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By John Jonkman

Two major changes occured during the last 5 years in the applications of computers. First, the cost of computer equipment decreased drastically in an era of high inflation. Second, technological breakthroughs in hardware and software have been applied successfully so that the average person can successfully utilize the computer without having to be a computer expert himself. The mining industry has recognized that computing technology has evolved to a point where it can be applied successfully to assist in improving productivity. Since equipment downtime is one of the major reasons for lost production, the Kennecott Minerals Company has developed a comprehensive maintenance information system which now assists the maintenance department in minimizing equipment downtimes. This paper discusses the primary features and functions of this system, the state-of-the-art technology that has been applied, and the benefits that resulted from using this system. Programs to support mobile equipment maintenance scheduling, which currently are under development, are reviewed and a summary of future applications is given.

Jan 1, 1982

By K. C. Vories, C. D. Elifrits, F. F. Haston

The required reclamation of land disturbed by surface coal mining often results in the creation of some oversteepened slopes that are prone to rapid erosion and sediment production. This natural activity on such slopes is not desirable nor allowed under current regulations. Experience has shown that novel approaches must be devised to address the problem. Research conducted on field sites in Missouri has indicated that construction, during the reclamation and grading processes, of a man-made drainage system will control the erosion. The drainage system must replicate or exceed the natural system in terms of drainage density and channel frequency. Basic design considerations are summarized in this paper, and field results are shown.

Jan 1, 1987

By Dirk van Zyl, Clint Strachan

A study was conducted to assess the feaeibility of increasing the heap height above one lift at the Alligator Ridge Mine. This study concentrated on the physical aspects of the heap and liner performance. Two principle aspects were addressed during this investigation: (a) the adequacy of heap permeability under present and future loading conditions; and (b) the adequacy of the liner to limit seepage losses. Field and laboratory test a were performed and their details and results are presented. It was concluded that the permeability of the heap would remain adequate for higher heap. The geometry of the heap will be the major constraint. It was also concluded that the liner would perform satisfactorily beneath higher heap.

Jan 1, 1987

By Robert A. Westin

Polychlorinated biphenyls (PCBs) are a group of chlorinated chemicals that were used in many different fire resistant hydraulic fluids, heat transfer fluids, and in electrical equipment as dielectric liquids. PCBs were manufactured primarily by Monsanto Chemical Company under the tradename Aroclor, and were used by many different electrical equipment manufacturers. PCBs are noted chiefly for their extreme chemical inertness. This resulted in exceptional fire resistance and long life in applications involving exposure to high temperatures and intense electrical fields. This combination of properties resulted in PCBs being widely used in electrical equipment used in mines, including transformers, capacitors, and some electric motors. PCBs were also used as working fluids in some heat transfer and hydraulic sys terns. The same chemical resistance that gave PCBs long life in industrial applications give PCBs essantially eternal life when they are released into the environment. PCBs are not highly toxic in the sense that exposure does not cause immediate health problems. However, PCBs accumulate in the human body and neither degrade nor are eliminated from the body, and long-term exposure to PCBs can result in changes in liver function which may increase susceptibility to the carcinogenic effects of other chemicals. PCBs also accumulate in the food chain; the concentration of PCBs in fresh water fish may be several hundred thousand times as high as in the water the fish are taken from.

Jan 1, 1981

By R. M. Hernandez

The Bureau of Land Management (BLM) constructed four passive biochemical reactor systems (BCRs) to treat mining influenced water (MIW) in the Bunker Hill Superfund area near Coeur D?Alene, Idaho between 2002 and 2003. Initially, the BCRs operated very effectively. However, in the past couple of years, the zinc removal effectiveness of the four BLM BCRs has declined [1]. The central objective of this study was to characterize the microbial communities and substrate present within the BLM BCRs and to use these factors to propose strategies to promote sustained sulfate reduction levels. Microbial communities were characterized by quantifying total bacteria and sulfate reducing species. Substrate was characterized by quantifying the percent organic, acid soluble organic, acid insoluble organic, and bioavailable material within the BCR. The results suggest the depletion of bioavailable organic substrates is the primary cause of the decline in zinc removal and not the microbial community structure. The ability to assess the amount of bioavailable organic substrate and microbial community is important to the understanding of the sulfate reducing capacity of the BLM BCRs and developing strategies to facilitate performance enhancement of the current BLM BCRs. The characterization of organic substrate and microbial community structure are also important to improving design of future passive treatment systems for mining influenced waters.

