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By G. J. Olson

This paper describes the microbiology basics underlying heap and tank biooxidation of metal sulfide ores and concentrates. The primary organisms are identified and described along with the reactions they catalyze and their growth requirements. Also described is the interaction between ore leaching bacteria and the leaching environment in terms of solution chemistry, temperature, and mineral precipitation. Specific factors and agents that stimulate or inhibit growth and activity of ore bioleaching will be identified. Some of these factors are organism-specific and others are generic for microorganisms that grow under acidic conditions. Current knowledge of the limits of bioleaching in terms of dissolved ions in leach solutions, pH, and temperature will be summarized.

Jan 1, 2003

By A. W. Czarnowsky

More than ever before, mining projects are besieged from growing regulatory, political, public, and special interest group pressure. Administrative and legal appeals to permits and environmental documents can delay project start-up and add tremendous cost to mineral development. Some mining projects have been canceled given undue external constraints. Successful managers must learn to cope with these constraints. This paper will discuss controversy and present a number of environmental management tips to minimize the potentials for delay and to lessen the impacts from government and anti-mining pressures.

Jan 1, 2001

After several years of laboratory and field evaluations, it has been established that each frother has its own unique relationship among bubble size reduction, gas hold-up increase, froth stabilization and frother concentration. It has been shown that a frother?s hydrodynamic properties can be characterized using the relationship between the froth zone property froth height and the pulp zone property gas hold-up. The relationship is established in a bubble column run at a given air rate over a range of frother concentration. The use of relationships in frother selection and plant diagnostics is illustrated in a series of plant case studies.

Jan 1, 2009

By M. Hancer, J. D. Miller

The sign of the surface charge of selected potassium soluble salt minerals namely KClO4 , K2SO4 , KNO3, and KCl was determined from nonequilibrium electrophoresis measurements and found to be negative for each of the salt. Dodecylamine flotation of these salts revealed that the concentration of amine required for flotation increases in the order KClO4< K2SO4< KNO3<KCl. Precipitationof the amine collector colloid was not required for flotation of the oxyanion salts and in this case it appears that adsorption of the dodecylamine cation is sufficient to create the hydrophobic surface state. The order for flotation is explained in terms of surface hydration of these respective potassium salts based on contact angle measurements and FT Raman spectroscopic characterization of water structure.

Jan 1, 1999

By Donald W. Gentry

This paper presents some of the results of a rock mechanics in¬strumentation program designed for, and implemented at, longwall panel 4N at the York Canyon Mine near Raton, New Mexico. The objective of this particular instrumentation program was to determine the response of the rock mass to longwall mining of a thick coal seam utilizing shield-type supports. Measurements were made in the rock along the ground surface, above the coal seam, in the coal seam and immediately below the coal seam. Longwall test panel 411 had a total developed length of 762 m (2500 ft) and a face width of 168 m (550 ft). The seam mining height in the panel area was approximately 3 m (10 ft). The average depth of overburden above the panel is 107 m (350 ft) al¬though it ranges from 73-134 m (240 - 440 ft). Roof support at the face was provided by Hemscheidt shields. These shield-type supports weigh 11.4 metric tons each.

Jan 1, 1977

By C. Ford, R. E. Salas Rojas, J. P. Contreras Rodriquez, S. A. Pierce

Heightened environmental consciousness has resulted in the development of various international accords dealing with natural resource management. This international awareness is now being translated into regional and local initiatives that proactively implement collaborative environmental management programs. One such program was recently initiated in northern Chile in recognition of the interconnection of Andean salars. Cooperative efforts between industry, governmental agencies and academic professionals have resulted in the implementation of simultaneous environmental monitoring of flora and fauna in the salars of northern Chile. This coordinated effort is leading to an improved understanding of the migratory patterns of South American fauna, as well as improved access to an expanded database for the multiple user groups associated with the Andean salars. The El Abra Mine is actively participating in these coordinated monitoring efforts.

