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By Robin J. Hickson

The Ortiz Mine is operated by Gold Fields Mining Corporation, a subsidiary of Consolidated Gold Fields Ltd., one of the world's major gold producers. The Ortiz Mine is Gold Fields only heap leaching facility as well as being their first operating mine in the U.S.A. The hydrometallurgical processes utilized for recovery of gold and silver at Ortiz are discussed along with the several practical changes in operation adopted since start-up. Included are heap leaching by cyanidation, concentration of values on activated carbon, desorption, and the final electrowinning steps prior to shipment. Construction costs and pertinent technical data are shown.

Jan 1, 1981

By Douglas W. Huber

During the past decade, a general awareness of the need for and subsequent development of increased safety in United States coal mines has taken place. Government and industry alike were stimulated into accelerating their actions through unacceptable accident statistics and costs (in terms of human misery dollar values). Those of us who work in the United States coal industry are aware of the development of governmental controls on nine safety. Both Federal and State regulations have placed increased responsibility upon mine owners and operators to insure a safe working environment and to provide training for miners. No other industrial group of workers has received such attention or, in our opinion, deserves it more.

Jan 1, 1982

By A. A. Dor

Recent developments in the design of concentration plants have reflected the increased recognition that has been given to the economic and metallurgical advantages of autogenous grinding. This has manifested itself in the increasing adoption of primary auto genous grinding in iron ore 'beneficiation plants in North America. Table 1 lists eleven major iron ore beneficiation plants which have either been put in operation since 1961 or are under construction at present. Seven out of these eleven plants have adopted primary autogenous grinding. Four of them have coarse grinding mills (8 to 14 mesh) and three have fine grinding primary circuits (48 to 65 mesh). Their nominal capacity totals 26. 2 million ltpy of concentrates or pellets, representing very nearly 75% of the aggregate capacity 135. 3 million ltpy) of the eleven concentrators listed. For a long time there was a tendency to consider that primary autogenous grinding was only applicable to suitable coarse grained ores, However, extensive testing of a very wide variety of ores, and actual operating performance in several commercial plants, seem to have established beyond reasonable doubt, that the majority of mineral ores which the beneficiation engineer may be called upon to process can be ground autogenously. The basis for the selection of autogenous or conventional grinding mills, becomes principally economic and depends on the liberation characteristics of the ores under consideration and their relative hardness and grindability.

Jan 1, 1965

By Edwin B. Wilson

The purpose of the panel's examination of coal mining research and development is to explore how the various groups that make up this research community might work together more efficiently and be more productive. The community, as defined here, includes federal and state governments, coal producers, manufacturers, unions, universities, and industry sponsored research organizations. The framework chosen for these discussions consists of brief presentations by the panel members on their views of the proper role and function of the group they represent. The panel members were also asked to highlight the economic, technical and institutional constraints that affect the performance of research and development and the use of the results. Following these presentations, a number of prepared questions will be discussed by the panel, and audience participation is invited. These questions were given several weeks ago to the panel members for their study. Before proceeding with the panel member reports, a brief review of the importance of R&D to the coal mining industry would be helpful to setting the stage for a constructive dialogue. It is appropriate to begin this review by mentioning that there is complete agreement among the research community that the major goals are: Improve health and safety Protect the environment Increase capital and labor productivity Increase resource recovery Since the basic functions of the academic, industrial and government sectors are different, we should expect that the research and development objectives and priorities, roles and responsibilities under each major goal will be different for each research group. The differences do not represent problem areas. However, problems will arise if the objectives are not properly interfaced at the appropriate time. The consequences of railing to understand the need for integrated programs will be the classic result, best described by the phrase --"a technical success but a commercial failure."