Jan 1, 2010

By O. J. R. Baena

Mining activity in the Segovia region in NE Colombia is the main source of employment in the local economy. This has created major problems of illegality and informality mining associated with a high social and environmental impact, as inefficient technologies are used and high consumption of toxic substances required in the process of gold recovery by amalgamation and cyanidation. In this work is presented mineralogical characterization of six local mills and studied beneficiation processes developed in them. With the results presented a proposed plant design that eliminates the use of mercury by replacing gravity concentration processes taking advantage of the characteristics of the treated material. Significant results were obtained regarding the recovery of precious metals and present a methodology that can be replicated in other mineral beneficiation plants that use gold amalgamation processes. This implies a significant reduction in mercury use and decreased risk of human contamination associated with this.

Feb 23, 2014

By R. Poulin, A. Lamontagne, N. Tassé

This paper presents the results of a laboratory investigation aiming to verify the concept of co-mingling of waste rock with layers of compacted tailings. Overall, co-mingling is expected to delay the onset and reduce the magnitude of acid mine drainage (AMD) production in waste rock. To denionstrate the efficiency of the method proposed, five different column tests have been set-up. Columns were fed with deionized water at the top and drainage waters were collected and analyzed. Bacteria counts were done on the tailings and waste rock after the column tests. Permeability in saturated conditions and capillary parameters were measured for the tailings. The results obtained show that the co-mingling method would be effective in mitigating AMD by maintaining nearly water-saturated conditions in compacted tailings, thus reducing oxygen supply in waste rock by preventing thermal air convection and minimizing oxygen advection and diffusion.

Jan 1, 2000

By L. Barry Phelps

The complexity of surface mining operations is increasing as attention is directed towards mining larger tracts of lower grade, higher cost deposits. Large tonnage requirements from these mines necessitate utilization of many large pieces of equipment. This equipment must be utilized efficiently, with production maintained at or near designed capacities. Basically, the problem is to select, size, and schedule equipment to maximize profits and minimize adverse environmental impacts (Anon., 1977). The time, manpower, and cost limitations required to analyze a wide variety of situations and alternatives in planning surface mines have been sidestepped with the application of simulation methods using a digital computer. Since a simulator can be programmed to represent the situations which are to be analyzed, many alternatives can be evaluated in a relatively short time. Input variables are easily changed and the resulting changes which take place in the system can be analyzed. When standard methods of analyses are applied, weeks and many man-hours are involved in analyzing large-scale mining operations. At the same time many simplifying assumptions must be made since these operations are dynamic and transient. Hence, it becomes difficult to make sound engineering decisions and take proper and timely corrective action in the absence of simulation methods. This chapter is concerned with the application of one such method, namely, the open-pit materials handling simulator (OPMHS) developed by the Mining Engineering Section, The Pennsylvania State University (Manula, Albert, and Ramani, 1977).

Jan 1, 1979

By T. I. Probert, B. W. Burdett, L. B. Hales

Selecting a mineral processing control system from the multitude of offerings can be a formidable task. To assist the plant designer, the material in this chapter includes the advantages and disadvantages of different equipment types, configurations, and control strategies. Selection procedures are detailed, and the importance of each step in the design and selection process is explained.