Jan 1, 1999

By M. A. Rabah

This paper focuses on the separation and extraction of lead and zinc from Egyptian ore at the Eastern Desert close to Red Sea. The ore sample contains cerussite, galena, hemimorphite and other impurities. Experimental program includes flotationof galena using xanthate collector and cerussite using oleic acid as collector and sodium silicate to depress hemimorphite tailing. Galena, and hemi-morphite are converted to carbonate with sodium carbonate prior to metal extraction. Lead and zinc are extracted pyrometallurgically at 1050°C and750°C or electrochemically respectively. The overall performance of the applied method amounts to 99.2%. Extraction efficiency of lead and zinc amounts to 98% and 94.5 % respectively. A model assumed that galena and cerussite in the ore are partially oxidized and can be liberated by grinding. Oleic acid selectively reacts with cerussite in a multistep sequence. Preliminary cost estimate shows that the price of the products is competitive to their local market prices.

Jan 1, 2000

By J. Schenck

Goldcorp Inc. has mining operations and exploration projects throughout Canada, the United States, Mexico, Guatemala and Honduras; as well as partnerships in Argentina and the Dominican Republic. In rural areas of developing countries it is very common to have mining operations surrounded by diverse communities consisting of people with limited, or no formal education. This is fertile ground for anti-mining NGOs to cultivate. The limited educational backgrounds of the people, coupled with a company desire to maintain a low profile can lead to a problematic lack of trust between the local communities and the mining company. As part of its commitment to environmental stewardship and sustainable development, Goldcorp has implemented various programs to build trust at these operations, as well as incorporating this policy into any new projects prior to commencement of operations. This paper is intended to describe two initiatives that have shown positive results for both the communities and the Marlin Mine.

Jan 1, 2009

By C. Chamberlain

The mining industry continues to underpin the regional economy. Australia, benefiting from a weak currency, receives 27% of the total goods export value from non-energy mining lead by aluminium, iron ore, gold and nickel. Consolidation has eliminated CRA, Comalco, North, Savage, Acacia, Ashton, Great Central, Aberfoyle, Placer Pacific, Plutonic, Normandy and RGC leaving Rio Tinto, BHP-Billiton, WMC, MIM and, increasingly, the South African companies Anglo, Gold Fields and Harmony as dominant players. Exploration stagnates with expenditure dropping 40% in Australia and 80% in PNG from peak levels. Major new regional developments include Rio’s West Angles iron ore project, Newcrest’s Ridgeway gold-copper mine and Inco’s Goro nickel-cobalt project in New Caledonia.

Jan 1, 2002

By R. L. Derick

On a regular basis, mine personnel should obtain air samples directly from active underground areas as well as remotely from sealed locations. These samples provide mine officials with data relative to the makeup of the various atmospheres. Should conditions underground change, these results can provide a baseline that can assist officials in determining the extent of change. Relating the concentrations of individual gases to time, applying gases to equations, and examining their change over time are tools that have been successfully used to determine if a heating event exists and, if so, the extent of the emergency. These atmospheric status equations have either been developed for the mining industry or adapted from other industries. They serve as tools to assist personnel in determining the condition of underground mine atmospheres. As long as the problem area continues to be ventilated, certain gases, gas ratios, and equations can be used to determine if a fire exists, what type of material could be burning, and what quantity of coal is burning. Once the mine or the involved section has been temporarily sealed, gases, ratios, and gas-derived equations can assist personnel in determining how conditions within the sealed volume are changing over time. To alleviate potential explosions when fresh air is once again introduced into the sealed volume, equations and a diagram have been developed to predict the likelihood of an explosive atmosphere. Similarly, prior to commencing recovery of a mine or section, equations exist that can assist in determining if the fire will rekindle when air is reintroduced. This paper serves as an overview to remind and/or instruct readers about gas-sampling methodologies and gas analyses to assist in determining the status of underground atmospheres.

Jan 1, 2006

By G. Watson, S. Sawyer

A Method to Calculate Hydrodynamic Loads on Underground Bulkheads Bulkheads are structures built in openings in underground mines to impound water, preventing the water from entering the active mine workings. These structures not only have to be designed to withstand the static, hydraulic pressure, but also the dynamic or seismic pressure, which would be generated by an earthquake. Bulkheads can be considered underground dams. Unlike dams on the surface, bulkheads are often subjected to hydraulic heads that exceed the heights of the bulkheads. Theodor von Karman in 1933, and Westergaard earlier, developed the equation by which the hydrodynamic pressures on surface dams could be calculated. Civil engineering handbooks of today contain this equation. In this paper, using the methodology developed by von Karman and Westergaard, the authors have developed an equation by which the hydrodynamic forces on bulkheads could be calculated when the hydraulic head exceeds the height of the bulkhead.