Jan 1, 1978

Recent expansion programs have made the Yunkang underground coal mine the number one producer in Shenxi Province. The mine is the newest in the Datong Coal Administration, currently rated at around 3 Mt/a of coal. Located in the Wa Chushi mountain range about 23 km north of the city of Datong, the mine has undergone a series of expansion phases since startup in 1973. Initial design capacity was 1.5 Mt/a and ultimately, production will be brought to an estimated 7.0 Mt/a by 1985, according to mine superintendent Li Jia-zhi. How Coal Occurs The coal, Jurassic in age, occurs in three economically identifiable seams designated No. 2, 3, and 7. Seams are 100-250 m below the surface. Reserves from this economic zone were not quantified, but Superintendent Li indicated that there was enough mapped out to sustain the expanded production rate for over 20 years. Below the Jurassic coal is another possible economic zone, a Permocarboniferous coal lying 400-600 m below the surface. Little development drilling has been conducted to ascertain its potential. The Jurassic beds are relatively flat and coal quality is reportedly one of the best in China. Heat content of the coal runs around 33.5 MJ/kg and the ash content is less than 10%. In some areas, it is less than 7%. Coal preparation is simple and involves a washing and screening separation into four principal size fractions. Washed coal is stored in one of six storage silos, each with 4000-t capacity. Mining the No. 2 Seam Since startup, primary production has been derived from the No. 2 seam. The coal is relatively hard and is topped by a hard cement-like conglomerate. These factors, coupled with an average thickness between 4 to 6 m, precluded the use of conventional longwall techniques, according to mine engineers. The solution was development of a room-and-pillar tech-

Jan 3, 1980

By A. W. Dickerson

Following on from many years of research aimed at improving the effectiveness of truck haulage operations in mines operated by BHP Minerals, BHP Research developed a concept for an Innovative Large Mining Truck, (ILMT) which has the potential to significantly improve the cost effectiveness of rear dump mining trucks. The ILMT concept reduces the empty vehicle weight dramatically, greatly reduces unequal rear tyre loading and improves ride and handling characteristics. The concept has been taken to the "proof of concept" prototype truck stage with the cooperative efforts of BHP Coal, BHP Research, Liebherr Mining Truck, Inc., Liebherr-Australia and Birrana Engineering. Testing of the prototype truck commenced at a coal mine in Queensland, Australia during May 1996. Preliminary results from the testing program are very encouraging. Expectations are being met and in some cases exceeded.

Jan 1, 1997

By T. R. West

Planning for urban development in many locations is based largely on 0.10 factors, 1) soil conditions and 2) socio-political aspects of the region. A more widely based approach is necessary, however, if a complete and functional plan is to be obtained. Under this unified approach, the overall field of earth science is included in the planning process. As considered here, the earth sciences comprise a large segment of the natural sciences; that is, geology, pedology, geomorphology, reengineering geology and ground water hydrology. A number of shortcomings can develop when using the restrictive, two-factor approach for urban development planning. These deficiencies are discussed in the paper. The specific considerations for each earth science area are examined and land use considerations for various urban requirements reviewed in light of these specialties. To illustrate the potential of the unified or earth science approach, Tippecanoe County, Indiana is presented as an example. The current area planning system for Tippecanoe County is examined to determine how well it compares with the unified approach and some of the shortcomings of the current plans are discussed.

Jan 1, 1972

By Robert C. Maxton

The foundry industry is a basic source of structural component for all industry. Millions of tons of castings are produced annually in both ferrous and nonferrous alloys. These castings are subjected to a wide variety of heat treatments, finishing techniques, mechanical tests and machining operations. Through all of these steps the quality of the casting is of paramount importance to the end use of the product. The Quality Assurance Program at Minneapolis Electric Steel Castings Company is designed and established to provide a superior product for both original equipment manufacturers and the mining industry.

Jan 1, 1982

By C. D. Taylor, A. L. Mazzella, A. L. Martikainen

In fluctuating airflow, continuous air velocity recording is the most reliable method of air velocity measurement. It allows for fast recognition of changes and the calculation of long-term averages. Also, it enables the mine operator to identify when the airflow has decreased to a point requiring action. Using ultrasonic anemometers provides an accurate option for continuous air velocity monitoring. This paper provides information about the effect of common obstructions in underground mining on air velocity readings. Stationary and moving obstructions are used to represent workers and equipment that would cause discrepancies in measured airflow. Also, it is important to know how large of a sample size is required to ensure reasonable accuracy of results. Statistical analysis is used to evaluate the required sample size. The sampling procedure is further studied by comparing two different sample rates. The results show that obstructions provide noticeable differences in air velocity measurements. Also, movement of obstructions can be recognized from changes in results. Surprisingly small sample sizes provide reliable air velocity information. Standard sample rates are found to be suitable for the underground environment.

