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By T. Peter Philip, Erich U. Petersen, William J. Tafuri, Donald M. Hausen, Douglas N. Halbe

Scarcely a month goes by that I or someone else at Newmont Mining or Newmont Gold isn't asked to give a talk on the topic I was asked to discuss today. Investors, financial analysts, geologists, metallurgists, even our government--everybody wants to know what the future holds for gold mining. Well, you're not going to get exactly what you asked for. Today, I'm prepared to focus primarily not on what the future will bring to us, but rather on what the future will demand from us. More than that, I cannot undertake because it isn't within my scope to predict how wise and resourceful everyone in our industry will be in the future. What our future will hold, as I see it, will depend on our--and our colleagues'-- responses to these very real demands. Three critical issues stand out in my mind as to what the future will demand of us in the gold mining industry. And these demands will be for: 1. The very greatest of technical expertise and innovation. 2. The highest order of environmental sensitivity and timely accommodation. 3. Planning, planning and more planning. All of these flow inexorably today from the traditional objective of any mining company--or any company in any business, and that is, to make money. Nothing as I see it, should be undertaken by a geologist, metallurgist or even an environmental department, unless the exercises will enhance profits; and nothing may be ignored which can have consequent damage to the bottom line. Thus, the three issues I've listed for you subordinate themselves to the objective of making money, although at least in the environmental area, it might seem to some that we can only incur additional costs without even a dollar-for-dollar return. I hope to disabuse you today of any such out-of-date notion. Let's tackle the first issue-- Technical Expertise and Innovation. Newmont Gold Company this year is celebrating its 25th anniversary of successful and profitable operations on the Carlin Trend. Carlin in 1961, which is when exploration began on the "Trend" by Newmont, actually may share a lot of similarities with Carlin today. They didn't then know where the gold was and, if they found it, they had one hell of a challenge mining and processing ore at a profit because gold was selling at only $35 an ounce. Today, we know where the current reserves are. But we don't know where our future reserves lie. Furthermore, we don't know exactly how we're going to mine them, and, as everyone here knows too well, we don't know what the optimum metallurgical treatment is, even if we can find and mine them. And all that despite the abundant level of modern experience and skills within the current generation of mining companies, and the fact that, even taking inflation into account, gold sells at a higher price today than in 1965 when Carlin began operations. But, of course, I'm telling you what you already know.

Jan 1, 1990

By C. Williard

Computer based mine monitoring and control systems represent a relatively new technology to be applied in the U.S. mining industry. While computer assisted engineering, design, and planning have been accepted as tools for specific technical and engineering jobs within the industry, integrating mine-wide monitoring and control systems into mining operations has been slow. This paper reviews the state of the art of mine monitoring and control systems and provides insights into future trends and developments.

Jan 1, 1988

By Frank T. Wheby, Edward M. Cikanek

A computer performs all logic and computations customarily done by hand in preparation of engineers' estimates or contractors' bids on tunnel-shaft systems. The program described is based on construction methods, work forces and equipment selections corresponding to the current state-of-the-art of rock, soft ground and cut-and-cover tunneling. The program contains logic to permit estimates of cost of complicated tunnel-shaft systems; it is not necessary to input quantities, as the program calculates those from the tunnel design that is internally generated. In any estimate, the program bases its cost computation on user-input requirements and site conditions, such as tunnel shape and size, shaft depth, ground characteristics, construction methods, and other factors. To provide great flexibility, the user of the program is provided with options for accepting designs built into the program or overriding these designs by his own inputs. An illustrative example is presented.

Jan 1, 1974

By J. W. Lowry

After years of processing copper porphry ores, the Ray concentrator of Kennecott Minerals Company installed a concentrate regrind mill in its flotation circuit. The first cleaner concentrate is reground rather than the usual rougher concentrate. An additional cleaning of the reground product yields an increase in copper content of the final concentrate and a significantly lower insol content. The desired goal of decreasing the energy requirements for smelting the concentrate has been achieved.

