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By Janusz Szywacz, Bozena Bojko, Stanislaw Wasilewski

Two groups of computer programs are described in the paper. First one is the OWEN system containing software modules designed for air flow distribution analysis and prediction within the whole ventilation network of a mine. The second group is a set of programs commonly used in a routine design work connected with chosing the optimal ventilation schemes and equipment for individual areas of a mine (headings. longwall districts etc). All the programs are designed for running on the IBM PC/XT, IBM PC/AT and compatible computer systems.

Jan 1, 1989

Accidents that resulted in 16 deaths in three West Virginia coal mines, two in Kentucky and one in Utah have government and industry re-evaluating current safety regulations. Even though U.S. mines continue to improve on their safety records, the deaths reminded the industry and state and federal agencies that mining remains a dangerous business. Even so, data from the U.S. Mine Safety and Health Administration (MSHA) show that new technologies and a highly trained workforce has allowed the nation’s coal mines to increase production while providing safer workplaces. Since 1970, coal production at U.S. mines has increased by about 83 percent. During the same period, fatal injuries have fallen by 92 percent. And more than half of the U.S. coal mines operate each year without a lost-time injury. In 2005, there were 22 deaths in U.S. mines, a record low.

Jan 1, 2006

By R. L. Grayson, T. L. Dickinson, C. G. Anderson

Sponsored by the EPA, USGS, DOE, and NSF through the Committee on Earth Resources, the National Research Council’s Committee on Material Flows Accounting of Natural Resources, Products, and Residuals, created in August 2002, studied the value that material flows accounting, which can track the flow of a material from the time it is extracted to its ultimate disposal, may provide for making better integrated economic, social, and environmental policy decisions. This could be a crucial technology for the mining industry to incorporate. This paper will recount the statement of tasks, the study process, and the science-based conclusions and recommendations reached.

Jan 1, 2004

The thermal field of a frozen rockmass surrounding an airway is often disturbed due to thermal interaction with mine ventilation air. Outside air entering an underground mine changes the parameters of the physical state of the surrounding medium. The variations in air temperature result in stress redistributions around a tunnel or mine working. This paper examines the influence of fluctuations in air temperature on stress distribution around an airway, and approaches are suggested to minimize the impact of temperature- stress on the stability of mine openings in far northern mines.

Jan 1, 1991

By Michael Jatczak, Joseph A. Sopko

Ground Freezing was used for excavation support and groundwater control of a 12.8m (42-foot) diameter, 61m (200-foot) deep drop shaft for the South Bay Ocean Outfall Tunnel in San Diego, California. Approximately half way through the excavation, excessive groundwater inflows from the base of the shaft resulted in suspension of excavation and evaluation of the frozen earth wall. This paper discusses the forensic methods used to identify the zone where groundwater intrusion occurred and the methods associated with evaluating zones of high groundwater velocity. The use of remedial grouting and localized liquid nitrogen injection are discussed and evaluated. Concepts of frozen shaft design are discussed, including a new method for permitting the launch of the Tunnel Boring Machine through the frozen earth wall and associated freeze pipes.

Jan 1, 1999

By J. G. Wargo

In situ leaching of disseminate gold deposits has been studied from a theoretical perspective to outline the operating environment for the process. Rock permeability and the relationship of permeability to the site of gold particle deposition are key factors in predicting the efficiency of in situ leaching. Permeability measurements, however, have rarely been made during gold exploration, so that secondary geologic features of the deposit must be used. This paper examines some of the geologic characteristics of disseminated gold deposits and comments on the problems and possibilities of in situ leaching of gold.

Jan 1, 1987

By S. P. Liebenberg

During the past fifteen years significant progress has been made on carbon-in-pulp (CIP) technology for the extraction of gold. While most research on the mechanisms and kinetics of CIP sub-processes has focused on the adsorption step only, auxiliary unit operations such as elution have received less attention. The mathematical models which have been developed for elution at the University of Stellenbosch can be used for design as well as process optimisation by incorporation into an overall CIP simulation program. Except for these models, no other comprehensive models for the complex elution process are available. It is the aim of this paper to review recent modelling work on competitive elution from activated carbon.