Jan 1, 2007

By M. Fan

Dry coal separation technology has particular advantages in the applications in arid and cold regions, or low rank coal separation. The hazardous pollutants in low rank coals can not be efficiently removed by conventional wet coal separation processes because a considerable amount of porose and easily friable low rank coals suffer serious particle size degradation problems in water. In this paper, a novel dry coal separation method with a vibrated air-fluidized bed of magnetic fly ash and magnetite is put forward for dry coal beneficiation. The magnetic fly ash used in this study was derived from fly ash obtained as a byproduct of coal combustion. The vibration?s effect on the uniformity and stability of a magnetic fly ash air-fluidized bed was studied. The 6×0.5 mm dry coal separation results with a vibrated air-fluidized bed of magnetic fly ash and magnetite showed that the probable error E value of separation is 0.06-0.08 t/m3.

Jan 1, 2009

By R. W. Fedors, S. T. Green, F. T. Dodge, D. B. Walter

Spatial and temporal temperature variations in a high-level radioactive waste repository drift can give rise to moisture transport within the drift. Knowledge of this moisture transport may be important to assessing the potential for corrosion of all metallic components in the drift. The model presented here shows one approach to simulating evaporation, transport, and condensation of water in large underground openings using a framework based on computational fluid dynamics. Simulation results that explicitly model water and latent heat transport are presented.

Jan 1, 2004

By Maurus Seet Hong Hua

Introduction Coal has always been China&apos;s predominant energy resource. The country ranks among the three richest countries in coal reserves in the world, next to the US and the Soviet Union. According to China&apos;s Ministry of Coal Industry (MCI), coal accounted for about 72% of the total national energy consumption. Despite efforts to increase the output of oil and hydropower, coal is predicted to remain dominant on the energy scene by increasing its share to 77% by the turn of the century. To match the rapid growth in the agricultural and industrial sectors, MCI has targeted the coal industry to double coal output from 600 Mt/a (660 million stpy) in 1981 to 1.2 Gt/a (1.3 billion stpy) by the year 2000. How is this goal to be achieved? According to MCI, it will be accomplished by: • building new underground and surface mines with a total output of 400 Mt/a (440 million stpy); • increasing the output of existing state-controlled mines from the present 344 Mt/a (368 million stpy) to 400 Mt/a (440 million stpy); and • developing and increasing the output of small, local mines run by province, county, and production brigade from the present 276 Mt/a (304 million stpy) to 400 Mt/a (440 million stpy). Building new underground and surface mines New underground coal mines will be developed in areas where the coal industry has already made headway and infrastructures currently exist. This is to optimize hardpressed capital spending on investment. Ten existing coal production bases were selected in nine different provinces that met these requirements. The underground mines scheduled to be constructed in stages at he existing coal production bases will have a total output of 200 Mt/a (220 million stpy) by the end of the century. Regarding surface mines, four mines in the Inner Mongolia Autonomous Region and one in Shanxi province have been earmarked for construction during the same period. By the year 2000, these surface mines are expected to produce 200 Mt/a (220 million stpy). Foreign equipment, machinery, and surface mine stripping technology were all involved in different degrees in the development of the five new surface mines. Some have signed joint venture agreements. Occidental Petroleum Corp. is in a joint venture with China in developing Ping-shou&apos;s 15 Mt/a (16.5 million stpy) Antaibao No. 1 open-pit. The Shentou power station, situated nearby, is anticipated to consume 3.2 Mt/a (3.5 million stpy) of the coal it produces. Some is designated for export. Increasing output There are 554 state-controlled mines that have been in operation since before 1980. They produce 344 Mt/a (379 million stpy). To increase capacity, MCI has laid out some guidelines. • Coal prospecting near existing mines must be given top priority and intensified so that workable reserves can be increased. This would lengthen the mines&apos; useful life. • Many mines and slopes that were constructed during the 1950s are very small and densely populated. These small mines and slopes are generally very short along the strike. As a result, coal faces and levels require frequent