Jan 1, 1980

By W. K. Fletcher

As part of an ongoing programme on behaviour of heavy minerals In streams, the dispersion of Au as free gold (Day and Fletcher, 1987), Sn in cassiterite (Fletcher et al, 1987) and W in scheelite (Saxby and Fletcher, 1987) have been investigated downstream of mineralization. The studies of Au and W were undertaken, in British Columbia and the Yukon Territory, respectively, in streams that are strongly influenced by spring snowmelt floods. Sn was investigated under tropical rainforest conditions in Peninnsular Malaysia.

Jan 1, 1988

By André Vervoort

The roof behaviour in room and pillar panels during the development of roadways and the subsequent pillar extraction was monitored underground and numerical simulations were conducted. For several underground sites, a satisfactory, correlation was found between underground measurements and three-dimensional numerical simulations using a boundary element code in the linear elastic domain. However, to simulate bed separation, and roof block collapses more complex models were required, of which examples are presented.

Jan 1, 1992

By D. Royston

The use of large face angle shell lifter-liners in combination with wider lifter spacing has grown in recent years, especially in large SAG mills. The claimed benefits are reduced ball on liner impact, leading to increased liner lives and less ball breakage, and both reduced packing and improved ball-on-charge impact, leading to improved mill performance. This review covers available published data on several mill sites and aims to quantify the observed benefits.

Jan 1, 2003

The major stages in the life cycle of a tailings facility include site selection, impoundment de-sign and construction, operation and closure. Optimum management of these stages requires an integration of all legal, engineering and environmental aspects in order to improve safety and minimize future potential risks for humans and the environment. This paper discusses the main factors involved at each stage and focuses on the stability considerations of the impoundment facility.

