Search Documents

By I. R. Firth, D. L. Taylor

The ability to accurately model the movement of grade boundaries during a typical bench blast would be of significant benefit to mine operators. The movement of grade boundaries during the blasting process may have significant impact on grade recovery if not accounted for. The paper describes the preliminary stages of a research project which combines numerical blast models and conventional mine planning software to allow practical use of the results of a numerical blast simulation. A two dimensional bench blast is simulated using the Universal Distinct Element Code (UDEC). The results of the simulation are used to provide input to the Surpac mine planning package which can be used to generate grade control plans.

Jan 1, 2001

By J. P. Gliddon

Since 1980 a number of significant changes have been introduced at Palabora in an effort to off-set the effects of reduced product price and increased unit cost of inputs. These changes and improvements include major equipment rationalization programs, the introduction of trolley assisted truck haulage, adoption of a sophisticated computerized truck control system, pit design enhancements, improved drilling practices, use of emulsion explosives and the installation of an in-pit crushing and conveying system. The various changes, their effect on the operation and their contribution to cost reduction and improved productivity at Palabora are considered.

Jan 1, 1987

By J. P. Gliddon, G. C. Wade, J. W. Lill

Since 1980 a number of significant changes have been introduced at Palabora in an effort to offset the effects of reduced product price and increased unit costs of production. These changes and improvements include major equipment rationalization programs, the introduction of trolley-assisted truck haulage, adoption of a sophisticated computerized truck control system, pit design enhancements, improved drilling practices, use of emulsion explosives, and the installation of an in-pit crushing and conveying system. The various changes, their effect on the operation, and their contribution to cost reduction and improved productivity at Paihbora are considered.

Jan 1, 1987

By H. Reed

The precious metal mining industry in Nevada handles and generates a certain amount of hazardous materials and waste on a regular basis. These products range from processing material additives to wastes from laboratory testing, heap leaching, and hydrocarbon treatment and disposal. The volume of materials and wastes is dependent upon the amount of ore processed. Handling, treatment and disposal is dependent on the type of material handled and the waste generated. Owing to the health and safety concerns and due to the existing regulations that control handling and disposal of hazardous materials and wastes, the mining industry is obligated to comply with all applicable requirements for proper handling of these products. Plus, in an effort to minimize any impacts from this effort, the industry is continually looking for alternative methods to accomplish these requirements and to also minimize costs. This paper will discuss the general, and in some cases the specific conditions, by which the industry is coping with the issue and efforts to minimize any impacts from handling, treatment and disposal for hazardous materials and wastes. The subject of compliance with the Toxic Release Inventory (TRI) requirements and bio-treatment of wastes and other technologies will be discussed.

Jan 1, 2001

By J. R. Koehler

Mining practices at the Sunnyside Mines, Sunnyside Coal Company, Sunnyside, UT, have been documented by U.S. Bureau of Mines researchers to preserve the extensive history of yield pillar-based longwall gateroad system evolution on the property. An overview of the historical mining conditions, practices, and innovations that resulted in the evolution of the two-entry yield pillar gateroad system currently employed at Sunnyside was developed from interviews of 30 long-time Sunnyside employees. Employing yielding chain pillars at Sunnyside virtually eliminates tailgate pillar bumps and contributes to reducing face bumps. Limiting the overall width of the gateroad system benefits bump control and especially, roof and floor stability.

Jan 1, 1994

By G. A. Campbell

This paper considers the international market trends of the rare earths and how they are strongly influenced by the by-product/co-product nature of their mining and processing. The two main economic minerals for the rare earths are bastnasite and monazite. Monazite is primarily a by-product of mining ilmenite and rutile and is affected by changes in these markets as well as the presence of thorium. Bastnasite is a by-product of mining iron ore in China and a stand-alone product in the USA. The paper will use conceptional relationships and empirical data to delineate the various by-products/co-products relationships and how they determine observed international market behavior.

