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By L. Henry Smith, David C. Arthur

The Williams Mine is Canada's largest gold producer, with annual production of 14,000 Kg (450,000 ounces) from 2,300,000 tonnes of ore. Highly mechanized and automated underground mining practices are employed in order to achieve and maintain high levels of productivity and minimize costs. The Mine Ventilation System is modified to include a new Vent Raise and Variable Pitch Vane-Axial Fan. This addition allows several fan installations underground to be decommissioned. A substantial net savings in installed horse power is achieved. Heating costs associated with underground ventilation air are a significant portion of mine operating costs. Air heating costs are substantially reduced by recovering heat from upcast exhaust air, mine water and compressor cooling circuits. This waste heat is used to supplement propane fired air heating systems for underground ventilation air. An additional benefit is the availability of a heat sink for summer cooling of the compressors. System design, energy savings data and payback calculations are presented.

Jan 1, 1997

By Robert F. Hauck

This chapter discusses a new technology for computer control in open-pit mine operations: the real time automatic dispatching of manually driven trucks to shovels. The monitoring of truck activity is accomplished by detection of local radio signals. Computer-operated directives are communicated to drivers by remote controlled digital display units inside the truck cab. The production objective is to maximize tonnage in a cost effective manner. The problem is formulated in the appendix and the solution method is briefly described. Side conditions such as maintaining delivered ore grade aims, balancing waste to ore volumes to keep within stripping ratio tolerances, and meeting production rate requirements temporarily established for certain shovels are also discussed. Experience with a developed event- to-event simulator applied to analyses of several North American mining operations using this technique is summarized. Complete systems employing this technology are now under- going installation at mine sites in Canada and the United States.

Jan 1, 1979

By Jack W. Eloranta, Michael J. T. Orobona, Peter R. VanDelinder

Ore blending for process optimization is becoming an increasing factor for managing cost and productivity. Economic mining and processing a very low value ore in an extremely competitive market results in constant cost-cummng initiatives. The inherent conflict between the lowest possible mining cost and the lowest possible milling cost is reviewed here in the context of blasting for autogenous mills. Iron ore blending focuses on a number of properties-liberation values, weight recovery and concentrate silica being the most important. Other chemical and metallurgical factors are also commonly controlled. Recent research has fueled an emerging interest in blending on physical ore properties as well. Fully autogenous mills rely on the large, competent fraction of crushed feed to act as grinding media. Previous test work indicated that Hibtac mills require specific amounts of 6- to 10-inch ore. High recirculating loads require a steady influx of large rock fragments. Blast designs, therefore, are presently characterized by wide patterns and low powder factors. Current efforts are aimed at improving mill throughput while reducing overall energy costs. Based on research and published case studies and the advent of optical measuring devices, Hibbing Taconite Company has embarked on a blast optimization program to identify optimum mill feed and to design blast fragmentation goals for each geological unit and each mining area. This paper outlines the preliminary findings of an ongoing, broad-based team effort which requires close cooperation of geologists, mine engineers, crushing and milling personnel. Three specific areas of investigation are reviewed: I) Historical relationships between powder factor and mill performance, 2) Blast fragmentation modeling using the Kuz-Ram model, and 3) Drill

Jan 1, 2004

By R. W. Barbaro, J. M. Mutrnansky

This paper presents a nonlinear integer goal programming model that optimizes a mineral production schedule while considering the penalties and bonuses based on quality variations in the final product. It involves five coal quality goals plus a profit objective in its formulation and uses the weighting method of goal programming for a solution. The goals to be sought involve the sulfur, ash, heat content, moisture content, and ash softening temperature of the blended coal product. The model is linear in its handling of most of these goals but uses a piecewise linear integer formulation for the sulfur and heat content bonus and penalty schedule. The model is applicable to any mineral product blended from several different sources and subject to a varying price dependent on blended product quality or qualities. However, it seems to be most pertinent to optimizing production schedules for coal deliveries to power plants. Accordingly, the model is applied to a hypothetical coal production problem where multiple coal mines are operated to supply a final blended product to a power plant. In this example, the price paid for the coal is assumed to be a function of five of the most important coal qualities. The problem is solved as a direct function of the coal supply contract, thus removing the necessity of determining the weighting coefficients on a subjective basis.

