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By L. B. Rothfeld

In anticipation of RCRA reauthorization and subsequent rulemakings, the Bureau of Mines is studying potential economic impacts of RCRA on mining. For U.S. copper heap and dump leaching operations in a variety of terrains, the cost of liners and closure caps to comply with RCRA Subtitle D ranges from $55 million to $158 million per site, or about $500,000 per hectare ($200,000 per acre). If RCRA technology requirements and financial assurance had been required on current operations, 27 to 100% of production from heap and dump leaching would have been non-competitive at market prices between $2,310 and $1,650 per metric ton ($1.047 and $0.75 per pound) copper. This result is based on an analysis that considers return on capital, corporate overhead, marketing, and freight costs as well as operating and maintenance costs at the mine. Over the same price range, economic analysis using the IMPLAN input-output model on one-or two-county regions indicates potential net job losses of about 570 to 2,700 jobs. Total economic output of those counties could be reduced by about $180 million to $360 million.

Jan 1, 1994

By Jr. Lownie

Estimates of the cost of producing any commodity generally fall into several classes depending upon the motives and needs of the estimator. There are estimates intended to show how low costs might be with favorable conditions if everything goes well. At the other extreme, there are estimates which show how high costs might be if troubles develop. The estimates in this paper for the cost of producing direct reduced iron (DRI) are accompanied by discussion to point out how the final figures may be adjusted in either a promotional or a conservative direction. Because we do not have a specific process and a particular set of conditions in mind when discussing this subject today, this paper deals with the general situation, with considerable attention to how the estimates can be made more specific once one knows the particulars of a given situation.

Jan 1, 1978

By P. E. Sperry, J. M. Duncan

INTRODUCTION The purpose of the report on which this paper is based is (1) to evaluate the potential for cost reduction of urban mass transit tunnels by use of alternative materials transport systems during the tunneling process, and (2) to identify research and development program elements to assure that the materials transport system will not become the limiting factor for the rate of excavation. The approach taken was: Review the state of the art of urban tunneling by extensive interviews with representatives of tunnel contractors, equipment manufacturers, government agencies and consultants, and by review of recent literature.

Jan 1, 1979

By Robert B. Scott

Acid mine drainage, discharging from coal beds, has polluted our streams and rivers since early time. These pollutants affect water quality by lowering the pH, reducing natural alkalinity, increasing total hardness, and adding undesirable amounts of iron, manganese, aluminum and sulfates, The tangible damages are the costs involved in replacing equipment corroded by the acid water, additional treatment costs at municipal and industrial water treatment plants, and damages resulting from corrosion of steel culverts, bridge piers, locks, boat hulls, steel barges, pumps, and condensers. Intangible damages, which are real and important, include destruction of biological life of the stream, reduced property values, and streams rendered undesirable for recreational uses.1 The major problems of mine drainage occur in the anthracite and bituminous coal regions in Appalachia. However, many of the western mining states have significant mine drainage problems in specific areas, but the overall problem is not as great as in the eastern states.

Jan 1, 1970

By J. A. Herbst, A. E. Oblad, Y. C. Lo

The major cost in comminution is energy consumption, which can be as high as 50% of the operating cost. Improvements in plant operations have resulted in up to a 15% reduction in energy usage (kw-hr/t). These improvements have been made through the optimization of grinding efficiency and the use of expert model-based control systems. Optimization involves the determination of the levels of the critical-operating conditions that result in the most efficient breakage of ore in the mill. These optimal levels are identified through plant/laboratory test work and through computer simulation using advanced process models. Model-based expert control achieves the maximum performance from the grinding circuit by identifying the characteristics of the ore in the mill with an optimal on-line estimator. Using this information, the control system dynamically determines the operating point that will yield the optimal performance. Two industrial applications of grinding-circuit optimization and model-based control are presented to demonstrate the power of this new technology.

