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By H. Sevim

This paper summarizes the research effort in simulating the operation of "Underground Coarse-Coal Hydrotransport Systems" (UCCHS). The equipment of the system to be simulated is already optimally selected by using an analytical optimization model. The purpose of the simulation model is to test the performance of the system and to obtain the distributions of operating parameters such as water and power consumption and amount of slurry delivered to the preparation plant. Knowledge of the distributions of these parameters is essential for the efficient operation of the system.

Jan 1, 1987

Reclamation of surface mines is a crucial environmental issue and a key challenge to the worldwide mining industry. One of the goals of reclamation is to ensure that the area is left in a condition permitting safe future use. Hence, the reconstruction of open pits, waste piles and tailings dams must satisfy appropriate geotechnical stability and safety conditions for the planned use. Landscaping in the final stages is highly relevant as the topography around the mining areas is sometimes dramatically modified by ore extraction. The reclamation strategies must be applied not only after ore exhaustion, but also during its extraction. This is a sound business strategy that leads to considerable environmental benefits and increased security of the mining operations.

Jan 1, 2003

By J. E. Gebhardt, D. A. Rice, P. E. Richardson

An improved understanding of the significant role of electrochemical reactions in sulfide flotation has evolved in the past 20 years, This understanding has been accompanied by a corresponding increase in attempts to control the electrochemical potential of flotation pulps for monitoring and controlling sulfide flotation circuits to improve metallurgical performance. This paper discusses the basic electrochemistry of sulfide flotation and the use of electrochemical potential as a control parameter.

Jan 1, 1993

By H. Kandemir, G. Neeling, P. A. Spencer

Gold extractions from three refractory sulphide concentrates have been increased by bacterial oxidation with T. ferrooxidans prior to cyanide leaching. Arsenopyrite, pyrite and stibnite were the major sulphide components associated with gold in the concentrates examined. Kinetic oxidation tests were conducted for each concentrate by monitoring iron and arsenic levels in leach slurry. A correlation has been established between the level of bacterial oxidation and gold extraction from cyanide leaching of oxidised residues. High levels of bacterial oxidation have been achieved in approximately 8 days at pulp densities of 20-25/ w/v solids, resulting in 70-90% gold extraction.

Jan 1, 1987

By M. E. Kuchta

Research is currently being conducted at the Colorado School of Mines in the use of high-pressure water for scaling down loose rocks in underground mine openings. In addition to improved miner safety, the adhesion strength of shotcrete applied to rock surfaces treated with high-pressure water is also increased significantly, resulting in improved overall support capabilities of the shotcrete layer. Test results show an increase in adhesion strength by a factor of four on a concrete test wall cleaned with water at 21 MPa (3,000 psi) as compared to a surface cleaned at 0.7 MPa (100 psi).

Jan 1, 2003

By Jennifer B. Leinart, Otto L. Schumacher

JIM ARNOLD: Our next speaker is Otto Schumacher. He's president of Western Mining Engineering in Spokane, Washington. His company offers services in the area of mining feasibility analysis and publishes Mining Cost Service. Otto's talk will be "Are Metallurgists Overpaid?" [laughter] I know one that's not. [laughter] OTTO SCHUMACHER: I really think it's kind of a dirty trick for Doug to put me up here and pose that question since I'm a mining engineer. However, it's probably most appropriate that a mining engineer address the question because I can be more objective than the rest of you. [laughter] SPEAKER. Otto, do you promise to say something nice about metallurgists? [laughter] OTTO SCHUMACHER: I'll see how much time I have. [laughter]

Jan 1, 1998

By William F. Kane, Eric C. Drumm

Rock slope failures in the Great Smoky Mountains of Tennessee are a continuing problem. A study of the geotechnical factors affecting such slopes was conducted in this geologically complex region. Seven rock slopes, five of which had undergone failure, were identified and mapped. Other parameters were mapped in addition to the standard geologic and geometric parameters. These were joint frequencies across and down the slope, and surface hardness from Schmidt hammer tests. Regression analysis on the various data revealed that Schmidt hammer hardness correlates very well with joint cohesion back-calculated from failure geometries. This approach suggests an alternative means for estimating joint strength.