Jan 1, 2011

By R. A. Wyman

What unusual features are there about finding, winning, and using the industrial minerals of Canada which may be of interest and yet not widely known. Have you, for example, ever wondered where the raw material for those distinctive greenish grey statuettes, so readily recognizable as Eskimo carvings, comes from? Although stone suitable for carving is obtained at several northern locations, in recent years the Federal government, the Quebec government, and one or two private companies have shipped supplies of various rock types from other sources to central distribution points in the Canadian north for the express purpose of providing Eskimo artists with raw materials for carving. Canada is well endowed with industrial minerals, the extent and variety of which may be observed by a perusal of Table 1. In this table, materials currently produced are shown in the left-hand column; materials which are bordering upon economic viability are listed in the middle column; and materials which have been found in Canada in possible exploitable quantity, but for which [ ]

Jan 1, 1970

By I. Demers, A. Blier, M. Mbonimpa, M. Benzaazoua, B. Bussière

The Doyon Mine in Quebec, Canada, evaluates the possibility of desulfurizing its tailings to produce material to be used as cover for the acid-generating tailings disposal site. Laboratory tests showed that a single-layer cover made of desulfurized tailings placed over reactive tailings can prevent the generation of acid mine drainage. Modeling with the software Vadose/W was used to optimize the design parameters, namely, cover thickness, water table position and residual sulfide content of desulfurized tailings following laboratory work. It was found that the optimal configuration includes a 1-m (3.3-ft) desulfurized tailings cover containing 0.8% S, with the water table kept at the interface between the reactive tailings and the cover. To maintain the cover performance to reduce oxygen flux toward acid-generating tailings even in the event of a long dry period, a sand layer is suggested to protect the cover from excessive evaporation. It is possible to reach the environmental objective for oxygen flux chosen for the Doyon Mine (10 mol/ m2/year) with the protective sand layer, even in extremely dry conditions.

Jan 1, 2009

By Tom H. W. Loomis

The department of the Interior is a federation or holding company of several fiercely independent bureaus which have either jurisdiction or expertise - or both - in a wide range of environmental fields. Each bureau is an advocate for its own concerns and an enforcer of its own mandates. This can be confusing to the company operating in the field. I will try to explain our concerns, help you see where we are "coming from," and give you some insight as to how we can help you. Other speakers have stressed the environmental concerns and site selection factors for uranium wastes so I will focus on the concerns of the Department of the Interior and some of the assistance we can give you in this area People are more aware and more concerned about environmental factors now than they used to be. Thus the past decade has brought about an evolution in both siting and design of uranium mill tailings ponds. Site selection criteria used to be simple - find a tract of land as near to the ore supply as possible with enough space and suitable topography for the expected volume of wastes. Site selections in the past have left a legacy of problems to be corrected - radioactive wastes on stream banks and in floodplains, mill wastes in and near established communities, and unprotected wastes subject to constant erosion. This is no longer acceptable environmentally or socially to a newly aware and concerned public. (Series of 30-35 slides showing uranium mine and mill wastes in Western United States. These illustrate environmental problems, reclamation and environmentally acceptable sites. The first group of slides are aerial shots taken in Wyoming and shows a surface mine and mill area. In the various views the pit, overburden piles, mill, and tailings pond can be seen. The next series were taken in Wyoming and New Mexico. These show various views