Jan 1, 1997

By V. C. Lo

The major cost in comminution is energy consumption, which can be as high as 50 percent of the operating cost. Improvements in plant operations have resulted in up to a 15-percent reduction in energy usage (kwh/t). These improvements have been made through optimization of grinding efficiency and use of expert model-based control systems. Optimization involves the determination of the levels of the critical operating conditions that result in the most efficient breakage of ore in the mill. These optimal levels are identified through plant/laboratory testwork and computer simulation using advanced process models. Model-based expert control achieves the maximum performance from the grinding circuit by identifying the characteristics of the ore in the mill with an optimal on-line estimator. Using this information, the control system dynamically determines the operating point that will yield the optimal performance. Two industrial applications of grinding circuit optimization and model-based control are presented to demonstrate the power of this new technology.

Jan 1, 1995

By A. Anani

The goal of hot mix asphalt (HMA) design is optimal material blending to meet Superpave specifications. HMA cost minimization has being modeled as linear programing (LP) (Awuah-Offei et al 2011) and mixed integer LP problems (Brown et al, 2012) and solved with commercial software such as LINDO and CPLEX. Often these software, which are designed to solve general optimization problems, have licenses that cost thousands of dollars. The objective of this study is to develop a novel solution algorithm to the HMA optimization problem presented by Brown et al. (2012), which will negate the need for expensive commercial packages and is specific to this problem. This novel algorithm is based on the branch and bound algorithm for solving mixed integer problems. The algorithm is incorporated into a software package with an easy-to-use graphical user interface. The developed algorithm is validated using a real-life HMA problem. Using this solution algorithm will save companies thousands of dollars, otherwise used to purchase software licenses.

Feb 23, 2014

By Malcolm Wills

Boddington Gold Mine commenced operation in 1987 with an initial production of 3.0 Mt/y at a grade of 3.5 git. Head grade has reduced over the life of the mine and the major response to the drop in grade has been to increase mining rates and increase plant throughput. A capital expansion was carried out in 1996 increasing the throughput to 6.0 Mt/y and since that date tonnage has been increased without major capital expenditure. BGM's current mill throughput is 8.77 Mt/y ( 1999). In 1999 the combined basement plant and direct leach plant processed 8,770,055 tonnes to produce 233,507 ozs or 7.262882 tonnes of gold at an average head grade of 0.83 git. With grades of 0.83 git, and gold price at record lows, $US251.95loz in August 1999 or $A393.67loz it has been necessary to make and maintain major cost savings to remain profitable. Boddington Gold Mine has achieved this by a number of steps including a productivity study by outside consultants.

Jan 1, 2000

By Michael Drozd

The operation of an activated charcoal system has five separate unit operations. These unit operations have common points for CIP, CIL and CIS system, which vary widely in application. a. Absorption b. Desorption (Stripping) c. Acid Washing d. Reactivation e. Carbon Handling ( carbon transportation, sizing, de­watering, etc.) Cost optimization starts with the basic operating parameters (design philosophy) set down at the time of engineering design. This parameters undergo almost immediate change due to site specific ore requirements, throughput changes, operator requirements or reagent availability. Activated charcoal is sometimes viewed as simple, uncomplicated reagent that requires not optimization. To some extent, this statement is true, but under most circumstances, if the time necessary to optimize the use of activated charcoal is available, the effort is rewarded with significant savings. CPL-Carbon Link has embarked upon a program of supplying technical support with its activated charcoal. Several operation in the United States have under taken to have CPL-Carbon Link do an operational survey to determine if potential savings are possible. CPL-Carbon Link has offered to do these surveys for projects that are clients or simply would like to have CPL-Carbon Link review their operation. The information accumulated by CPL-Carbon Link is being used to attempt to fashion industry standards so that a common reference point came be establish for activated charcoal usage.

Jan 1, 2000

By C. Milne, T. M. Dyhr, T. E. Wilson

As time progresses, new concerns regarding long-term post-mining effects are identified, increasing mine closure costs. Regulators responding to public interest must take a “worst case” view and require post-closure monitoring or remediation processes. Although closure costs depend on the size and type of operation, general cost categories are defined, and median values (per acre, or per unit of production) are identified. Closure cost categories, as well as amounts, have increased with time. Except for increased efficiency in earth-moving and water management (surface or subsurface), there are no apparent offsets to a steady rise in closure costs. When the historical trend of closure costs is considered, it is probable that additional cost categories will come into being. For mine operators, the challenge will be to anticipate them and devise cost-effective remedies.

