it allows a significant reduction of the required ventilation due to a major improvement of air quality. ,

Further down the road, however, there is a need for research to focus on even cleaner and more flexible alternative power sources for heavy equipment, such as new-generation battery technology, compressed air, or novel fuel cell technology. novel;

The world as it will beThe mining industrys newfound prosperity and growth may paradoxically have masked the urgent need for new and better technology. newfound/; prosperity; mask//;

The industry seems to be too busy expanding production and taking advantage of its current prosperity, which follows many lean years, to focus on truly fundamental, long-term technological advances. take advantage of //;tooto ; lean years;

The increasingly global nature of the industry has also played a role in slowing the urgent need to develop new technology./ slowing/; urgent/; nature/;

Mining giants have swallowed other giants at an almost reckless pace, and one of the effects has been to enable the giants to go once again to where the orebodies are biggest, richest, closest to the surface and most easily mined by more traditional technology.

This allows the industry leaders to give priority to incremental change, bigger and faster machines, rather than to fundamental change. give priority to; incremental/; incremental change;

This is not to argue there is no fundamental technological change going on, or that incremental changes are not themselves crucial Most of the changes detailed above, in fact, are incremental. Some are fundamental, but merely adapted from other areas, such as applications of the GPS system from space technology to mining. GPS() going on=approaching/;

It would probably be unrealistic to expect the industry to fundamentally shift its priorities to technology programs. But it is not unrealistic to expect the industry to begin now, at the beginning of the 21st century, to think of its longer-term future. /21//

For its own sake, the industry leaders need to start devoting at least a small part of their newfound wealth to developing a mining technology for the world as it will be, rather than the world as it is now./,,

Lesson Two

Mechanization of underground mining: a quick look backward and forward

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AbstractMine mechanization, especially the mechanization of underground hard rock mines provides a large potential for reduced costs and improved profitability. This paper examines a number of successful developments mechanizing underground mine excavation, including raises, shafts, tunnels, and stopes.

It then examines mechanization developments, which are under way, and others which are not yet being developed. A look back at mine mechanization projects that have failed is included as a perspective when considering projects for the future.

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Factors influencing the development of mine mechanization are reviewed, as well as some of the factors that will be required for successful mechanization in the future.

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It appears that the development of mechanization for fundamentally new mining systems will require complex joint ventures involving mining companies, equipment suppliers, governments, and academic partners working together on a long-term commitment.

These technical joint ventures will require long-term commitments of capital to produce the technology that will be required for mechanizing the underground mines of the future./

1. We progress, but still we must blast Underground mining, like surface mining, has been a chronicle of mechanization since the earliest days of civilization. ,, chronicle//;

It probably started even before the Bronze Age, with the use of digging tools to pry minerals and metals from the earth. Things were still pretty primitive in the Middle Ages, as we can see from the records of Agricola, but the big steps were made during the industrial revolution as important improvements were made in pumping, hoisting and drilling.

Advances in drilling and the use of dynamite, and later other explosives, have produced a continuum of incremental improvements to the task of hard rock excavation. That technology is what miners must use today in planning a new underground mine. It's the state of the art.

Although the drill and blast (D & B) process is efficient, it is a cyclical process, which requires each step to be performed in sequence. One of those steps is very violent with large acoustic shocks, ground wave shocks, and flying sharp rocks capable of serious damage to the adjacent tunnel, the support system, and any equipment within close range. ,/

Another step is the required ventilation of noxious gasses, which are the product of the explosion, and there introduction of sufficient oxygen for the miners and machines.

In most cases, both the blasting and ventilation steps require all the miners and other personnel to be a safe distance away from the working face prior to the blast and throughout the ventilation phase.

In many mines, all personnel are removed from the entire underground mine prior to blasting.The D & B cycle can be planned and executed efficiently, but the stop and go intermittent nature of the work has a huge impact on the operations of the whole underground mine.

It is often true that the miners or tunnelers could produce much more footage of development drift, or produce more ore.

2. Mechanized continuous excavation For many years, machines have been used to continuously excavate soft minerals in underground mines. In some cases, this includes the soft, or weak rocks that surround the valuable mineral being extracted. .

Coal is probably the most common example. Much of the mine development tunnelling in underground coal mines is done in coal. If that is not practical, for example where tunnels must be driven in the over or underlying rock, the same type of machine can sometimes be used, especially where the rock is shale or soft sandstone.