Jan 3, 1986

"It’s been 80 years since Charles Warman invented the iconic Warman slurry pump, a pump that revolutionized the mining industry and continues to push the boundaries of pump performance to this day.In honor of this legendary brand, Weir Minerals hosted an event at the end of May in Kalgoorlie, Western Australia. Throughout the evening, attendees relived Warman pumps’ history and gained an insight into some of the future innovations planned.“It was a privilege to share this special night with some of our key customers, past and present employees, and members of the Western Australian School of Mines,” said Ricardo Garib, divisional president of Weir Minerals. “Warman is one of our leading brands. It has truly shaped the mining industry over the past 80 years and is a product we are all very proud of. The Warman pump, invented to solve high wear issues in slurry pumping, created a thriving industrial business that is now the cornerstone of Weir Minerals with more than 8,000 people, and more than 150 manufacturing and service centers across the globe.”Always inventingCharles Warman invented the Warman slurry pump in Kalgoorlie in 1938. It was a hardwearing slurry pump that used replaceable liners and a replaceable impeller, something that had never been done before.“Charles Warman was a visionary and an innovator. The use of rubber lining in the pump was groundbreaking as it reduced total ownership costs, was safer to handle and offered extended wear life in many abrasive slurry applications. It is a great example of solving customer problems with material science, and is still taught in universities today,” said Marcus Lane, global product manager for centrifugal pumps at Weir Minerals.It was quickly adopted throughout the goldfields in Western Australia and by the 1950s, as customer demand rose, Warman expanded his business by opening offices in Sydney and Perth.During the 1960s the rapid growth of the business continued with manufacturing and sales outlets established around the world. The Warman Series ‘A’ pump was accepted and became a world leader in its field. Further work on the Warman AH pump resulted in the development of interchangeable metal and rubber wearing components."

Jan 9, 2018

By R. L. Guerguerian

Critical fasteners are described as they apply to the specification, manufacture, and assembly on large grinding mill bolted joints. The importance of adequate design methods, related joint diagrams and pivot analyses, and special emphasis on the quality of manufacturing and the tightening procedures in the field, are discussed; all in an effort to ensure high availability plant operation.

Jan 1, 2001

By J. M. Mutmansky, Y. J. Wang

The usual method employed to determine the direction of flow in a connecting airway in advance is to conduct a survey between the two existing nodes being connected by means of the new airway. It is then assumed that airflow will take place from the node with higher pressure to the node with lower pressure. The purpose of this paper is to examine this direction-of-flow problem -- using properties of the system characteristic curve for a two-terminal network -- and specify some conditions that ensure that flow will take from the higher-pressure node to the lower-pressure node. It is concluded that the only requirement is that all characteristic curves of fans in the network should be strictly decreasing. Five numerical examples illustrate some important properties of the direction-of-flow problem.

Jan 1, 1999

By J. S. Gardner, J. J. Zaluski

I. INTRODUCTION West Virginia has a long history of coal production.1 The state at one time led the nation in total coal production, while at the same time coal from West Virginia constituted one quarter of total U.S. coal production.2 In more recent years, however, West Virginia’s level of coal production has been reduced in comparison to that of other states due to the high relative cost of producing coal in the state.3 Another blow to the producers of coal in West Virginia is the action known as Bragg v. Robertson.4 In 1998 various individual plaintiffs, as well as a conservation group known as the West Virginia Highlands Conservancy, filed a civil action under a provision of the Surface Mining Control and Reclamation Act of 1977, Pub. L. No. 95-87, §522, 91 Stat. 445 (codified at 30 U.S.C. §§1201-1328) ("SMCRA" or the "Act") that allows declaratory and injunctive relief against state and federal officials for non-compliance with the Act.5 The plaintiffs generally claimed that the Director of the West Virginia Department of Environmental Protection ("WVDEP") had exhibited a pattern of violating mandatory non-discretionary duties under SMCRA and the West Virginia state regulatory program.6 These non-discretionary duties involved many areas of regulation, including water quality standards, disturbance of wetlands, hydrologic reclamation plans, Approximate Original Contour ("AOC") requirements and AOC variances, post-mining land uses, contemporaneous reclamation, and as explained later, the "buffer zone rule."7 In addition to these claims against WVDEP, the plaintiffs also alleged that certain individual members of the Army Corps of Engineers (the "Corps") had failed to carry out statutory duties under the Clean Water Act (the "CWA") and the National Environmental Policy Act ("NEPA").8 Generally, the complaint stated that the Corps did not have statutory authority under the CWA to regulate valley fills created for the purpose of the disposal of waste material, i.e., the overburden associated with mountain top mining.9 Alternatively, the plaintiffs claimed that even if the Corps could regulate valley fills, the Corps violated NEPA by issuing nationwide permits without required analysis. Finally, the plaintiffs asserted that the issuance of a nationwide permit for surface mining valley fills is unlawful.10