Jan 1, 1995

By P. Sanchez-Mejorada

Quimica del Rey, SA, a subsidiary of Industrias Peñoles, SA de CV, produces sodium sulfate from brines extracted from a playa of Laguna del Rey, located in the State of Coahuila in northern Mexico. The spent brine is used as raw material for the production of magnesium oxide. The brine, which contains ions of sodium, magnesium, sulfate, and chlorine, occurs filling intercrystalline voids of a lenticular evaporite deposit whose main constituents are glauberite (sodium-calcium sulfate) and blöedite (sodium-magnesium sulfate).

Jan 1, 1987

By Don Stainbrook

Over a period of many years a highly automated computerized system of ore control has been developed at the Newmont Gold Company, (NGC). It is the purpose of this paper to review the development of this system, describe the setting in which it functions and to mention some of the future developments and enhancements. Discussion of the evolution of the system in a historical perspective helps to understand its present status and illuminate some thinking about future directions of development.

Jan 1, 1989

By William J. Kohan

Milling has traditionally been considered more art than science. In the last 10 years, significant improvements in process equipment have been made and we are finally taking significant steps toward approaching grinding as a science. Two machines have been at the center of this development. These are the roll press and the high efficiency separator. The former can be considered as a new technology or adaptation of existing i.e. roller mill. The latter is clearly an improvement of existing technology. Other machines have been introduced to a lesser degree and later. Among these are the CKP and Horomill. The purpose of this paper is to provide an over- view of the currently available modifications for operating systems and options for new milling circuits with some comments on their application and history.

Jan 1, 1997

By D. M. Larsen, N. D. King

Since start-up in 1985, the Cannon Mine has produced and shipped a 170-g/ton (5 oz/ton) gold flotation concentrate to various smelters for gold and silver recovery. Several processes have been investigated to economically produce dore' at the mine site from the refractory concentrate. This paper describes laboratory and pilot scale test work used in the process design and engineering feasibility study of a 73-t/d (80 stpd) pressure oxidation and carbon-in-leach (CIL) facility. The designed pressure oxidation circuit utilizes a series of vertical autoclave units operating at 170°C (338°F) and 1.4 MPa (200 psig). Projected operating costs are discussed.

Jan 1, 1994

By Greg Barfoot, Alex Harrison

Conveyors with multiple drive pulleys of the same diameter and wrap, driven by identical motors through gearboxes of the same ratio, consume different powers. The fundamental issues related to this problem hinge around the drive pulley co- efficient of friction and the intermediate tension. Some basic design concepts will be presented with reference to validity and applicability. The paper will describe some experimental results obtained from multiple drive conveyors in which the drives are spatially separated. The dynamics of tripper drive and linear booster drive systems are overviewed with reference t

Jan 1, 1993

By O. C. Carter, B. J. Scheiner

The Bureau of Mines is investigating the effects of rainfall and gypsum/cooling pond water on the rate of metal and nonmetal ion mobility through phosphogypsum stacks located in central Florida. Since leachate contains metal and nonmetal ions that have the potential for migration into surface and groundwater, laboratory column leach tests were conducted. Synthetic rainwater was passed through the column and metal and nonmetal ion migration was monitored. Similar experiments were conducted using a number of synthetic solutions which simulated a number of different compositions of gypsum/cooling pond water. Results indicate that within the first five pore volumes most of the mobile metals and nonmetals were removed.

Jan 1, 1992

By R. W. Reisinger

An historic underground copper mine in Wyoming is discharging neutral but copper-laden water into a pristine creek. The EPA-deferred site qualifies for reclamation by the Wyoming Abandoned Mine Land (AML) program. The cleanup goal is to restore the discharge so that the creek can eventually support a trout fishery. Hydrological and geochemical investigations underground have suggested two sources of mine water: one clean and the other containing copper. Results of bench-and pilot-scale tests support the viability of using low-cost passive treatment techniques to reduce copper concentrations in the near-freezing mine discharge.