Jan 1, 1986

By Jorgen Elbrond

The economic environment of mining is particular and requires special methods for seeking the economic optimization of mining and guiding the construction of logical production planning systems. An interactive program system which generates sequences of mining rates and cutoff grades, using as it's core an open-ended dynamic programming algorithm, is described. The program system is built not with the aim of obtaining a single mathematical optimum, but on the concept of satisfying the mine planner by producing several alternative mine plans and testing various schedules under conditions of uncertainty.

Jan 1, 1982

By Carol Cox Russell

More than two thousand abandoned mines within the Animas watershed in Southwestern Colorado are being prioritized for remediation by the Animas River Stakeholders Group (ARSG). Phased collection and assessment of information progressed from large scale to site specific. Prioritization was based on existing or potential environmental impact and technical feasibility of remediation as measured by dissolved Cd, Cu, and/or Zn in the discharge; indicators of habitat degradation; aquatic life in streams; cumulative impacts at the point of compliance; cost effectiveness; treatiblity/feasibility; and cultural and historic preservation.

Jan 1, 2000

By Wm. Randolph Reed, John A. Organiscak

Haul trucks have the potential to generate large amounts of respirable dust. This respirable dust has been shown to be a health hazard to personnel, especially if it contains a high silica content. Lack of dust sampling data from haul trucks prompted the completion of a study to quantify respirable dust concentrations. These field studies were conducted measuring instantaneous respirable dust at stationary locations from passing haul trucks at a stone quarry and a coal mine site. Fugitive dust levels from haul trucks were analyzed to characterize dust dispersion. This analysis will indicate safe following distances for haul trucks and other heavy equipment to avoid over-exposure of respirable dust from the lead haul truck.

Jan 1, 2005

By E. Sarris

Tailings dams are large-scale earth-fill embankments that are designed to contain mining wastes from ore dressing plants. Most commonly tailings dams are constructed in stages in order to keep up with the increasing volume of mine tailings. Staged construction using various methods (like up-stream, down-stream, and centerline) is generally considered as a very effective way to construct this kind of embankments. The present study is devoted to the investigation of the behavior and the stability of these geostructures under static conditions. In order to accomplish this task, elaborate two-dimensional numerical models are examined, utilizing the geotechnical finite-element code PLAXIS. Numerical analyses are conducted for all three types of tailings dams in order to obtain the potential modes of failure, while the corresponding factors of safety are determined by the shear strength reduction technique.

Jan 1, 2005

By Thomas E. Shufflebarger

Glass sand is a virtually pure, fine- to medium-grained, quartz sand. It is produced in 25 states from a variety of chemically different source rocks. Deriving their raw material largely from either friable sandstones or loosely consolidated sands, 59 operations produced 14.9 million tons of melting sand in 1976. About one-third of this tonnage was obtained from the Oriskany and St. Peter Sandstones. Glass-sand prospects are discussed in this paper with regard to chemistry, environment, transportation, and costs. Demand for a quality product will range from 36 million to 46 million short tons in 1995.

Jan 1, 1978

By N. R. Paterson, D. A. MacFadyen

A late-1980 airborne EM/magnetic method test over the State Line kimberlite area of Colorado-Wyoming shows weak but recognizable anomalous responses to the known pipes. The magnetic survey indicates the presence of several shallow subsurface bodies adjacent to the known kimberlites, which are interpreted as possible blind diatremes. The survey data, in profile and contoured map form, has been correlated with geological map information available at the time. It can serve as the basis for reexamining kimberlite distribution in the area, taking into account geological findings during the recent work on known bodies.

Jan 1, 1987

By R. J. Gochin, M. A. Diaz, M. L. Court

Single impact breakage tests have been carried out on samples of alumina in carefully controlled atmospheres consisting solely of nitrogen gas and water vapour. The results indicate a statistically significant increase in the surface area of the progeny particles as relative humidity rose to 50%. The majority of this increase was found to occur under conditions when adsorption was a monolayer or less. The results are consistent with the theory of surfactant-induced strength reduction of materials proposed by Rehbinder and Westwood. There are important implications where single impact tests are used as part of a design methodology for comminution machines. In most procedures relative humidity has not been a controlled variable.