Jan 1, 2002

By D. T. McMurray

INTRODUCTION Shabanie mine, situated some 180 km east of Bula¬wayo, has been a producer of chrysotile asbestos for more than 50 years. The ore bodies occur in serpentinized dunite, which overlies talc-carbonate schist. A zone of relatively competent rock of varying thickness occurs between the schist and the ore bodies, which are gen¬erally less competent. The hanging wall of the ore bodies is economic, and the hanging-wall serpentine carries a variable subeconomic amount of fiber. It is important to note that, in general, the ore body competence is less than that of the foot and hanging-wall formations. Historical After surface operations ceased, cut-and-fill stoping was used to win ore from underground; this was success¬ful until the increasingly stoped-out area caused insta¬bility in the stope pillars and back. Consequently, dur¬ing the early 1950s, a gradual change to cave-mining methods was made, the ore being won by hand lashing in drawpoints, situated in the basement of the stope blocks, and passed through orepasses under gravity to the haulage level some 13 m below. About this time, interest was focused on the sub¬level caving method in use in Swedish iron ore mines: it was felt that it might be applied economically to the Shabanie ore bodies. Accordingly, in 1958, an experi¬mental stope block was laid out in which sublevel inter¬vals and extraction tunnel spacing were 9 m. The tun¬nels (ring drilling drives) were oriented on strike-in contrast to the Swedish system, in which crosscuts that retreat from hanging to footwall are used. The advantages of the method were quickly appre¬ciated by the operating personnel and, despite the in¬evitable teething troubles pertaining to the introduction of any new mining method, it was not long before sub¬level caving was providing a high proportion of the mill feed. The disadvantages also became apparent at an early stage, however, and, from that time to the present, continuing modifications have been made to mining lay¬outs in an effort to improve ore recovery. GENERAL DESCRIPTION OF METHOD The mine is served by a vertical hoisting shaft, in which two skips, a man cage and a service cage, provide adequate capacity for production requirements. The rock hoist is a Ward Leonard control hoist, in which two electric motors drive a common gearbox. The man winder is driven by an a-c motor. Several auxiliary shafts provide secondary egress and intake and return ventilation. Main haulage levels are above (Fig. I a and b). Blasthole fan patterns are drilled by drifters of 100 mm bore, drilling 41-mm holes; when a sufficient strike length has been drilled, a slot is cut in the upper¬most sublevel and the rings are broken into the slot. Initially, a limited tonnage is drawn, since it is essential to ensure that the hanging wall caves behind the retreat¬ing stope face. Once this has been established, maxi¬mum tonnage can be drawn, as described later in this chapter, under the heading "Draw Control." The broken rock is loaded by 0.14 and 0.20-m3 load¬ers into cocopans (rocker-dumping type of tipping truck), which are hand trammed to orepasses, discharg¬ing on the haulage where 11-t electric trolley locomo¬tives haul 3.95-m3 Granby cars to the main shaft bins. As is evident from Fig. 1, the layout is simple, the block is brought rapidly into production, there is a high degree of selectivity and flexibility, and the result is a low-cost high-productivity mining method. DEVELOPMENT Main haulages are developed at 3.2 x 3.2 m, and once the service winze connections have been completed the development of the sublevels is undertaken. The footwall drives are cut first, to obtain access to the block. These ends are of the standard section, 2.4 x 2.8 m, and from them crosscuts at intervals of 70 m are driven through the ore body to the hanging wall. These crosscuts are used to supplement the geo¬logical information previously obtained from diamond core drilling, and they provide additional and more de¬tailed data on fiber percentages and lengths, structural features, and other relevant criteria which are used to build up the geological assessment of the area and to classify it in terms of the geomechanics rock classification (Laubscher and Taylor, 1977). The crosscuts also allow the necessary orepasses to be sited conveniently so that tramming distances from the loading points are not excessive. Development Drilling Once the skeleton development has been completed, the extraction headings are developed at 2.4 x 2.4 m as shown in Fig. 1. Standard development practice is to use crews of a machine operator and his helper, equipped with air-leg mounted jackhammers, to drill rounds of 1.8 m with integral tungsten carbide tipped drill steel. The round drilled is a normal drag round, as shown in Fig. 2, but considerable attention is paid to the drilling of the perimeter holes to use effectively the

Jan 1, 1982

By Steve Kral

The list of environmental issues facing industry in general, and the mining industry in particular, has placed greater emphasis on the concept of risk assessment and risk management. In informal terms, risk can be defined as the chance of injury, loss or damage. More formally, it is defined as the probability of an occurrence and its consequences. In simple terms, risk assessment involves three questions: What can go wrong? How probable is it to go wrong? If it goes wrong, what are the consequences? Experts on the subject of risk assess¬ment and management met in St. Louis, MO in October 1992 to discuss the extensive and innovative technology that has been developed in this arena. Each agreed that a consistent framework can be used to approach risk assessment/ management considerations in siting and design alternatives, as well as when considering financial aspects of mine development. And the environmental planning process for mines, as well as planning for operation through closures, will rely more heavily on risk assessment and management techniques. Risk assessment is a tool to assist engineers, scientists and managers make better, defensible operational decisions. A realistic and probabilistic risk analysis, coupled with a sound financial model, can combine a large set of alternatives and criteria to arrive at a defensible decision. Organizers of this regional SME conference believe that mining professionals should become fully conversant with risk assessment techniques and approaches because this arena provides opportunities to develop more rational decision-making techniques. Current health risk assessments rely heavily on Environmental Protection Agency (EPA) approaches. Several speakers and papers show how this approach has been applied to a variety of topics. Two major advantages come forward when applying risk assessment techniques to environmental clean-up options for contaminated sites. They are the selection of practical options and cost-effective alternatives. A probabilistic risk assessment provides results that can be directly related to clean-up costs. It has been shown that small reductions in risk are obtained for large increases in cost after a certain threshold value is reached. A preferred, practical clean-up alternative that provides permanent solutions can be selected based on a probabilistic assessment. Here are summaries of some of the papers presented at the meeting.