Jan 1, 1987

By David A. Lindsey

In this paper, we present a physiographic classification of gravel deposits, identify some field measures of aggregate quality, and describe sampling strategies for mapping aggregate quality in the Front Range Urban Corridor of Colorado. Gravel occurs in four types of deposits along the Front Range of Colorado: (1) piedmont alluvial fans, (2) high dissected terraces, (3) high (continuous) terraces, and (4) floodplains and low terraces. The four deposit types are the basis for definition of gravel-deposit models, which differ in geologic environment, deposit characteristics, deposit size, environmental impacts of mining, and post-mining use. Of the four types, floodplains and low-terrace deposits have been exploited most for gravel. High terraces also have been mined. Deposits of high dissected terraces and dissected alluvial fans have produced minor amounts of gravel, mostly for use as local fill. Studies to identify useful field measures of aggregate quality and to determine the appropriate scale for sampling were conducted on gravel deposits beneath the flood-plain and low terraces of the South Platte River north of Denver and the Cache la Poudre River between Ft. Collins and Greeley. Gravel deposits of the South Platte were selected for study because they represent the last major resource of gravel for aggregate in the Denver metropolitan area. The Cache la Poudre valley is the primary source of gravel aggregate for rapidly urbanizing areas around Ft. Collins and Greeley. Of all the field measures of gravel quality, the most important is particle size. Various parameters that measure particle size were investigated, but the easiest to determine, and the most useful to the aggregate industry, are measures of the proportion of coarse sizes. Particle size varies widely in gravels of the urban corridor. Gravel lithology, particularly the presence of deleterious particles such as reactive volcanic rocks and decomposed rocks, must be determined to assess aggregate quality. Studies of South Platte and Cache la Poudre gravels have not revealed large proportions of deleterious lithologies. Studies of particle shape revealed only small numbers of physically weak shapes in both the South Platte and Cache la Poudre gravels. Particle shape does not appear to vary from place to place in the gravels. Rounding, or the ab¬sence of angular corners, may play a role in the tendency of loose gravel to yield under load. South Platte and Cache la Poudre gravels are rounded, and rounding tends to increase upstream. Before the quality of gravel in a valley can be assessed, the stratigraphy of the gravel must be known because it affects sample design. If only a single gravel layer is to be studied, only the thickness of the gravel must be known before sampling. If, however, more than one layer of gravel-distinguished by particle size, sorting, or lithology-is present, sampling must take into account the thickness and distribution of each layer. For example, three gravel layers of different particle size underlie the floodplain and low terraces of the South Platte. The tributary Cache la Poudre, on the other hand, contains gravel layers that can be distinguished only locally and vary slightly in particle size. Sampling experiments were conducted on gravel bars in the South Platte River and in gravel pits on the floodplain and low terraces of the South Platte and Cache la Poudre Rivers. Experimental results indicate that, even where sample error is large, regional and stratigraphic variation may be measured if it is large relative to sample error. Using vertical trench samples weighing an average of 40-90 pounds, down-stream decrease in coarse particle size was mapped for Cache la Poudre gravel, and differences among superposed gravel beds were measured for South Platte gravel.

Jan 1, 1999

By William Highton

If the economic situation in the Western World evolves on a path similar to that of the past decade, then we Mining Engineers must accept that one of the major cost factors in the production of deep mined coal is going to be that of labour. Whilst not trying to over-simplify matters it does appear that one of the ways of maintaining acceptable coal costs is by obtaining more coal without increasing manpower. One such way could be an increase in the use of the retreat method of mining. The paper theorises and illustrates case studies to show that as the Mining Industry extends the use of Longwall retreat mining systems in coal seams where the risk of spontaneous combustion exists, then the use of bleeder entries should be questioned. In addition to the spontaneous combustion risk, bleeder entry systems where the ventilation flow is not fully controllable cannot be construed as a safe and reliable method of controlling high rates of methane emission. These two major aspects alone should be sufficient ground for Mining Engineers to re-consider the practice of using bleeder entries. An alternative "The Back Return System" appears to offer most of the advantages for controlling the environment, without the disadvantages of the other system.