Soft rock is commonly cut by drag bits, or picks, which penetrate the rock fabric with a highly loaded sharp point and rip through the rock in a shearing mode. Coal, salt, potash, and trona are among the minerals that can be effectively cut with picks.

Roadheader machines and coal mining production machines produce very large tonnages per hour using drag pick cutting. When the rock gets harder, pick wear and breakage increases, and very quickly down time for pick changing makes the use of continuous mechanical excavation much more expensive than drill and blast mining.,,

3. The long sought solution The hard rock miner views with envy the high advance rates and large tonnages produced by mechanical excavators in weak rocks and minerals. One can just imagine a hard rock mine where continuous miners chew tunnels and development drifts at high rates of advance continuously and without the constraints of D & B cyclic mining.,.

If a hard rock version of roadheader were to exist, much of the mine development would now be bored rather than blasted. Mine development in hard rock underground mines will undergo a major revolution when machines are available to tunnel continuously and productively. /

We are moving in that direction, but progress has been slow, too slow to fulfill the needs of the mining industry. Rolling cutters are used instead of pick cutters, and they use brute force to crush the rock. This has required brutish machines to provide the necessary cutter loading.,

4. Objectives of mechanization /; Let us review the objectives of mechanization. Among the most important objectives are the following seven items:: reduced costs; faster development; faster mining; safer mining;

mining with a smaller crew underground;;smaller capital expenditure;/;development of a more productive crew..

The most important of these objectives is mining with reduced costs. This objective will be accomplished if the other six objectives are achieved. Faster development will be among the most important objectives.

The cost of developing an underground mine is often directly related to the time it takes, from spending the first development money, to the time that ore is being produced from underground. /,

The interest on sunk mine development cost will always be an important cost item in underground mine development. Faster mining will result in lower costs for the same reason. Faster mining implies concentrating production in fewer locations and achieving higher production rates per shift at each of those locations. /,

Safer mining is a very cost effective objective. Mechanization can be applied to solve specific safety problems. One example of this is the large number of fatalities and serious accidents that occur in conventional raise driving in deep underground mines.

Development of a mechanized method to drill those raises and avoid the need for having miners working in that environment has made a big impact on mine safety.

Mining with a smaller crew underground has many direct advantages, but this objective also assumes higher mining and development rates of advance. If we can concentrate the mine output to one third of the locations by having much higher speed mine production, a smaller underground crew will be required.

A small underground crew can be a handpicked crew, with the highest quality personnel. They will also require a smaller investment in surface infrastructure and support. The use of less capital in the mine development is a major factor in the total cost of the ore produced, and one of the most important factors in the profitability of an underground mine.

Less capital will be used if high-speed development methods can be utilized from the very beginning of the mine development. This should include high-speed shaft sinking and decline driving as well as tunnelling and raise driving.

One must keep in mind that mechanized high-speed excavation may be capital intensive at the beginning, since the equipment necessary may require substantial investments, but the total investment over a period of time should be lower.

Developing a more productive crew will be an important objective of mechanization. The underground miners of the future must be carefully selected and trained to be able to operate the equipment and maintain it properly to achieve high-speed mining and development.,

A smaller, more productive crew will provide the possibility for higher wages and incentive schemes, which will permit underground mining to compete with many surface-based careers. incentive wages /

A more productive crew will be a safer crew. They can be motivated to have personal objectives that parallel those of the mining company.

Mechanization of underground mining, particularly mechanization of the excavation process, is an objective that can result in significant cost reductions and higher levels of profitability for underground mines.

5. What is now mechanized? There have been some notable successes in the development of mechanical underground excavation in hard-rock mines. Shafts are being constructed using shaft-drilling machines with shafts from 2 m to 6 m in diameter and to depths of 200 m to 300 m.2~6200~300

Shaft drilling machines use fluid to flush the cuttings from the shaft face to the surface with reverse circulation dual wall drill pipe. Although blind shaft drilling has been used successfully in many parts of the world, it has not enjoyed the popularity that would seem to be justified except in the Eastern United States coal-mining districts. .