Jan 1, 1995

By John B. Comer

Compelling evidence indicates that at least the plateau bauxite of northern and central Jamaica formed from volcanic ash. The predominance in plateau bauxite of zircon grains younger than the host limestones and the relative abundance of zircon grains having idiomorphic form support a direct ash-fall origin for much of the bauxite parent material. Based on revised mass balance calculations, not enough of the middle Eocene to lower Miocene host limestones have been dissolved to make an important contribution to bauxite. Likewise, the pre-middle Eocene rocks of Jamaica have made only a very small contribution to plateau bauxite; they may have made a more significant contribution to the graben bauxite of southern Jamaica.

Jan 1, 1984

By D. J. Cook, R. H. Fan, D. R. Maneval, Y-H. Shen

In this study, two placer mine processing plant effluent waters of significantly different characteristics were tested to determine the applicability of polymers along with other techniques to achieve reduced levels of turbidity. The waters from a Gilmore Creek mine and a Crooked Creek mine were characterized both as to their chemical and physical properties. The inorganic minerals were in large measure identified, and the principal cations were identified. The fine solids were studied as m their mineral identification and the extent of their electrical charges. Test work was done using polyrthylene oxide (PEO) and a liquid cationic polymer along with adjunct additives to determine optimum amounts of these coagulants for minimum consumption and optimum settling efficiency.

Jan 1, 1990

By G. Vijaya Kumar, B. Srinivasa Rao, G. V. Krishna Rao

The paper outlines the ventilation practices prevailing in coal mines of Singareni Collieries Company (South India). The high annual average surface temperature and relatively steep geothermic gradient results in virgin strata temperatures in the region of 38- 42°C creating environmental problems in the working places. Expensive methods of air cooling can not be employed as the mines are small, and production and productivity do not justify the costs of artificial cooling of mine air. Controlled recirculation of mine air -- the unconventional technique being tried with success in some coal mines in U.K. has been analysed for improving the environmental conditions. The analysis shows that the method is safe, cost effective and can be applied with very little extra equipment.

Jan 1, 1991

By Donald L. Bott

A computer model called the Quality Compliance Model was developed to optimize the mine planning and sequencing in area coal mining with respect to the limit on pounds of sulfur dioxide per million BTU imposed by regulations. The objective of the model is to maximize the amount of high sulfur coal mined from various benches while meeting the specified compl'ance standards. Given multiple seams and multiple benching operations, the mining sequence from each pit is simulated. The rate of mining is controlled such that the in-pit blending will maximize the usage of high sulfur coal and meet compliance standards. The compliant coal can be stockpiled for usage at a later date, or it can be disassociated. This calculation can be based on any given rate of production, i.e., from as small a unit as a unit train to as large as monthly or yearly production.

Jan 1, 1982

By P. C. Thakur

The history of coal mining in the United States of America and the rest of the world is replete with mine explosions and consequent loss of lives. Serious efforts in the USA to recover methane prior to mining and post mining started about forty years ago. CONSOL Energy Inc. and government agencies, e.g., the erstwhile US Bureau of Mines developed several techniques of methane drainage, such as in-mine horizontal drilling, vertical gob wells, hydrofracing of vertical wells and horizontal drilling from surface. With the current technology, thirty to sixty percent of total methane emissions from a mine can be captured making the mines much safer and more productive. Drained methane is often marketed to defray the cost of methane drainage. This paper is an anthology of these developments and describes how coalbed methane, which used to be a bane, has become a boon for the coalmining industry.

Jan 1, 2003

By J. Y. Kim, R. W. Stanley, L. Rosato

Silver contained in zinc calcines undergoes several phase changes as it proceeds through the leaching circuit of a roast-leach-electrowin zinc plant. In this study, the flotation response of silver, from leach residues prepared under a variety of carefully controlled operating conditions in the pilot plant has been examined. Flotation of neutral leach residue is shown to be technically viable and to merit consideration for those plants without a high-acid leach circuit, but having significant silver values in the feed. Residue leach conditions must be kept slightly acidic to promote the formation of Ag2S, (AgCu) 2S and Ag2S rims on residual unroasted sphalerite, while simultaneously avoiding the hydrolysis of soluble iron, which depresses silver recovery and grade. Factors to be considered during integration of a flotation process into an electrolytic zinc plant are discussed.

Jan 1, 1992