Jan 1, 1980

By A. S. Speirs

Over the last few years, the never-ending search for mineral wealth has taken the exploration efforts of Canadian mining companies further and further into the High Arctic and isolated locations where regularly scheduled transportation and communication facilities are nonexistent. Names such as Black Angel, Nanisivik, Asbestos Hill, New Quebec Raglan, Rabbit Lake, and Arvik are today frequently mentioned in mining publications. Twenty years ago, mining in these locations was unheard of, mainly due to logistic problems. However, improvements in the design and use of helicopters, STOL aircraft, and icebreakers in northern areas have helped to overcome these problems, making these locations more attractive to mining companies. Since 1969, when Redpath completed its first Arctic project at Texas Gulf's Scrathcona Sound property on the northern tip of Baffin Island, Redpath has been actively involved in contracting and engineering projects in three general areas: the High Arctic, Ungava and Greenland. A map showing some of these projects is shown in Figure 1. In these areas, permafrost conditions exist from a depth of 274 metres in Ungava to a depth of approximately 610 metres in the Little Cornwallis Island area, with rock temperatures ranging from -5°C to -13°C. Outside temperatures range from a low of -50°C in the winter to a high of 21°C in the summer. High winds in the winter result in wind chill factors lower than -73°C

Jan 1, 1980

By Ernst P. Hall

As a scientist and an engineer whose responsibilities include the consideration of air pollution and its control, I am frequently called upon to answer variations of two basic questions, These questions may I be set forth as: (1) How much air pollution does the coal industry cause? (2) How serious is the air pollution problem to the coal industry? At first these questions may seem elementary and almost trite, but serious consideration of them will show that they are technologically involved and I further complicated by the subjective base to which they must be evaluated.

Jan 1, 1963

By L. Shevenell

Nevada now has, or will have, 35 pit lakes resulting from open-pit mining below the water table. State regulators are requiring that the ultimate pit lake water quality be predicted as part of the permit application process. Water balances/pit lake filling rates must be esti¬mated in support of the geochemical modeling. In Nevada, analytical and numerical methods have been employed for the study of pit lakes. In the current work, analytical solutions are investigated for one pit lake, the Getchell south pit lake, which previously filled be¬tween 1968 and 1982 during a hiatus in mining. Water levels vs. time are available for this lake and these data have been fitted with a hyperbolic curve. This water-level-vs.-time curve was used in simple water-balance computations to find the net inflow rates by forcing computed water levels and volumes to match those of the known water levels and volumes through time. The model described here provides realistic volume fluxes into and out of the lake on a monthly basis as the pit lake filled.

Jan 1, 2000

By H. L. Ehrlich

Modes of microbial attack of metal carbonates, metal silicates, metal oxides and metal sulfides are summarized. The current status of microbial redox mechanisms, whereby metals in metal oxides and sulfides are mobilized, is discussed. Opposing theories of a single mode of attack involving interaction with a microbially produced reductant or oxidant in the bulk phase and of dual modes of attack involving a reaction requiring physical contact between microbe and mineral surface on the one hand and microbial production of a reductant or oxidant in the bulk phase that reacts with the mineral on the other hand are considered. No one mode when finally completely unraveled should be expected to fit all cases. Some biochemical, electronmicroscopic and spectrophotometric approaches for elucidation of missing details of different modes are suggested. Key words: Bioleaching, Biobeneficiation, Metal mobilization

Jan 1, 2003

By Raphael G. Kazmann

Water occupies a dual role in our industrial society. It is the indispensable raw material, essential to life itself. It is equally an industrial nuisance, interfering with the production of industrial minerals, making construction difficult, flooding valuable land, and generally producing problems because it is in the wrong place at the critical time. The legal position of water as a nuisance, and the counter measures to be taken, have been well established procedures for determining the responsibility for damage caused by water, and the organization of drainage districts and flood control and levee districts have been legally tested many times. Thus there is rather adequate legal doctrine concerning water, the common enemy. But recently efforts have been made to regularize the position of water as a useful, industrial, commodity. Such laws are not new to the West, where the doctrine of appropriation for beneficial use is slowly becoming the water law. Elsewhere the University of Michigan has produced a "model" water law and efforts are being made to induce all of the states to use this law, or a slight variation of it, as the basis for legislation. There are many serious criticisms of the proposed "model"-law, and the writer strongly opposes many of the provisions. But the fact remains that water is, in itself, so useful and essential that laws have been, and will be, passed to insure the orderly development of our water resources and to prevent waste. The, most important aspect of these "water-use" laws is that, wise or unwise, the existing laws and the proposed laws have been "water oriented". "Water oriented" means that it has been tacitly assumed that the beneficial use of water, either surface water or ground water, is the overriding consideration.