Jan 1, 1980

By V. E. Housman

EPA's Mining Waste Section within the Office of Solid Waste is continuing to collect and analyze information on mining waste management practices. Starting in 1991, the Mining Waste Section has continued to conduct site visits and prepare case study reports on the waste generation and management practices of operating mines. In choosing sites to study, a reasonable attempt was made to provide diversity in mining commodity types, geographic regions, geology, climate, and environment. To date, EPA has visited the following mines: Asarco Troy (copper) in Montana, Newmont Rain in Nevada (gold), Cyprus Thompson Creek (molybdenum) in Idaho, LTV Steel (iron) in Minnesota, Phelps Dodge Morenci (copper) in Arizona, Doe Run Fletcher (lead) in Missouri, Brewer (gold) in South Carolina, IMC Four Corners (phosphate) .in Florida, Pennzoil Culberson (sulfur) in Texas, Nerco Cripple Creek (gold) in Colorado, Copper Range White Pine (copper) in Michigan, Magma San Manuel (copper) in Arizona, Colosseum (gold) in California, and several gold placer mines in Alaska, including the Valdez Creek Mine. EPA has prepared a case study report on each facility. The mine operators were provided an opportunity to comment on their respective site visit report and their comments have been included in' each respective report. These site visit reports have in turn been incorporated into technical resource documents which provide a detailed description of each mining sector. EPA is currently reviewing the technical resource documents and plans to release the documents in the Spring of 1994.

Jan 1, 1994

By M. Sears, G. S. Esterhuizen, Z. Khademian

According to the 2010-2019 Mine Safety and Health Administration (MSHA) accident report database, 91% of reported ground control accidents in U.S. longwall mines were caused by roof instability. Gateroads are subject to significant changes in loading conditions from the development to the longwall abutment loading phases. When combined with thinly bedded shale roof, found in many U.S. longwall coal mines, the design of efficient roof support becomes challenging. In previous work, the Bonded Block Method (BBM) modeling of roof by UDEC was validated against field extensometer measurements in a longwall gateroad entry roof at a 180-m depth of cover. The BBM was shown as capable of capturing delamination and buckling of shale roof, one of the main roof instability mechanisms in longwall mines. This paper presents the recent findings on the roof-support interaction using BBM models of the same longwall entry. The effects of cable bolts, roof bolt density, and strap support on potential roof instability are studied. These types of studies are difficult and costly to conduct in an operating mine. Results show how the contribution of bolts, straps, and cable bolts can be quantified using the BBM models. The study demonstrates the potential for BBM numerical models to help understand the complex roof and support system interactions and to assist with optimizing gateroad support systems.

Feb 1, 2023

By R. J. Sweigard

Many states are considering the need to establish or modify policy relating to the disposal of coal ash. One of the primary concerns is the impact of leachate from the ash disposal sites upon groundwater and nearby bodies of surface water. A detailed site investigation was conducted at a coal ash disposal facility associated with a power generation station. The disposal site is situated alongside a major river. Monitoring wells were installed and soil samples were taken for characterization. Groundwater models were used to simulate migration of leachate from the disposal site toward the river. Such models could be used potentially to verify regulatory compliance. This paper addresses the validation and adaptability of these models to this case and their usefulness as possible tools to be used in future environmental audits.

Jan 1, 1992

By Francesco Chiappalone, Marco Invernizzi, Franco Gasperin, Fabrizio Fara

As part of the Ship Canal Water Quality Project, 2.7-mile Combined Sewer Overflow tunnel is excavated with a 21.5-foot diameter EPB Tunnel Boring Machine. Due to the difficult geological and hydrogeological conditions, the tunnel is excavated maintaining a ground support pressure between 1 and 3 bar imposing significant challenges to the projects. The first part of the paper describes the general characteristics of the project while the second part focuses on the challenges and technical details of the pressurized breakthrough that took place in a deep shaft excavated in urban environment as part of the project.

Jun 23, 2024

By Jim Johnson

The purpose of this paper is to summarize and discuss a variety of site specific conditions which are typically evaluated as part of the engineering design process for heap leach pads, solution control ponds, and associated facilities. The following sections will focus primarily on the topographic, climatologic, hydrologic, and geotechnical evaluations critical to selection of heap leach sites, and selection of a preferred heap leach configuration or method. Other important considerations in the design of a heap leach project, including evaluation of ore properties and leachability, pregnant solution processing requirements, spent ore neutralization/disposal requirements, and other anticipated reclamation requirements are beyond the scope of this paper are not addressed in any detail.