Jan 1, 1996

By M. S. Enders

The McDonald deposit is a volcanic-hosted epithermal gold resource that is estimated to contain 251,000 kg of gold in 375 Mt of ore at an average grade of 0.7 g/t gold. Phelps Dodge exploration geologists, working for the Seven-Up Pete Joint Venture, discovered the deposit in 1989. By the end of 1992, 494 drill holes for over 113,000 m of drilling, bulk sampling, soil geochemistry, geophysics, metallurgical testing, engineering, and environmental studies had been completed to support feasibility studies. The discovery of McDonald required vision, persistence, and commitment of everyone from the geologist on the drill rig to the senior management of the company.

Jan 1, 1995

By Stephen D. Schwochow

Aggregate producers nationwide well recognize the numerous problems often faced in securing local approval to open and operate new gravel pits and rock quarries. Similar problems are faced in Colorado, but this region also presents certain political, social, and geological complexities that have become particularly troublesome in the last 10 years. The gravity of the local permitting dilemma can be related directly to the worsening supply-demand imbalance for aggregates in the state's most populated area, the Front Range urban corridor, particularly the Denver metropolitan area. The drive to develop crushed-rock reserves to supplement dwindling alluvial supplies and to meet increasing regional growth demands was somewhat predictable but perhaps more a "last resort" alternative forced onto producers by a hesitant and often apathetic government.

Jan 1, 1982

By B. K. Cantrell

The use of diesel equipment in underground coal mines is controversial because "whole diesel exhaust" is regarded as "a potential occupational carcinogen" by the National Institute for Occupational Safety and Health (NIOSH). Threshold limit values (TLVs) are recommended for the gaseous pollutants; CO, CO2, NO, NO2, SO2' and some hydrocarbons emitted in diesel exhaust. There is, however, no TLV recommended for diesel exhaust aerosols (DEA) nor is there a standard method for sampling these aerosols. The University of Minnesota and the Bureau of Mines have collaborated to develop a personal diesel exhaust aerosol sampler (PDEAS) which utilizes size selective, inertial impaction and gravimetric analysis. During the field tests of this sampler, numerous air quality measurements were conducted in underground coal mines using diesel equipment. The objective of this report is to present these data and to assess the impact of diesel face haulage equipment on mine air quality.

Jan 1, 1991

By J. R. Sims

Gold assays from production blastholes in the Mercur Hill Pit were used to delineate known ore zones and to determine how well previous exploration drilling defined these zones. The most important factors causing inadequate ore zone definition were: 1) inappropriate location of drill holes relative to the ore zones, 2) presence of stopes from previous mining, 3) sampling and assaying errors, and 4) smoothing of the ore zone boundaries during ore reserve estimation. Infill drilling strategies were evaluated to determine the efficiency with which a given drill pattern defined the known ore zones. A drilling strategy was developed which improved ore zone delineation when compared to techniques which maintained uniform drill spacing.

Jan 1, 1992

By Bern Klein, Rafael Fernandes de Mesquita, Fatima Regina Ney Matos, Andre Xavier

"193 United Nations members are signatories of the 17 Sustainable Development Goals (SDGs). Even though it does not make it legally binding to the country members, the SDGs establishment incites national and managerial frameworks to achieve the SDGs. The mining industry inserts itself in this context by its global presence and frequent location within ecologically sensitive and less developed areas. This paper aims to consolidate the state of academic research on mining, sustainability and sustainable development, by organizing the results of previous studies within a systematic review on the SDGs set. To do so, the ISI Web of ScienceTM Core Collection database was chosen as a database of record, as it is one of the most widespread databases of academic journals. We have used all years available in the ISI database, from 1945 to 2016 (for complete years). The systematic review process comprised of five steps: (i) to search terms [(“sustainability” or “sustainable development”) and mining] on the database and to apply filters of criteria; (ii) organizing papers; (iii) metrics and relations between papers and authors; (iv) classification of the results through content analysis techniques; and (v) synthesis. The results were divided in two groups: the highly cited and the most recent papers, to include papers that have academic impact and those which show the newest contributions to the field. The results showed that, in spite of a growing amount of publications in the past years that relates to mining and sustainability, the main focus of these publications are still on the environmental dimensions of the UN goals. This suggests that more practical and academic work in the mining sector are required to fill in the blank spaces regarding the other set of goals that compose the SDGs framework.Introduction A total of 193 United Nations members are signatories of the 17 Sustainable Development Goals (SDGs). Even though it does not make it legally binding to the country members, the SDGs establishment incites national and managerial frameworks to achieve the SDGs. The mining industry inserts itself in this context by its global presence and frequent location within ecologically sensitive and less developed areas (Atlas 2016). The goals are important because they add common targets for different countries and easily establish discernible criteria for it (Costanza et al 2016). A forward-looking approach like the SDGs would be able to attach the sustainable development framework with profitable activities taken by the mining companies (Starke 2016). This paper aims to consolidate the state of academic research on mining, sustainability and sustainable development, by organizing the results of high impact previous studies and recent publications, within a systematic review, on the SDGs set. By doing so, the results can portray the actual concern and the lacks that the academic field had on this subject in comparison to the UN contemporary agenda."

