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By Palmer C. Sweet

By-products from mining and processing plants and coal-fired power plants are being utilized more as valuable resources in Virginia. Mining-related by- products are divided into two categories: those generated from mineral extraction and beneficiation, and those generated from mineral processing or from industrial plants. Materials from both categories are produced in Virginia, where by-products have been exploited for various uses in the past and/or present. These materials include coal- combustion products (fly ash and bottom ash), lime-kiln dust, flue-gas-desulfurization residue, rock fines, magnetite, Cold Spring clay (kaolin), Austinville tailings, soapstone rock, and calcium-carbonate paste. Some of these by-products have never been utilized, although several ideas have been investigated over the years.

Jan 1, 1999

By Matthew E. Fowler, Jean Habimana, Roy F. Cook

The West Side CSO Tunnel, Pump Station & Pipeline Project is currently beginning construction along the downtown waterfront of Portland, Oregon. This4.3 meter diameter, 5,500 meter-long soft ground tunnel will be driven along the westbank of the Willamette River adjacent to buildings and utilities and several major pile-supported bridges. High groundwater pressure, extended lengths of gravel to cobble-size alluvium, and the need to control ground loss and surface settlements were key considerations in the selection of slurry tunnel boring machines for the project This paper presents an overview of the numerical modeling that was performed during design to estimate the strains and additional loads in the pile-supported structures and to assess the efficiency of proposed mitigation measures.

Jan 1, 2003

By K. G. Tan

Widely available silver and arsenic bearing concentrates can be smelted to produce a discardable slag, a base metal speiss, and a crude silver button which is easily separated from the other phases after solidification. This paper discusses the development of a novel process as an alternative to existing nitric acid leach methods for the production of high purity silver from the raw silver button. Direct electro-refining of the raw silver anode in a sulphate medium is integrated with downstream purification and recycling modules that are customized to allow efficient recovery of silver and saleable by­products. The test results, flowsheet alternatives and process details are presented and discussed in terms of overall technical feasibility, economical viability and environmental compliance considerations.

Jan 1, 1999

By Ron VanRiper, Ben W. Burdett, Randy A. Ynchausti, Jeff D. McKay, Dan Lampshire, Thomas W. Toronto

An adaptive process control system was installed in Cortez Gold Mines Mill #2 Grinding Plant in Nevada. The installation, commissioning, and testing of the system took approximately 80 manweeks, but final test results show that the system paid for itself through increased throughput within two weeks of commissioning. Both crisp and fuzzy rules are used in the expert rule base which is also integrated with continually adapting neural network models. The expert rules and models are used by predictors, and optimizers to allow the control system to provide optimum process performance under continually varying feed conditions. The selection, installation, rule and predictor configuration, and statistically verifiable testing of the control system in the Cortez Gold Mines Mill #2 Grinding Plant is described in the paper.

Jan 1, 1999

By L. Lichty

Treatment of refractory gold ores containing arsenic has always presented a major problem in their processing to recover the contained precious metal values. The major difficulties are concerned with lower recoveries and production of hazardous fumes, effluents and residues. Due to these arsenic related problems, many otherwise economically attractive precious metal deposits and dumps all over the world are not exploited. In recent years, treatment processes for refractory gold ores and concentrates have been explored. A few commercial operations employing roasting or pressure leaching have resulted. Roasting has limitations due to environmental constraints related to off gases. Pressure leaching involving high temperatures (180° to 200° C or 356° to 392° F) and pressures (2.75 MPa or 400 psi) is accompanied by high capital and operating costs.

Jan 1, 1990

By J. Chappell

The Nuggety Gully prospect is located 170 km (106 miles) south- east of Port Hedland and 40 km (25 miles) northeast of Marble Bar in the Pilbara Region, Western Australia. The area is held under title by Esso Exploration and Production Australia, Inc. The prospect covers a significant, but currently uneconomic body of molybdenum and copper mineralization of porphyry style, associated with Archean high level acid intrusives intruding sediments and volcanics of a narrow east-west Archean greenstone belt. The Nuggety Gully intrusive rocks have been dated at 3.2 b.y. ± 117 (de Later, oral communication). The current resource estimate for the deposit is 102 Mt (1 12 million st) of 0.1 1 % Mo and 0.15% Cu.