Jan 1, 1986

By S. Horton, F. L. Stanley, P. J. Bethell

Introduction The McClure River Processing Plant is located at McClure in Dickenson County, VA. The plant was originally constructed in 1979 as a 600 st per hour facility. The plant is fed by coals from numerous mines in the area as well as a major longwall mine onsite. Coal is processed predominantly for the metallurgical coal market. The original plant was comprised of three separate processing circuits incorporating a heavy medium vessel for the coarse material (+10 mm). Intermediate sized material (10 x 0.6 mm) was beneficiated in heavy medium cyclones, with the remaining fines (0.6 mm x 0) passing to froth flotation for upgrading. The products from all three circuits were combined prior to thermal drying and then stored in silos or ground storage prior to shipment to the metallurgical coal markets. A middlings heavy medium cyclone circuit was also present to rewash the vessel and primary heavy medium cyclone rejects. The original circuit is as shown as Fig. 1 (Editor's note: All figures are reproduced at the end of this paper.) In reasonably close proximity to the McClure Plant is the much older, less efficient Moss 1 Plant, (Chance cone, table, water only cyclone, froth flotation, Fig. 2), which prior to the McClure Plant expansion was processing considerable tonnages of coal. At that time, the McClure River Plant was processing coal at the maximum possible feed rate, and the Moss 1 Plant was finding increasing difficulty in maintaining the stringent quality specifications on its major metallurgical coal accounts. Given the fact that many of the feeder coals to Moss 1 could be moved with minimal difficulty and cost to McClure, an exercise was conducted to evaluate the potential of expanding the McClure Plant. This would result in transferring coals from Moss 1, thereby increasing yield, reducing operating costs, and enabling customer specifications to be met more easily. After evaluating many possible ways of expanding the McClure Plant, we eventually settled on an approach based on the idea of Gallagher at German Creek in Australia (Gallagher, 1986). Our objective was to increase plant capacity by removing the coarser size fractions (0.60 x 0.15 mm) from froth flotation and at the same time eliminating the finer fractions (1.25 x 0.6 mm) from the heavy medium cyclone circuit, thereby allowing these circuits and therefore the plant as a whole to increase its capacity. These size fractions (0.60 x 0.15 mm from froth flotation and 1.25 x 0.6 mm from the heavy medium cyclone circuit) would be treated in a new spiral circuit. After desired evaluation of the various circuit capacities, including desliming screen, clean coal filter and thermal dryer capacities, etc., it was concluded that we should be able to maintain high levels of processing efficiency in the existing circuitry while at the same time expanding plant feed rate from a nominal 600 st per hour to 1000 st per hour, thereby achieving the objectives The circuit that was finally settled on is shown in Fig. 2. Several unique features were incorporated in this circuit in an attempt to maximize processing efficiency and reduce maintenance costs. First, the idea of a single-stage spiral circuit was abandoned in favor of a two-stage circuit incorporating rewashing the primary spiral middlings in a secondary spiral (Bethell, 88). The spirals selected were Mineral Deposits Model LD4 units. It was felt, after much previous testing, that spiral middlings rather than being a true middling gravity fraction were in fact a combination of true middlings with a preponderance of misplaced light coal and high-density rock. Consequently the insertion of this material directly into either clean coal or refuse streams (per normal practice) would only lead to loss of efficiency. The operating philosophy behind the design of the circuit was to produce the purest coal and rejects possible by adjusting the spiral splitters. Misplacement of refuse into the clean coal and vice versa would be minimized by taking a fairly large middlings cut. By reprocessing this material (10%-15% of primary spiral feed) in a secondary bank of spirals the misplaced material in the primary middlings would be reprocessed and its probability of reporting to the correct stream greatly enhanced. To minimize fines loading on the spirals, fine aperture sieve bends were to be included. A further novel feature of the circuitry is the desliming/ dewatering system. A philosophy of accepting inefficiency but forcing it to work in our favor was developed. The dewatering screens (Linatex Combis) were chosen not for their ultimate screening efficiency but for their ability to remove slimes (tolerating a fair quantity of oversize in the effluent) and their enhanced maintenance characteristics. Any oversize passing into the effluent, together with the fine coal centrifuge effluent, would pass to classifying cyclones, the objective of which was to reject to overflow (and hence froth flotation) as many fines as possible (-150 µm) without running the risk of losing coarse (1.25 x 0.15 mm) material to oversize. Hence, by a process of producing a "slime free" screen product coupled with a "coarse free" cyclone overflow, sizing efficiency could be maximized. Obviously, recirculating load had to be factored into the Combi Screen design capacity. The spiral circuit as shown in Fig. 2 was installed at McClure River in January 1988. The spiral circuit efficiency was very high immediately, and, after the normal debugging, plant capacity has been increased to the point at which we are currently processing of the order of 1100 st per hour. Test program The performance of the spiral circuit has been evaluated by two major samplings of the entire new circuit, coupled with routine bi-monthly tests on all other major components of the plant circuitry.