Jan 1, 2003

By T. M. Dyhr, T. E. Wilson

Although environmental management costs during mine operation depend on the size, type, climatic and geochemical conditions of operation, general cost categories are identified and mean values, as a percentage of total operating cost, are determined for coal and non-coal surface and underground mines (medium-size) with on-site beneficiation and tailings disposal facilities. Cost trends are charted from 1963 through the present.

Jan 1, 2004

By Joseph A. Dos Santos

"The subject of this writing was first published in 1998 with the emphasis on the hardware cost comparison. Other costs, such as the required land area and spatial volume, were mentioned but not emphasized, as these were not deemed as important for new projects where the space was appropriated as required. During the last decade, these other costs have proven to be more than equal in importance. These costs are emphasized here through specific accounts of actual highangle conveyor installations that demonstrate the importance and the high-angle advantage An update on the progress in sandwich belt highangleconveyor technology is also provided.Origin and progress in sandwich belt conveyorsCover belts of the 1950s. Large volume, highangle conveying by “conveyors with cover belt, dates back to the early 1950s, when such systems were employed at the bucket wheel excavator boom conveyor in German lignite mines to increase the depth of cut without increasing the boom length. Various systems were developed, patented and built. These systems were not a lasting success for various reasons, which are noted by Rasper[1]. In his 1958 “Review of Cover Belt Systems,” Rasper summarizes the characteristics which are worth pursing and those that should be abandoned. The former are akin to good conveyor engineering. The sandwich belt conveyor model. The first sandwich belt conveyor model allowed calculation of the required hugging pressure to develop the bulk material’s internal friction and preclude material slideback. A modern, accurate version of the sandwich belt conveyor model is presented in Fig. 1. This model depicts accurately a derating of the material cross-section allowing an ample belt edge distance that can tolerate normal belt misalignment without material spillage. The calculations must thus recognize that only part of the hugging pressure is imparted onto the material with the remainder transferred belt edge to belt edge affecting a material seal. Mathematical development of the sandwich belt model is covered by Dos Santos and Frizzell in their 1983 article, “Evolution of Sandwich Belt High Angle Conveyors.”"

Sep 1, 2016

By Suresh K. Bhatt

A mathematically simulated modeling technique is used in this U.S. Bureau of Mines paper to represent a hypothetical mining operation with existing mining technology and prevalent mining costs. Mining scenarios are prepared and evaluated for potential benefits and costs available through computer-assisted mining. Base criteria, parameters, and methodology are described.

Jan 1, 1991

By Goutam H. Shahani

The current economic downturn has been at the center of media attention for several years. Today, the mining and mineral sectors are being impacted by highly fluctuating supply-and-demand conditions, extreme price volatility and tremendous market uncertainty on a world-wide basis. There have been numerous plant closings, project cancellations and employee layoffs. In this gloomy economic environment, it is easy to forget that the world?s gross domestic product (GDP) has more than doubled in real terms during the last 30 years. While current market turbulence may continue for some time, the long-term trend is unmistakably upward. Living standards are rising all over the world, thereby creating demand for food, clothing, transportation and housing. This translates into tremendous demand for the mining and mineral sectors. In the future, new capacity and plant expansions will be necessary to meet this need. These investments, which typically have a life span of 30-plus years, will have to be based on long-term economic considerations rather than current market conditions.

Jan 1, 2011

By Bill Morgan

This paper discusses the economic zones of application for several different types of earthmoving equipment: dozers, wheel loaders in load-and-carry applications, wheel tractor scrapers, articulated trucks, rigid-frame trucks and wagons. Only the medium to large pieces of equipment were considered. From this chart (Figure 1), you can see the size range, in tons of carrying capacity, of Caterpillar equipment and the specific models analyzed.