Jan 1, 1991

By M. C. Rockwell

There are about 1.8 Mt (2 million st) of discarded dolomitic-limestone tailings from the Gays River lead/zinc mining operation in Nova Scotia currently stockpiled in a tailings pond at the mill site. Neutralization effectiveness similar to an agricultural grade limestone and low contents of residual metals make the tailings a potential source of soil conditioner material for the local market. However, the fine particle size, 98% passing 147 pm (about 100 mesh), and a moisture content of 20% make their handling, shipping, and application to soils difficult. The tailings were agglomerated into small hard pellets with various amounts of soil nutrients, moisture content less than 13%, and pH values ranging from 6.5 to 8.7.

Jan 1, 1987

By Colin M. Kelly

The Loveridge Mine, located near Fairmont, West Virginia, has been mining coal from the Pittsburgh Seam since 1958. As the mine develops its reserves it finds itself with increasingly distant hauls from the operating faces to the preparation plant. Initially, the mine was designed with track haulage. The coal was hauled to an underground rotary dump which fed a slope belt, to the preparation plant. As the haulage distances increased, production delays due to the track system's limitations became severe. To resolve this situation, a complete review of the haulage system was undertaken. Simulations of the present system along with future scenarios were conducted to help management effectively plan the haulage requirements of the mine for the remainder of its life.

Jan 1, 1986

By Bruce A. McKinstry

For many major mining projects the time frame from initial planning to production can be measured in terms of decades. Hecla's Silver Shaft project, which is scheduled to go into production by the end of this year and includes a complete surface facility, shaft with an ultimate depth of 2,348 meters (7,700 feet), complete ore pass and loading pocket system, and 610 meters (2,000 feet) of development drifting and stope preparation, was initially concieved in the Fall of 1979. This duration of a mere four years from conceptual engineering to production is a testimonial to what can be accomplished when a progressive mining company and an innovative contractor work together as a team rather than developing into two warring camps as often happens.

Jan 1, 1983

By Michel Grenier, David A. Young, Brent Rubeli, Mahe Gangal

This work forms part of a study being conducted into the feasibility of constructing a prototype Load Haul Dump (LHD) vehicle for operation in underground Canadian mines. A series of in-laboratory assessments were performed to determine the relative contributions of a Deutz F4L912W (54 HP- conventional vehicle engine) and a Deutz F2L 2011 (31 HP hybrid vehicle engine) to diesel emissions concentration during mine transient duty cycles and steady-state operating modes respectively. Results indicate significant reductions in the quantity of gaseous and particulate emissions with the application of the hybrid system and a high-efficiency ceramic element filter. This paper describes the engine test protocols and the results of this laboratory study.

Jan 1, 2006

By Wolfgang H. Roth, Stephen J. Navin, Samuel K. Louis, Anthony F. Stirbys

This paper presents a case history of the design and construction of the access shaft and cross adit utilized to gain access to the Los Angeles Metro Rail tunnel alignment, at the A146 Contract site. The access shaft, a 14 m (45 ft) inside diameter structure, was constructed using ring beams and lagging with concrete backfill to a depth of 18.59 m (61 ft). The cross adit was hand excavated in sequential benches using liner plate, arch ring beams, and posts for support. The sequence of excavation and support placement are discussed. Soil conditions encountered at the project site are discussed together with the development of the design criteria. Instrumentation data collected during the excavation are also presented.

Jan 1, 1989

By Kenneth R. Dickson, I. Michael Gowring

This paper describes the underground work associated with the North Fork Stanislaus River Hydroelectric Development currently being constructed by Sierra Constructors for the Calaveras County Water District in California under a turnkey contract. Sierra Constructors is a joint venture of the Guy F. Atkinson Construction Company (sponsor) of South San Francisco, and the Harrison Western Corporation of Denver. Notable features of this project include the exceptionally high performance achieved by the 5.5m diameter Robbins tunneling machine and the 675m deep shaft pilot hole which was successfully realigned using oilfield directional drilling techniques. Other features include 3.7m and 4.3m diameter machine-excavated tunnels and various conventionally excavated tunnels constructed over a wide geographical area and diverse climatic conditions.

Jan 1, 1987

By Jack R. Nawrot, R. E. Lounsbury

Preservation and replacement of wetland habitat has become a National priority. Lands affected by mining can provide an excellent opportunity to develop wetlands where none currently exist. This proposed end use for land can require converting quality farm land from its pre-mining farming capability. Where such conversion is necessary, environmental regulatory authorities in lllinois have come to view wetlands among the preferred restoration alternatives. Research and large scale demonstration projects conducted by the Cooperative Wildlife Research Laboratory at Southern lllinois University at Carbondale have shown that coal slurry ponds can be reclaimed to wetlands. Key to successful wetland establishment is recognizing distinct zones in the slurry surface to be vegetated and treating these zones with appropriate soil amendments and plants.