Jan 1, 1960

By Håkan Stille, Kjeld Boye-Møller, Lars Lundström

BACKGROUND Forsmark Power Station is a nuclear power plant under construction at the Baltic abt 120 km north of Stockholm. Investigations on the Site were started in 1969. Areas were reserved for a maximum of 6 units of which the buildings for two of them, Unit 1 and 2, were nearly finished in 1976, when the investigation for Unit [3], here presented, was carried out, cf Fig. 1. [ ]

Jan 1, 1979

By R. A. Jankowski

The US Bureau of Mines (USBM) conducted a series of laboratory tests to investigate the effectiveness of using a flooded-bed scrubber with exhaust ventilation in deep-cut faces. An experimental test program to determine the impact on respirable dust levels resulting from changes in face airflow, curtain-setback distance, operator positioning and operating parameters of the external spray system on the miner was completed. Gravimetric sampling was conducted in the immediate return and at three sampling locations on the off-curtain side of the entry. Statistically significant differences in dust levels, on the order of 0.5 to 1.2 mg/m3, were observed between specific sampling locations and changes in several test parameters. Dust sampling results indicated that a flooded-bed scrubber and exhaust ventilation can be a viable dust-control system for extracting deep cuts up to 12.2 m (40 ft) in length. The impact on methane was not evaluated.

Jan 1, 1998

By Mulong Yu, Yosry A. Attia

Beneficiation of high magnesium Florida phosphates requires ultrafine grinding to liberate the dolomite (the main source of magnesium), and a separation process capable of dealing with ultrafine sizes such as selective flocculation. The objective of this study was to investigate the feasibility of separating dolomite from apatite ultrafines by selective flocculation. To achieve this objective, selective polymeric reagents to either dolomite or apatite must be first designed and synthesized. This challenging task was accomplished by carefully selecting complexing/chelating agents which are selective to either the Ca or Mg ionic sites on the minerals, and incorporating these reagents into the structure of long chain water soluble polymers to obtain either selective flocculants (with high molecular weight, MW, polymers), or selective dispersants (with low MW polymers) to either the dolomite or the apatite particles. Synthesis and testing of these polymers on individual and mixed mineral slurries, and on a sample of natural high magnesium phosphate ore, have been attempted and the results are described in the paper. The preliminary results showed encouraging signs for the feasibility of selective flocculation separation of dolomite from apatite.

Jan 1, 1993

By G. Almgren

With the exception of sublevel caving, the most common method of underground mining in Sweden is the "cut-and-fill" method. It is normally used for mining non-ferrous metals , and' is used extensively in the complex sulfide ore mines of the Boliden Company in north and central Sweden as well as the mines of the STORA and Vieille Montagne Companies in central Sweden. All in all, the cut-and-fill method is used in 13 of Sweden's 45 mines. As the mines are relatively small, the volume of ore mined by this method represents only about 5 % of the total ore production in Sweden. The commercial value, however, is much large than this percentage would imply. The production volumes and grades of some typical mines are shown in Table I. As seen, when rated internationally, the grades are comparatively low. The prices are set according to ?international metal prices? as dictated by the London stock exchange, and in lieu of governmental support, rational management methods are critical in order to achieve satisfactory profit.

Jan 1, 1975

By Frank F. Aplan, Edward C. Dowling, Richard R. Klimpel

Several series of time-instantaneous samples were taken on a cell-by-cell basis in the flotation circuits of the Pinto Valley, AZ copper concentrator. These samples were used to calculate mass flow rates throughout the circuit using standard, deterministic metallurgical formulae and also a variety of more statistically oriented techniques. Because of the magnitude of the errors associated with the individual cell samples, the standard metallurgical formulae are not sufficient. Consequently, it is necessary to utilize some type of statistical technique capable of distributing the individual cell sample errors in such a way so as to provide a physically useful mass balance for the entire circuit. This paper explores the use of linear and least squares programming as one technique to providing credible mass balance calculations. For linear programming this was done by distributing the error using two different criteria involving specific linear programming formulations: least absolute sum minimization (which assumes an underlying double exponential distribution error structure) and minimax (which minimizes the maximum absolute deviation and assumes an underlying rectangular distribution error structure). These results were then compared to the more standard formulation of minimization of the sum of least squares which assumes an underlying normal distribution error structure. The least absolute sum approach was particularly attractive due to its simplicity of use and the ease in which repetitive calculations can be done with no user intervention.