Jan 1, 1994

By J. Wiebmer

The two most important influencers of cost-per-ton in an underground mining machine are its productivity (tons/hour) and its availability-utilization (hours/year). Operating cost and initial price have far less impact. This paper reviews a cost-per-ton sensitivity analysis for underground mining equipment and discusses benchmarks for measuring its performance. The conclusion is that miner-supplier partnerships and the Information Age are the two most significant trends in cost-per-ton reduction.

Jan 1, 1997

By J. H. Kempton

Refinement of environmental procedures can produce significant cost savings at most mines. Grouting permeable aquifers reduces water pumping and disposal costs. Stable groundwater quality supports reduced groundwater monitoring; and for contaminated groundwater, in-situ or natural restoration should be evaluated. Waste-rock characterization can be minimized using fewer (but more representative) samples, inexpensive surrogate analyses (e.g., NAG instead of humidity cells), and appropriate tests (e.g., avoid meteoric tests on sulfide). Selective waste-rock handling should be compared to random emplacement, which is often cheaper and more stable. Finally, incorporating schedule uncertainty in modeling allows the flexibility to revise mine plans within permits.

Jan 1, 2000

By Richard Keith Corbin

INTRODUCTION With the world media full of predictions that the price of gold will quadruple in three years (Maybury, R.J., 1988), and with financial forecasters and strategists touting opportunities to make 400% in gold (Skousen, M., 1988), explorationists and entrepreneurs are scurrying to find enough gold to feed the global gold fever created. At the same time, gold deposits in the United States and other developed and intermediate countries are becoming less attractive because of environmental restrictions, radical reductions in tax incentives, and depleting reserves, causing people in the mining industry to begin looking at opportunities for foreign investment in gold mining concessions in lesser developed countries (LDCs). Meanwhile, LDCs are responding with chamber-of-commerce aplomb in marketing their opportunities. In the face of all this frenzy and hype, targeting gold mining concessions in LDCs for foreign investment may be done more objectively by employing a systematic approach. For this paper the SHOP rating system (Corbin, R.K., 1987), which considers factors of the LDC's stability, hospitability, ore occurrence, and profitability potential is used. The result is that a tiny banana-growing republic in Central America, first discovered by Columbus and named the "Rich Coast'' because of the many gold adornments worn by its Indians, has been rediscovered and emerges as a classic LDC gold target.

Jan 1, 1988

By Steven M. Bishoff

The reclamation of surface land areas disturbed during the course of coal recovery became a major, universal consideration upon the implementation of the Surface Mining Control and Reclamation Act of 1977. This legislation not only established reclamation as an absolute requirement, but also presented guidelines for reclamation standards and required bond-posting procedures to assure completion of the reclamation process. The Office of Surface Mining was established to enforce the provisions of the Congressional mandate by promulgating specifically detailed regulations and supervising the State participation in this regulatory process. The major operational consequences of the reclamation-related provisions of the Act and the OSM regulations are the increased costs and complex procedures necessary to accommodate the regulatory authorities. It is anticipated that many of these costs and procedures have not been adequately evaluated by either the coal operators or the regulatory bodies. It is, therefore, necessary to proceed with an examination of the general reclamation processes, the effect of these processes on product costs, and the methods, if any, which may be utilized to minimize their impact on the overall operation.

Jan 1, 1981

By Michael J. Howes

The nature of business in a free enterprise system is to maximise the return on an investment i.e. to maximise the wealth of the shareholders. This is normally achieved within constraints dictated by many agencies, one of which is the health and welfare of the employees. In the mining industry considerable effort has been expended in improvements in this field, however, the major problem still confronting the practicing ventilation or environmental engineer is the determination of what standards he should design for, which satisfy both the economic and health requirement s. Normally the basic health requirements are satisfied by the minimum standards defined in regulations and codes of practice. These are, however, based on an acceptance of a certain risk or lower production potential. A prime function of the ventilation engineer is therefore to financially justify and implement improvements to both standards and systems. The main purpose of this paper is to examine the basis and techniques of providing this financial justification. Changes in existing methods to achieve the same standards but at lower costs are also covered.

Jan 1, 1980