Jan 1, 1998

By S. J. Schatzel, J. D. Addis, V. Gangrade, L. L. Chasko, C. A. Hollerich

"A ventilation study using tracer gas was conducted at a western US coal mine. The objective of the study was to evaluate the movement of longwall face air exchanges between the face and worked-out area and to document the presence or absence of face airflow pathways between these locations. The mine operator uses a bleederless longwall ventilation system with a back return and a blowing mine ventilation system. The study was conducted on an active panel and included both underground and surface monitoring sites. The study used sulfur hexafluoride (SF6) released as a slug on the longwall face and in the front of the gob inby the face. The velocity of the tracer gas movement in the gob was 0.019 m/s (3.7 fpm). The rate of movement for the overall tracer gas slug averaged about 0.0091 m/s (1.8 fpm). A separate tracer gas test initiated with the release of SF6 into the legs of the first shield showed the existence of more than one pathway of face air in the general direction from the headgate towards the tailgate corner. Maintaining adequate ventilation air on longwall faces is important for worker safety and for the dilution of methane emitted from the face and caved gob. A more detailed characterization of longwall system air and gas movement allows a mine to better assess its ventilation design for controlling gas on the face and in the gob. INTRODUCTION During a series of stakeholder meetings, a near unanimous concern was expressed related to maintenance of effective ventilation airflow on longwall faces. There was a strong interest expressed regarding the impacts of face length and caving characteristics on the ability to maintain adequate face airflow levels. This study seeks to understand and improve a mine operator’s ability to monitor and control ventilation and methane concentrations across the longwall face by assessing airflow variations in terms of roof caving characteristics and face length. National Institute for Occupational Safety and Health (NIOSH) researchers seek to identify flow paths of ventilation airflow on longwall panels with variations in roof caving characteristics and longwall face lengths. The project research aims to develop an understanding of the role of gas dynamics in variable broken rock, interactions with ventilation airflow and methane concentrations across the longwall face area. The research also addresses continuous ventilation monitoring along the shield line to provide early detection of gas exchanges between face and gob, and thus improve a mine operator’s ability to monitor and control ventilation and methane concentrations around the face. In the context of this paper, the longwall gob refers to the pillared area behind the shields. This work reports on results from one project task to conduct field based research using a tracer gas to describe face air and gob area gas movement in a bleederless longwall ventilation system that incorporated a back return."

Jan 1, 2017

By J. R. Batista

Leachates from gold heap-leaching mines contain selenium concentrations as high as 2 mg/L. Previous studies report satisfactory selenium adsorption by activated alumina when using relatively "clean" drinking waters. However, the findings of these studies cannot be directly applied to the treatment of mine leachate where other ions compete for the alumina adsorption sites. This study evaluated the adsorption of selenium from a mine leachate to develop design parameters for full-scale activated alumina processes. The study revealed that 68% of the selenium in the leachate could be removed by alumina at pH > 5.0. Silica adversely affected the selenium adsorption capacity. At pH values < 4, silica was poorly adsorbed by alumina and selenium adsorption was improved.

Jan 1, 1994

By Russell G. Slayback

An integral part of site investigations for shafts and underground workings should be hydrogeologic evaluations of the need for and method of ground-water control. Such investigations should include: 1. Classification of the problem by aquifer type. 2. Integration of other site investigations with hydrogeologic programs, including assessment of the need for water control. 3. Planning and conduct of aquifer tests tailored to the aquifer situation. 4. Evaluation of pumping requirements to achieve water control objectives. 5. Scheduling of dewatering for optimum results and costs. 6. Evaluation of environmental impacts of pumpage and water discharge. 7. Planning of operational monitoring for program modification and liability limitation. Early hydrogeologic involvement can result in avoiding unnecessary duplication in site investigations.

Jan 1, 1981