Jan 1, 2017

By Jim Oehler

The US minerals industry, as well we know, has been hit hard by the recent recession and is faced with what is projected to be a slow recovery. Even so, there was an underlying feeling of optimism at American Mining Congress' International Mining Show in Las Vegas, NV, Oct 11-14. More than 25,000 people attended during a particularly rough financial year, dispelling fears that attendance would dip sharply below 1978's 30,000 plus tally. The equipment expositionheld every four years-was the largest show of its kind this year in the Western Hemisphere in terms of exhibit space, providing an extensive view of mining-related equipment. In addition to the nearly 700 exhibits occupying more than 445 hm2 (11 acres), 20 technical sessions were held covering topics ranging from minerals availability and the state of the mining industries to communications, computers, and accounting. Government officials were well represented, with six US senators and five US representatives participating in various convention functions. Sen. Paul Laxalt (R-NV) was the keynote speaker at the welcoming luncheon. Other senators involved in the show included Howard W. Cannon (D-NV), Pete V. Domenici (R-NM), James A. McClure (R-ID), Frank H. Murkowski (R-AK), and Steven D. Symms (R-ID). Representatives on the program were Joseph M. Gaydos (D-PA), Guy Vander Jagt (R-MI), Don Young (R-AK), Jim Santini (D-NV), and Ceil Heftel (D-HI). There were also many international vistors at the show, including exhibitors from Australia, Austria, Canada, England, Finland, Sweden, South Africa, and West Germany. Equipment Highlights Equipment and services featured at the exposition ranged from aerial mapping to wire rope. Aisle space alone between exhibits exceeded 8 km (5 miles). And the companies represented ranged from small businesses to large corporations. Some of the company products described here are representative of the many exhibitors in attendance. Atlas Copco's extensive display of rock drilling and tunnel and shaft boring equipment featured its Boomer H-201, the newest addition to its line of underground drifting rigs; the ROC 306, a new track-mounted, high pressure down-the-hole drill rig; a new hydraulic surface crawler drill, the ROC 712H, designed for small and medium-size holes in quarries and small open-pit mines; a computerized analysis system, CARE (see page 1570), designed to project productivity and operating costs for various mining operations; several electro-hydraulic loaders, including the new rail bound LM E60 and LM E80, and two Hagg-loaders-the 7HR and 10HR-that use two digging arms to rake and guide muck; a mechanized blasthole charging system; rock bolting equipment and its new Swellex roof bolting method; Sandvik Coromant drill steel and bits; and its new Jarva R200 raise boring machine.

Jan 11, 1982

By W. Choi

The present study revealed that the bioleachability of a chalcopyrite flotation concentrate is influenced by the semiconductor properties of CuFeS2. The overall reaction of biooxidation,

Jan 1, 1991

By J. P. McKinney

A mathematical model is presented for the electrokinetic dewatering of suspensions of phosphatic clays. The modeling approach couples a boundary-element model for solution of Laplace?s equation to a recently developed constitutive equation that relates the change in solids content with applied electric field and time. The observation that the electric field controls both the maximum solids content achievable and the time required to reach that value is shown to severely constrain the application of electrokinetic dewatering strategies to an entire clay settling area. The approach, however, may be feasible for implementation as part of a continuous plant process.