Jan 1, 1990

By Patrick A. Ley

Maintaining, managing and manipulating large quantities of geologic data can be a very costly and time-consuming process. The use of computer-based methods can provide some relief to the problems of editing, displaying, and interpreting spatial geological data. ENCORE is a system designed specifically for coal orebody modeling and reserve esitmation where the geologic data is stored on a large mainframe computer and is accessed from a local work station for editing, manipulating, and producing various reports and high-quality engineering maps. The ENCORE system was designed for use by the geologist or mining engineer with little or no computer background and, additionally, it was designed to provide the geologist or mining engineer enough flexibility to be able to select the appropriate methodology for the orebody being analyzed. The various analysis tools incorporated into ENCORE can significantly increase the professional's productivity without burdening he or she with the need to understand the details of the internal computer language.

Jan 1, 1982

By D. Duvris

The main objective of this work was to quantitatively investigate exhaust emission levels relative to maintenance (service) intervals during the operation of diesel-powered equipment at an underground bauxite mine in Greece. Such emissions depend on a great number of parameters, including the type of engine (technology) and its tuning, the type of work performed (as related to the engine workload), the suggested maintenance intervals, the altitude, the temperature and humidity of the atmosphere in the underground mine, the properties of the fuel and the operator's training and experience levels. The necessary ventilation quantities were calculated based on exhaust gas-concentration measurements and site-specific relationships between pollutants and adjusted air-quality indices. Diagrams comparing the necessary and recommended airflow for several equipment groups, featuring two engine types and different maintenance intervals, are presented.

Jan 1, 2000

By Fouad Faraj, Julian M. Ortiz

Within the natural resource industries, there is an increasing amount of data and number of variables being recorded when sampling a site. This has made multivariate geospatial datasets more difficult to analyze, in particular the definition of estimation or simulation domains used in geostatistical analysis. Establishing these domains is typically the first step for any subsequent geostatistical workflows or modeling. Domains are traditionally established using categorical data such as lithology, mineralization, or alteration from geological logging and are aimed at identifying distinct populations with particular geological, spatial, and statistical features. The manual logging process is time-consuming and costly but is required because defining geologically homogenous volumes is crucial for the planning, extraction, and processing of natural resources. Classical clustering methods have aided in analyzing the multivariate datasets, but the resulting clusters from these methods do not correlate well with geological logging and do not allow practitioners to input their knowledge of the domain in the clustering process. In this work, a simple unsupervised classification workflow is presented which allows the practitioner to input domain knowledge by selecting relevant variables to cluster reasonable geological domains. This can be used as a tool to aid the manual logging procedure or as a tool to establish domains for different uses such as defining zones with different rock hardness distributions which allows the corresponding volumes to be sent to appropriate mills for efficient mineral processing. The performance of the workflow is assessed on a mining dataset using the geochemical information and validated with the geological logging.

Apr 16, 2021

By S. J. R. Lowrie, J. S. Edwards, A. D. Jones

A small scale model has been constructed to simulate air and gas flows on a full scale retreat longwall coal face. Scaling relationships were derived to define how the main aerodynamic properties of the full scale could be preserved in the small scale model. These scaling requirements include: a minimum value for the Reynolds number for the flow on the face in order to maintain turbulent flow with a constant non-dimensionalised coefficient of turbulent dispersion; a constant Richardson number to maintain similitude for the formation of layers of buoyant gas; scaling of the permeability of the waste so as to obtain the same proportion of seepage flow through the waste; pressure gradients due to the ventilation and to the density difference (between the air and the gas layer) were kept in proportion; and in the waste, the relative contributions of inertial dispersion and molecular diffusion were approximately in proportion. The complementary roles of computational fluid dynamics (CFD) and aerodynamic scale models for simulating mine ventilation are discussed. The physical model is described and an example presented of simulations of the effect of changes in mining condition on the effectiveness of gas control in retreat longwall coal faces.

Jan 1, 1995