Jan 1, 1991

This section is addressed to the computing needs of corporate (top) management which are less specialized than the computing needs of operating or divisional management described in the previous sections. It is essential that the computer be used as a tool to serve corporate management and that information and results are presented in a succinct form. A key responsibility of the manager of computer applications is to communicate well with corporate management. A common trap for computer management is to allow the development and implementation of sophisticated and academically interesting computer applications which do not enlighten corporate management in its decision-making task. Thus it is essential to devote sufficient time and effort to designing and specifying a computer system before developing and implementing the system.

Jan 1, 1979

By G. H. Jardine

Mine planning and production scheduling in surface mines are basically iterative processes which are ideally suited to the use of computer-based techniques. Both processes are truly three-dimensional and lend themselves to the application of 3-D interactive graphics. Until recently, this has applied the need for the costly, dedicated graphics screens and mid range minicomputers. However, ongoing advances in processor chip design led to the emergence of inexpensive and powerful 5 to 10 Mips desktop work- stations. These workstations have the processing power to support rapid, high resolution, 3-dimensional graphics. By combining these workstations with powerful 3-D CAD software and, with a suite of comprehensive mine planning and scheduling applications, Mincom has developed a most cost effective solution to modern mine planning challenges.

Jan 1, 1989

By John E. Urosek, Herman Schade

In March, 1988, a fire occurred in a large underground coal mine. Coal Mine Safety and Health of the Mine Safety and Health Administration was immediately notified of the situation. They requested the assistance of the Pittsburgh Health Technology Center (PHTC) to provide monitoring and analysis of the mine atmosphere in and around the fire area to insure the safety of the miners escaping from the mine and for the miners involved in extinguishing the fire. The capability to provide this type assistance is maintained by the PHTC Offices located at 4800 Forbes Avenue, Pittsburgh, Pennsylvania. The equipment used is maintained field ready and can be mobilized almost immediately. This paper will discuss the response to this recent major mine fire.

Jan 1, 1989

By K. H. McDaniel, D. M. Loring

The underground ventilation system at the Waste Isolation Pilot Plant (WIPP) provides for the unparalleled ability to ensure the safety of the workers, the public and the environment. Although small spatially, the system can vary the airflow from 31.2 to 217.1 m3/s (66,000 to 460,000 cfm). The system can automatically incorporate HEPA filtration in the event of radioactive contamination. Remote-capable regulators individually control the four main splits, and they can be adjusted from the surface if necessary. A ventilation remote-monitoring and control system provides real-time information. Future areas of concern include DPM compliance, system psychrometry, logic-based real-time mine-ventilation simulation and automation using PLC technology. This paper discusses the evolution of this system.

Jan 1, 2003

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 I. Iwasaki, K. A. Smith, X. Cheng

A cathodic decomposition model was examined for both pyrrhotite and chalcopyrite in an attempt to analyze the formation of surface coatings in deoxygenated solutions at natural, near neutral pH. Combination potentials established between the mineral-grinding media pair were simulated by applying a potential of -0.455 V (vs. a standard hydrogen electrode) either to a pyrrhotite or to a chalcopyrite electrode. Chronoamperometry was used to study the polarization behaviors and alteration of mineral surfaces through cathodic processes. The kinetic parameters of cathodic decomposition of pyrrhotite and chalcopyrite were determined and compared. It was concluded that pyrrhotite decomposed faster than chalcopyrite in near-neutral pH solutions. Both minerals were then covered by a film consist¬ing mainly of iron hydroxides, which adversely affected their flotation.

Jan 1, 1999

By K. S. E. Forssberg, K. Hanumantha Roa

Batch flotation tests are carried out with phosphatic material from LKAB, Sweden containing carbonatic and siliceous gangue while using sodium oleate as collector and sodium silicate as modifier. The pulp liquid is analysed for oleate, silicate, carbon dioxide, calcium, magnesium and phosphorous after each flotation test under different reagent conditions and flotation pH. Theoretical calculations of thermodynamic chemical equilibria in apatite-calcite-sodium oleate-sodium silicate system have been carried out with the help of SOLGASWATER computer program. During the calculations, the chemical variables are maintained similar to the operating chemical variables in flotation. A comparision between the experimental and theoretical chemical equilibria has been made and the flotation behaviour of apatite is discussed with reference to the theoretically calculated pulp model.

Jan 1, 1993