Large diameter raise reaming is an effective means of shaft construction where bottom access is available for cuttings removal. Many raises have been reamed in hard rock to 6 m in diameter, mainly for ventilation shafts. ,/,6m,

Although large diameter shaft reaming has been successful in hard rock, there have been a number of cases where the drill pipe or stabilizers near the reaming head have failed, dropping the reamer to the bottom of the raise. This can have a very negative impact on the time and cost to complete the shaft. /

Many shafts have been constructed using the down-reaming principle where shafts have a bottom access. A small diameter raise is completed first to remove cuttings from the main shaft. This pilot hole raise maybe 1.82 m in diameter. The down-reamers used have been built principally by Wirth Company in Germany. 1.82m//

There have been both the type which follow the raise, and the steerable type, which can ream a raise in an accurate vertical direction even when the raise has wandered off vertical as much as one diameter of the pilot raise.

Tunnelling and drifting is another area of mechanization that can be considered to be developed and available for mining. Tunnelling machines have been used repeatedly in underground mines over a period of more than 30 years. 30

However, the majority of them have not demonstrated the economic success that most tunnel boring machines achieve in the civil engineering industry. One reason for this is the circular cross-section, which is not a shape most mining companies would prefer to use in mine development.

Many mines are not well equipped to manage a mechanized tunnelling machine operation since the management and organization is oriented toward flexible mine development and massive production.

This is a notably different emphasis from civil engineering contractors who have to concentrate on progress at the heading as their sole objective. There have been some important examples of full-face circular tunnelling machines being used successfully to develop underground mines in recent years.

One of those was the San Man uel Mine's decline and level development with a 4.62 m diameter hard-rock tunnel borer in 1993~1995. This was a 10 km tunnel project on three levels. The rock was far from ideal, and required continuous steel ring-beam supports and lagging. 19931995San Manuel4.62m10km

The machine had difficulty with the bad ground in the early stages, but modifications were made to the machine and support systems and the job proceeded at a rate that was much faster than could be achieved by drill and blast development. ,,,.

Roadheaders have been used successfully for many years in medium to soft rocks as has been pointed out earlier. The advantage of roadheaders for tunnel mechanization is their ability to cut varying shapes and to provide the flexibility of cutting short-radius turns and inclines or declines where required. ,..

Another recently developed technique for cutting short crosscuts is the use of a raise drill mounted horizontally to drill a pilot hole from one entry to another and back reaming to approximately 4 m in diameter.4m.

This technique, which was developed in Australia, is being used in other parts of the world as well. Raise drilling has been perhaps the most important success in mechanizing underground excavation. The two principal advantages in raise drilling are speed and safety. .,.

This technology, which was first developed in the early 1960s, started as a technique for drilling a hole from a lower level to an upper level, attaching a reaming head at the upper level and down-reaming to create a raise. 60, ,,.

Most of the mechanization which has been achieved is in the field of transportation, with an increasing use of remote operated load-haul-dump machines, and some use of remotely operated heavy haul trucks underground. ,,.

6. What is currently under development? It has been apparent for many years that under-ground mining has needed a mobile, non-circular tunnelling machine for hard-rock mines. It is essential that such a machine use rolling cutters to fracture hard rock, since no version of a drag pick has been able to overcome the barrier of heat buildup and pick failure.

In the mid-1970s, The Robbins Company began a development, using disc cutters, which they called the mobile miner. Four mobile miner machines have been built since that time, and thousands of feet of tunnels have been driven by these machines, most of it in Australia.2070,

Although the development of this equipment has been progressing for nearly 25 years, these machines must still be considered under development. Current efforts are being directed mainly at hard rock cutters for this equipment, which will provide longer life and lower cost per cubic yard of excavation. 25/

Hard rock cutters are also on the list of products underdevelopment for application to not only mobile miners, but also to full-face tunnel boring machines and raise drills. New materials are being investigated, including composites and new manufacturing methods./,,.

The electronics industry has progressed rapidly in recent years, with instrumentation and sensing of many of a machine's functions and performance features. Monitoring the health and proper operation of many machine features makes it possible to develop planned maintenance down time for underground mining machinery. , ,

A number of projects are underway to utilize more advanced electronic systems. There is a definite trend in developments towards remotely operated equipment including driverless trucks, loaders and conveyors. Some mines are operating raise drills, blast hole drills, and diamond drills with automation packages that allow single-operator, or in some cases, completely operator-free drilling./,,

7. Mechanization that might be developed Underground mining still needs a small, light weight and inexpensive type of tunnelling machine like a mobile miner for hard rock. Many different versions of machines to achieve this objective have been designed and several different types have been built. ,

However, the requirements for this type of equipment are extremely difficult to fulfill. The experience so far with the mobile miner, considering the amount of capital required for that development, does not encourage either mining companies or equipment manufacturers. ,,

Blind shaft drills for high-speed shaft sinking, either from the surface or for subvertical shafts underground, are types of mechanization that could reduce underground development costs substantially. Special machines for in stope hard rock mining for cut-and-fill operations could provide substantial improvements in mine productivity. ,.