Jan 1, 2000

By Simon T. Johnson, Robert J. Fowell

The application of roadheading and drag tool equipped machines requires an assessment of both cutting performance and tool consumption. Neither parameter can be assessed purely from compressive strength and tool consumption is often neglected, at a cost to the project. Results from in-situ monitoring show that a measurement of relative abrasivity using the Cercharscratch abrasivity test provides a basis for the assessment of tool consumption. This can be modified by also considering the effects of the machine specification and the rock mass quality.

Jan 1, 1986

By M. W. Chanda

This paper presents the development of a rock-creep measuring apparatus using air as the initial pressure source. Servo-controlled machines can and have been used for time-dependent property tests. However, the long-term nature of some tests makes essential the complete independence of stress-maintaining equipment from main power sources or continuously running hydraulic pumps. The main objective of this paper is the development of a creep testing machine that is free from interference arising through power supply interruptions or mechanical maintenance normally associated with many compression testing machines. To achieve this, a compressed-air power source was used to drive a compression ram. A few trial results obtained and analyzed using the transient creep law are in reasonable agreement with the general creep law.

Jan 1, 1993

By H. L. Owens, J. W. Fredland, K. K. Wu

The Mine Safety and Health Administration (MSHA) is responsible for reviewing and approving the engineering plans for impoundments, of significant size or hazard potential, that are constructed on coal-mine property. Over the years, technical review criteria have been updated as the state-of-the-practice for dam safety has evolved. The evaluation of stability under earthquake loading, for example, has gotten much more sophisticated for impoundments built using upstream construction. Recent incidents where slurry has broken into mine workings have caused MSHA, mine operators, and design engineers to re-examine this safety issue. This paper gives an overview of MSHA’s impoundment plan review process.

Jan 1, 2003

By Anna Arkhireeva, John N. Hay

Considerable interest has been shown recently in organically modified silicates (ormosils) because of the wide range of possible applications for these interesting organic-inorganic hybrids. These applications include the use of the hybrids as modifiers of a range of host polymer proper- ties. The ormosils can be synthesised by the conventional hydrolytic sol-gel process, as well as by the non-hydrolytic sol-gel route. To date, however, there are relatively few reports of the synthesis of sub-micron size ormosil particles of well-defined spherical morphology. Here, we report work to date on synthesis of such nanoparticles and also introduce our own work in the area.

Jan 1, 2003

By L. Buckingham

Barrick Goldstrike Mines Inc. has embarked on a continuous improvement effort to ensure that Barrick Gold Corporation will retain its lead in the gold industry in years to come. The continuous improvement initiative is based on careful mapping of the key levers associated with each activity of business. The individual levers are then evaluated to determine their potential to affect the profitability and safety of the operation. The most promising are diagnosed for root causes. These root causes are then addressed to enhance benefits. Through a structured approach of mapping, brainstorming, evaluating and instigating change with follow up measurement and reporting; Barrick Goldstrike is anticipating an increase in throughput at the autoclave facility of 10% with little or no capital expenditure. The resultant approach to Continuous Improvement will be utilized throughout the Goldstrike facility and then throughout Barrick's world-wide operations.

Jan 1, 2002

By N. M. Grant, W. G. Prast

Jamaica has extensive deposits of marble, gypsum, and limestone, offering prospects for commercial sales to nearby US markets, notably the Gulf Coast and Southeast. Stare-owned and private Jamaican industrial minerals producers have made limited sales to date but expect to increase exports during the balance of the 1980s. Restraints include Jamaican government controls on access to essential foreign exchange for new capital investments and distribution of profits. Jamaican efforts to identify market opportunities in the US are reviewed, and the outlook for further exports of carbonates is discussed.

Jan 1, 1987