Jan 1, 2011

By C. K. C. K. Gupta

The rare earths in elemental form are required for a variety of scientific and technological purposes. They are not easily obtained in this form, due to the great chemical stability of the rare-earth compounds and the strong tendency of elemental metals to react with everything they come in to contact with, especially at high temperatures. Beginning in the 1950s, when sufficient quantities of separated rare earths became available, as the result of intense research and development, three processing routes were developed to accomplish the preparation of all 16 naturally occurring rare-earth elements. They are chemical reduction of the halide intermediates, the oxides and electrochemical reduction of chlorides and oxide-fluoride mixtures. Not all the processes are effective with all the rare earths. In spite of the celebrated similarity of trivalent rare earths, the physical properties of individual rare-earth elements are sufficiently different that a variety of techniques are required for their preparation. The development of reduction processes for the rare-earth metals are covered in this paper, with focus on the oxide reduction routes. The strong reliance of effective reduction processes on the fundamental science of reduction reactions is highlighted.

By M. Javier

"Mining makes civilization possible. It also creates socio-environmental liabilities forcing us to ask how much more of this mining can our planet support. It is clear that the future of mining differs from mining in the future. The laws of nature are being compromised by mining. This paper studies the problems at the core of the mining business which need to be addressed. What kind of mining will serve our existence with nature on this planet? What kind of mining perspectives are we able to formulate without having negative effects for future generations? Is mining technologically sustainable? The values of predictions, imagination, and creativity must be integrated to define what mining should be. Those values should be in the technologies necessary to restoring equilibrium of nature (Geomimic) as well as in complete extraction of metals, better utilization of the mineral reserves, and design the usage of metals to recycle. The purpose of this research is to examine many views and perspectives for future generations and to accelerate the pace of innovation of having mining without socio-environmental liabilities by design and by understanding nature. KEYWORDS: Geomimic, Sustainability, Waste mine Design, Management by Loss. INTRODUCTION The future of mining is being stifled by many antiquated and stagnant attitudes and policies by the industry and society as a whole. The time is now or never for real action and education against these attitudes and to upgrade them to meet the current needs of this planet if we are to survive. Doing this will prove that we understand and respect nature for us and our posterity. It will also show a positive assessment that the mining process can be reversed before the point of no return. And that is to say, only if reversibility is still an option. It may not be anymore but it’s worth a try. We need to use our imagination and engineering know-how to come up with new proposals to change the core of mining. It would entail re-engineering. There is a profound difference between the future of mining and mining in the future. The future of mining is the continuation and persistence of past practices in the industry and expecting new results. Mining in the future requires a paradigm shift for extraction through modern thinking about mining as it pertains nature. The new paradigm for mining in the future would restore equilibrium with nature. Always keep in mind the connection of mining to nature. What is the future of nature? To predict mining in the future we need to use past experiences in mining and our knowledge of modern science and engineering to formulate a prototype that will enhance mining while maintaining equilibrium with nature. Mining and protecting nature are not mutually exclusive. This new prototype has nothing to do with the level of bonding or insurance that the mining industry can legally provide. The goal of this paper is to contribute some new ideas to help transform the mining industry based on the laws of nature and its limitations. Using this new prototype we will develop the following 1. Extraction of minerals Reserves-Dimensions-Technologies 2. Usage of mineral resources-Manufacture’s products designed to be reused and recycled 3. Nature- Equilibrium (physical, chemical and biological)"

Jan 1, 2016

By Clark Harrison

It is not uncommon for overall quality of coal from a mine to deteriorate as the mine is developed or for an improved-quality coal specification to be imposed during the life of the mine. Either of these conditions typically results in management pressuring mine personnel to take greater care in delineating the seam from top and bottom rock. When mining and seam conditions require a portion of the seam to be removed to ensure sufficient rock is removed to meet the quality specification, physical-coal cleaning may become economically competitive with in-pit seam grooming. The additional cost of coal cleaning may, in some cases, be justified by permitting higher recovery of the coal seam than is possible when cleaning the seam with excavators in the pit. This paper compares projected coal cleaning results with present in-pit grooming techniques and reports the economic results.