Full-face tunnel boring machines for mining applications for boring high speed tunnels long distances underground are needed at numerous locations. These machines must be specially designed to be easily moved underground and assembled at the required development level. .

But they should also be capable of shorter radius turns than most civil engineering tunnel borers, and of handling a wide range of rock conditions.,

8. Will these systems for mechanized mining be developed?

We have already abandoned many developments that have not measured up to the needs of the mining industry. Many of these machines were Robbins developments, but only a certain percentage of these unsuccessful attempts at mechanization are known.

Tunnelling machines for underground mines have been developed since the early 1960s, and most of those developments were not considered complete successes. Among them have been machines with walking gripper mechanisms for continuously propelling the machine forward. 2060

Others had special cutting systems that undercut the rock to create a rock failure under tension. Another was a tunneling machine with two cutters per path except in the center portion, requiring that part of the cutter head to turn at a higher rate of speed than the main cutter head. ,,,.

Other tunnelling machines have been built to utilize high-pressure water jets to assist with the rock cutting, or to cut the rock as the primary cutting mechanism.,

Many different attempts have been made at mechanical shaft boring, both at blind shaft sinking from the top down, and blind boring from the bottom up. These machines have ranged from 4~6 m in diameter. One Robbins shaft boring machine was built for a 6 m diameter size shaft, but was never used. 4m6m6m,

The contractor who had this system developed was never able to convince a mining company that this was a type of machine that they should take a chance with. These unsuccessful attempts at mechanized hard rock excavation represent many tens of millions of dollars in costs for both the mining companies and the equipment manufacturers.

9. Factors influencing the development of mechanization Long-term objectives of underground mechanization are not well matched with short- term fluctuations in the prices of minerals and metals. Large mining companies have seen the need for highly mechanized underground mines to operate at lower costs and to cope with environmental constraints.

Mining companies, from the US, Canada, Australia, and Africa, have provided generous funding in the past to develop advanced solutions for mechanization. However, the world economic environment has imposed extreme pressure on the mining industry due to the short-term cycles and fluctuations of prices for metals and minerals.

This mismatch in economic cycles with the development times required has caused much disappointment and disillusionment. This is the point at which we must do a reality check to see if we are working in an area that can, in fact, produce the solutions that are needed.

We think we perceive an industry need and we can see solutions to some of the problems. The real cost and time to develop major breakthroughs in equipment and mining systems has been seriously underestimated by many in the mining industry and in equipment design and manufacture.

The mining companies have relied on estimates because they sense the reasonableness of a plan to design and build a piece of equipment that may require a development period of perhaps three to four years. The objective is to have a piece of equipment that can have an impact on the mine's profitability at the end of the development. 3~4

The development can be supported by the expectation of profitability of a mine with metal or commodity prices maintaining some degree of stability over the time required to complete the development project. If a development period extends to 15 years or more, the new mechanized product may not be supportable by a mining company whose market has let them down. 15

If the time to complete the development of a useful product extends, the cost to develop it also expands. It has sometimes been the case that the cost overruns for developments involving completely new concepts have run to 200 or 300% of the original budget. Why does this happen? There may be many reasons. ,.200%300%?.

10 Summary and conclusions A mining company with an underground ore body has many incentives to develop a highly mechanized continuous mining system which can reduce the costs, reduce the men at work underground, and improve profitability. ,

However, there are also factors which oppose expenditure for development of a mechanized mining system. Among those is the low cost of production by surface mining systems, which puts heavy pressure on the price of metals and minerals.

Another factor is the existence of high-grade orebodies in locations where the mining can be done with less concern for environmental constraints with lower labor costs. In addition to these factors, the sometimes wildly fluctuating price of metals and commodities makes it very hard for a mining company to take the long range view of their development needs.

With these inhibiting factors in mind, equipment developers and the mining industry must take an objective view about the type of developments that can be supported. We should not assume that long-term support will be automatically forthcoming when the benefits of a development seem so obvious.

A dialogue between the mining industry users of mechanization and the companies who do the development work is necessary. This dialogue must be open and frank including analysis of the benefits and the required payback for any new form of mechanization.The more clearly the objectives and requirements are defined, the better will be the chances of success.

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