Jan 1, 1992

By J. E. Taylor

A detailed planning and design project has been undertaken at Callide Coalfields, as the first step towards implementing a fully integrated mine graphics system. The system, when fully installed, will support applications ranging from business graphics through to terrain modelling and computer-aided design. The conceptual design which will accomplish this is presented. The problems of retrospectively applying graphics standards to existing applications are discussed, and a practical solution outlined.

Jan 1, 1986

By A. Shah, L. W. Saperstein, M. C. Radomsky, D. L. Passmore

The development of microcomputer software that provides an analysis of pit-specific accident and production data for the mining industry is seen as a vital component in a total loss-control system. The Mine Injury Reporting System (MIRS) allows users to access accident and production data prepared by the Health and Safety Technology Center of the Mine Safety and Health Administration of the US Department of Labor for any particular state and to generate a simple, yet informative, report.

Jan 1, 1990

By Kostas Fytas

A computer package has been developed which is capable of evaluating alternative production schedules (long and short range) of an open pit mine once the ultimate pit limits have been defined. The model user can choose the best alternative according to cash flow considerations and the particular mining conditions. The package involves a combination of simulation for long range production scheduling and linear programming for short range scheduling. The simulation model based on an iterative technique, maximizes the profits within each long scheduling period (eg. year or sixth month period), and at the same time defers stripping as long as possible. A minimum exposed ore quantity is kept at the beginning of each mining period. The final long range schedule satisfies a set of constraints for each period, mainly ore quality and quantity constraints for ore and waste. An interactive smoothing procedure at the end of each period results in a schedule that is feasible in terms of mining practice. Finally a cash flow analysis model carries out cash flow calculations so that the user can select the best alternative. The linear programming model, based on a certain number of shovel regions, defined interactively by the model user, calculates the optimum production schedule for each short period under consideration, so that a set of constraints is satisfied.

Jan 1, 1986

By R. L. Grayson, S. Yuan

A goal-programming-based, worker-scheduling model has been incorporated in the Mine Management Support System (MMSS) for assigning workers to prioritized jobs on a shift basis. In the model, the accomplishment of each regular and non-regular job is a goal, and the objective is minimization of the deviations from the goals. A number of coefficients are employed as premultipliers of the decision variables to address practical considerations associated with the utilization of workers and the requirements of jobs. This model is applied to a 41-worker problem.

Jan 1, 1992

By Jerry Peterson

Mine maintenance planning, scheduling and daily workflow communications are crucial elements for enhancing overall efficiency and reducing costs. Equally important, it helps identify time periods that equipment will be unavailable so conflicts with production demands are avoided. The current CMMS Kennecott Energy Corporation (KEC) utilizes does not perform these functions in an effective manner. A solution to this problem was to develop an intuitive web-based maintenance planning, scheduling and work flow system call E-MESA. This paper will discuss the E-MESA'S system structure and advantages and disadvantages of using the web based E-MESA solution to perform the maintenance functions described above.