Jan 1, 1993

By G. W. Luxbacher

Coal mine infrastructure is rarely designed solely on the basis of ventilating the underground workings. Instead the optimization of a mining sequence, the minimization of coal quality variation, reduction of coal losses by adapting to property boundaries and geologic structure (seam inclination, roof conditions, coal thickness, etc.) or other similar considerations have formed the objective for mine plant design and layout. Infrastructure development may also reflect a desire to maximize production early in the life of the mine or to permit flexibility in mining according to market conditions. Requirements for coal mine ventilation, established by the 1969 Coal Mine Health and Safety Act, have mandated changes in the traditional concepts of mine plant design in the United States. Mines, in operation prior to the passage of the Act have experienced severe limitations when attempting to adapt the existing mine infrastructure to meet the requirements of the law. In addition the increased quantities of air required, velocity limitations on trolley haulage and belt lines, the establishment of separate intake escapeways and gob area ventilation have com- pounded the inherent complexity in planning mine ventilation systems. Past practices in mine ventilation planning and design are no longer adequate. Given the complexity of today's ventilation systems, effective planning and design approaches are required. As such, the interrelationship between the overall coal mine plant design and ventilation system design is examined. An approach to ventilation system design constrained by global considerations of mine plant design, is presented. The proposed approach is, however, applicable to the design of new mine ventilation systems as well as to the modification of existing systems.

Jan 1, 1980

By R. E. Nelson

The Alton Coal project, located in south-central Utah, lies at one point just over six miles from Bryce Canyon National Park. This region of the southwestern United States has been called the "Golden Circle" of national parks and monuments. Can a mine be inserted into this region so that it does not intrude on this spectacular landscape? The Alton Coal Project is a proposed surface coal mine designed to serve as the fuel source for the Harry Allen Power Plant, a 1,000 megawatt generating station planned for a site 25 miles northeast of Las Vegas, Nevada. The mine and the power plant will be connected by an underground pipeline through which coal will be transported in slurry form.

Jan 1, 1988

By William K. Burriss

Computer technology was applied to solve three problems in the selling of certain industrial minerals to the glass and foundry industries. The computer solutions provide for better service to customers and have helped increase sales. II. Summary Electronic data processing techniques were applied: 1. To automatically and continuously "trace" rail car shipments of bentonite. 2. To aid our sales people in recommending to glass plant purchasing agents which of several possible feldspathic materials is the best value at any of about 100 glass plants and to give guidance on the amount of value difference. 3. To help in locating plant sites for three blending or pre-mixing stations to serve the foundry industry at minimum cost and with maximum tonnage and maximum profitability.

Jan 1, 1968

By James E. Brewer

Procedure for approval by the U. S. Army Corps of Engineers of a new source of aggregate is in three phases. Phase 1 consists of an investigation of a quarry or proposed quarry by district geologist and laboratory geologist and/or petrographer. The quarry face or suitable outcrop is logged in detail or, if exposures are poor, cores may be taken to determine whether further investigations are warranted. Phase 2 consists of thorough laboratory testing. Cores and crushed material are subjected to a number of acceptance and quality tests for soundness, absorption, abrasion, reactivity, and other properties. Petrographic analysis is also made. Phase 3 is a physical and economic study of the site and involves determining quantity of stone avail- available, amount-and character of overburden, condition of haul roads and distance to rail shipping point, plant flow sheets and capacity, aggregate sizes produced, and approximate price of material at plant.

Jan 1, 1966

By H. V. Scotland III

Lafarge Corporation's Texas Quarry, in Baltimore MD, achieved a substantial expansion of pit reserves by removing an inactive underground mine. The day lighting program, designed, and completed in 1997, open pit mined more than 400 meters of room and pillar workings which were originally developed to recover high brightness Calcium Carbonate. The project proved to be a challenge throughout its course as the pit plan was modified and successful daylighting techniques were developed to remove the mine without adversely affecting the safety of the operation, quality of the stone recovered, or negatively impacting the surrounding community. The design parameters and techniques developed and implemented at Texas may prove of interest to other operators as they are faced with daylighting opportunities. This article will detail the challenges we faced and the solutions which made the project a success.