Jan 1, 1987

By Richard E. Hucko

The Coal Preparation Division of the Pittsburgh Mining Technology Center conducted an investigation to assess and compare the pyritic sulfur reduction potential of coal-pyrite flotation and high-gradient magnetic separation (HGMS). Tests were run on three coals--an Upper Freeport bed coal, a Lower Kittanning bed coal, and a Pittsburgh bed coal--to establish grade- recovery relationships characteristic of both processes. Representative portions of each coal sample were crushed to two top sizes--nominal minus 35 mesh (0.5 mm) and nominal minus 100 mesh (0.149 mm)--and subjected to conventional froth flotation. The froth product was then beneficiated by coal-pyrite flotation or HCMS to provide a direct technical comparison of the two processes. At minus 35 mesh (0.5 mm), the size normally employed for coal flotation, both coal-pyrite flotation and HGMS effectively separated pyrite from coal, and the performance of the two processes was essentially the same. At a size of minus 100 mesh (0.149 mm) , however, the performance of HGMS exceeded that of coal- pyrite flotation. The separations effected by HGMS were more efficient at minus 100 mesh (0.149 mm) than at minus 35 mesh (0.5 mm). On the other hand, it was concluded that either the effectiveness of coal-pyrite flotation decreases with diminishing top size, or the process has not been optimized to treat material finer than 35 mesh (0.5 mm).

Jan 1, 1981

By R. C. Kellner

Duval Sierrita Corporation, a wholly-owned subsidiary of Duval Corporation, operates an 86,000 STPD copper-molybdenum concentrator near Tucson, Arizona. Shortly after production commenced in February, 1970, it became apparent that the reduction crushing system represented a limitation to reaching the design capacity of 72,000 STPD. The development work performed on the reduction crushers in order to first meet design capacity, and to subsequently increase production to 86,000 STPD is described in this paper. The Sierrita plant is a conventional three stage crushing sys- tem. All crushers were supplied by the Allis-Chalmers Corporation and consist of two 58 x 89 Superior gyratories, four 138b EHD hydrocones, and ten 384 hydrocones. Screening is performed prior to and subsequent to secondary crushing and in closed circuit with the tertiary crushers. Typical throughput rates and equipment sizes are presented in Figure No. 1.

Jan 1, 1975

By Stephen H. Stow

Economically important heavy minerals have been studied in the sediments of offshore Alabama and Mississippi. Sandy samples have been collected from a 200 square mile area from Dauphin to Horn Islands. The minerals concentrate in sediments under 10-35 feet of water and may reach 2.4% by weight. The distribution of total heavies is related to the hydrodynamics of offshore Alabama-Mississippi; the greatest concentrations are in the Gulf where the longshore current is diverted from its westerly flow. Preliminary observations indicate that the distribution of individual minerals can be correlated with wave energy, particle size, specific gravity, and morphology of the mineral grains. The coarser, lighter minerals--kyanite, sillimanite and staurolite--are concentrated in relatively low energy areas in the Mississippi Sound and at the end of Dauphin Island in the Gulf; maximum concentration for each is 34.5%, 6.0% and 43.2%, respectively, of the heavy minerals. The smaller, more denseminerals--ilmenite, rutile, leucoxene, zircon and monazite--are concentrated in high energy areas in the Gulf; maximum concentration for each, respectively, is 42.0%, 5.9%, 9.652, 10.7% and 1.3% of the heavy minerals. On the basis of a minimum concentration of 1% heavy minerals, two areas have been identified and the total amounts of different minerals have been calculated to a depth of 25 feet of sediment. The data are preliminary and in no way indicate recoverable reserves, but they do show that on the order of 20 million tons of heavies exist. These deposits should be termed "indicated resources".

Jan 1, 1975