Jan 1, 2002

By Richard R. Klimpel

This article introduces the basic definitions and philosophy behind process hazard evaluation procedures and the determination of risk as being a function of accident probabi1ity and accident consequence. The general concepts of good engineering practice and predictive hazard evaluation are discussed. The most commonly employed methods used in the processing industries are reviewed with an eye towards briefly presenting what each method offers as far as information, time and resources required, etc. Some initial references on the actual practical use of each technique in the processing industries are also given.

Jan 1, 1991

By Heinz Distelmeier

The New Austrian Tunneling Method was, as is well known, developed from conventional rock tunnelling. In Germany about 10 years ago the NATM began to be applied to partially stable soils by incorporated excavation and support methods to allow its use with these soils. The advantages of this tunnelling technique - adaptability, ecomomy, and quality have resulted in its widespread usage. Today, about 85 % of all mined tunnels in Germany are produced with this technology. This rapid development has resulted in about 40 companies operating within a geographical area about the same size as the state of Illinois that are capable of utilizing the NATM. In most cases German contract/award procedures allow the contractor to develop alternate design and plans. As a result of this flexibility and intense competition, safety factors have been gradually reduced to the lower limit of what could be regarded as demonstrably safe, and the utilization of the NATM has expanded to include higher risk conditions, namely * excavating larger cross sections. * working with less overburden. * work undertaken under less stable soil conditions.

Jan 1, 1983

By Helen Joyce, Larry Twidwell, Jay McCloskey, Eric Dahlgren, Andy Hadden

The reduction of dissolved selenium oxyanions from mine wastewater utilizing an elemental iron cementation technology on been studied on a laboratory scale at Montana Tech of The University of Montana and on a pilot scale at MSE-Technology Applications as a water treatment process potentially capable of removing dissolved selenium to GO WL. Laboratory and pilot scale studies using elemental iron have demonstrated effective removal of dissolved selenium. Enhanced selenium reduction rates have been demonstrated when galvanically coupled iron/copper and iron/ nickel are utilized. The laboratory and pilot scale results are presented and discussed.

Jan 1, 2005

By Talaat A. B. Lawendy, Guerry H. McClellan

Batch laboratory-scale flotation tests were conducted on some carbonate-containing sedimentary phosphate ores to obtain concentrates suitable for chemical processing. The phosphate samples tested contained both calcite and dolomite. The calcitic phosphate ore was from Israel and the dolomitic ores were from China, India, Egypt, and Pakistan. The phosphate sample from Pakistan also contained a significant amount of silica. Several flotation techniques that have been proposed for upgrading carbonate -containing phosphate ores and concentrates were tested. Two processes gave better results compared with the other processes tested: a modified IMC anionic process and a. phosphoric acid depression process. At the best flotation conditions tested, phosphate concentrates assaying 32.5%-36.5% P205, 44.0%-51.0% CaO, and 0.6%-1.0% MgO were obtained at 69%-76% overall P205 recoveries from run-of-mine (ROM) ores containing 16.0%-25.0% P205, 40.0%-52.0% CaO, and 1.0%-11.6% MgO.

Jan 1, 1993

By Robert M. Dreyer

The first time that a geologist is confronted with the necessity of evaluating a lateritic ore deposit, he may feel that nothing could be easier. Why should there be any problems in making an economic evaluation of a relatively flat-lying, surficial ore body? After several hundred thousand dollars worth of frustrating work often culminating in a series of non-reproducible data - the evaluator may be a sadder and wiser man. This paper will try to illustrate why the evaluation of lateritic bauxite and nickel deposits is among the most difficult problems confronting an economic geologist - and, more especially, how this problem can be solved. Volumes have been published on descriptive and genetic studies of lateritic ores. Obviously, there is time today only for the briefest description of such an ore body. The laterite is a soil formed under tropical conditions and resulting in the concentration, within the soil zone, of certain tri-valent metals.- especially, aluminum and nickel. The soil zone is divided into two parts: (a) the true soil or lateritic zone and (b) the zone of, partially altered bed rock or saprolite. It is important to remember that, whereas bauxite generally is confined to the laterite zone, nickel deposits occur in both the laterite and

Jan 1, 1977