Jan 1, 2001

Introduction Some people say it is almost impossible to get mining permits in California. Some say the day of the lone mining entrepreneur is past. And some say you cannot make money mining gold where old-timers have already mined it, especially in Tertiary gravels. But a young mining operator and SME member, Tim Callaway, is proving these ideas wrong. Callaway&apos;s company, Brush Creek Mining and Development Inc., has the necessary permits for its Gardner&apos;s Point gold mine in Sierra County, CA. And, Callaway has secured funds for the 7.7 km&apos;/d (10,000 cypd) Tertiary gravel operation. The company&apos;s initial goal is to produce 373 to 466 kg/a (12,000 to 15,000 oz per year) of gold at Gardner&apos;s Point mine at a cost of less than $6.43/g ($200 per oz). Feasibility studies are currently being conducted to consider product levels up to the 1555 kg/a (50,000 oz per year) involving additional plants and infrastructure. While exploring for other hard-rock properties, the Brush Creek company already operates the Brush Creek lode gold mine. The mine sits high on a ridge south of Goodyear&apos;s Bar, which is located on the North Yuba river. It might be noted that the Brush Creek mine has been the subject of media stories recounting how a mine can operate with sensitivity to the environment. Gardner&apos;s Point project In 1983, Callaway negotiated with the Gardners Point Ltd. Partnership for control of the Gardner&apos;s Point property. The Partnership had been engaged for three years in securing permits, mapping and drilling, and test mining. The Partnership actually mined about 43.5 dam3 (57,000 cu yd) of gravel, which yielded 25.2 kg (810 oz) of free gold. Later, the Brush Creek company acquired ownership of the property. The company then began its own exploration and development program. As underground development proceeded at the Brush Creek mine, plans matured for a high-volume operation at Gardner&apos;s Point. Australian and English investors contacted Callaway. A joint venture was negotiated. The Australian owners became majority participants; the Brush Creek company, a minority participant and the operator. The Australian investors agreed to contribute $3.5 million (60%) to the Brush Creek Joint Ventures. The Brush Creek company will contribute its expertise as well as assets and liabilities valued at $2.3 million (40%). About $2 million has been allocated to the Gardner&apos;s Point project. Later, Brush Creek Mining and Development Inc. sold 50.4% of the company&apos;s common stock to English investors for $5.4 million. Callaway negotiated this private placement, which permits further exploration of projects being investigated. Geography and history The Gardner&apos;s Point mine is located in the northern Sierra Nevada of California, about 9.6 km (6 miles) east of the little town of La Porte in Plumas County. The mine lies high on a ridge above Slate Creek, which divides Plumas and Sierra Counties. La Porte is accessible from the Sacramento area by a winding, paved, two-lane highway. But the mine is reached only by two different unpaved county and Forest Service roads. Both roads include steep grades in and out of the Slate Creek canyon. Mine elevation is about 1.4 km (4600 ft) above sea level. The area is thus threatened by occasional heavy winter snows, though it

Jan 3, 1987

By E. Bauer, S. Moore

Technological advances in underground coal mining have led to a reduction in fatalities. This study demonstrated that the percentage of cumulative injuries remained largely unchanged across two decades of technological advances (1983-1984: 37%; 2003-2004: 33%). Furthermore, it was demonstrated that the average number of lost days due to cumulative injuries has increased (36±55 days and 62±82 days, respectively) which may have been due to the increased age of the work force or an increase in length of employment meaning that the mine workers injured in 2003-2004 had been exposed to ergonomic risk factors longer than those in 1983-1984. It is recommended that ergonomics processes be implemented as a means to systematically identify, prioritize, and resolve the root causes of these cumulative injuries.

Jan 1, 2007