Jan 1, 1999

By Courtney Black, Paul F. Ziemkiewicz, Eberhard Werner, Matthew Daly, Joseph J. Donovan, Jeff Frazier

Injection of alkaline waste-lime slurry was performed at a West Virginia surface coal mine site, to attempt neutralization of acid springs by an alkaline recharge method. Deep trenching (>5 m) using an excavator yielded the most effective injection into the aquifer. Water from two springs, 90 m from the deep trench, showed 70%-80% reduction in acidity in response to injection. Neutralization persisted >170 days after treatment, with pH between 5.1-5.7 and metal acidity from 25-60 mg/L. A minor fraction of lime introduced was consumed. The sustained neutralization is attributed to reaction of acid water with subsurface lime, entrained below the wafer table by macropore infiltration. Characteristics of groundwater transport are critical in determining recharge structure location.

Jan 1, 2000

By Ralf Vergeiner

The most famous landmark of the city of Graz (Austria) is the clock tower on the castle hill. An underground chamber was built as a multifunctional structure beneath this landmark. The required structure was designed as cavern. The overburden to the clock tower in the north side of the cavern was only 30 m. To allow access from the city to the chamber and the clock tower, a vertical shaft was built near the cavern. Rock excavation was by drill and blast method. The pilot shaft was made by the raise-boring method. Because the location of the building site was in the center of Graz, special care was taken to minimize deformations and vibrations so as to protect surrounding buildings.

Jan 1, 2001

By Irwin R. Higgins, Joseph C. Milbourne

The selection of a suitable nitrate removal process depends on a variety of site-specific chemical and environmental issues. The dominant technologies for nitrate removal include biological denitrification and continuous countercurrent ion exchange. The decision to apply either of these technologies, or both together, depends on the nature of the waste water to be treated. Factors that affect the selection of the biological system include the feed composition and feed temperature. Ion exchange nitrate removal systems ere less sensitive to the feed composition but require disposal or destruction of the concentrated pregnant eluate. The paper discusses Tetra's continuous countercurrent ion exchange technology (CCIX™) and fixed film biological reactor, Denite®. The treatment of the ion exchange pregnant eluant is also discussed.

Jan 1, 1995

By A. Yehia, J. S. Hu, J. D. Miller, M. Misra

Fluoride activation has been evaluated by Hallimond tube flotation of collophanite in terms of fluoride concentration, conditioning time, pH, and temperature. The results reveal that efficient oleate flotation of collophanite can be achieved by fluoride activation. Experimental results of fluoride adsorption by collophanite suggest that, at low fluoride concentration, a fluoroapatite-type compound may form on the collophanite surface by chemisorption of fluoride ions at calcium sites. At high fluoride concentration, calcium fluoride appears to form at the collophanite surface involving a surface precipitation phenomenon. The formation of CaF2 on the surface of fluoride-treated collophanite is further substantiated by the FTIR spectroscopic measurements, which suggest a metathetic exchange with phosphate from the collophanite lattice during the surface precipitation process.

Jan 1, 1988

By J. C. Weimer

The goal of Bethlehem's mining research program is to improve both the safety and productivity of our mines through the use of new equipment, new technology and new mining methods. Although we can all agree on the value of such goals, achieving them can be a costly, time-consuming and sometimes frustrating experience. However, the potential benefits of lower costs per ton and better safety in an increasingly more stringent and confusing regulatory environment make the expended effort worthwhile. At Bethlehem we feel that the mining companies are in the best position to determine the needs of the industry, and coal companies have the incentive as well as mine sites at their disposal for testing. Therefore, the mining industry should be leading the research effort

Jan 1, 1979