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By Paul H. Johnson

The CH Leaching process is a new, more sophisticated, form of gold, silver, uranium and sulfide copper heap leaching wherein each layer of a multi-layered heap is divided into a number of independent cells, each of which are successively formed and leached in the top layer of the heap to their maximum economic recoveries, and then rinsed and sealed from further leaching. Triangular earth berms form the outside walls of the heap and a gridwork of rock-filled berms on top of the bottom pad form independent under- heap solution storage zones. The high degree of solution recirculation and staging that occurs in this process produces a relatively small volume of very rich pregnant solution. The cellular heap design and its mode of operation result in a uniform, intensive, long-term leach for all of the ore particles in the heap. Besides improved metal recoveries, the process appears to have several cost and operating advantages. In the CR2MR process, sulfuric acid and a soluble sulfide are added to a gold and/or silver pregnant leach liquor to precipitate most of the contained silver, mercury, copper, etc. as sulfides at a pH below 2.5. The other product of the reaction is solubilized HCN. Following a liquid-solid separation step, cyanide is regenerated in the supernatant solution by raising the pH to a level above 9.0. This process regenerates a portion of the cyanide used in the leaching step, removes contaminant ion species (silver, copper, mercury, etc.) from the leach solution and, in a subsequent step, recovers the gold in an enriched form. It is believed that substantial cost savings may be experienced by the use of this process in some gold and/or silver leach systems.

Jan 1, 1984

By Carl E. Brechtel, Edward D. Thimons

Providing adequate airflow to effectively dilute and remove diesel pollutants in large mine working headings is a little researched area. A simulated diesel mucking operation was carried out in the Exxon Colony Pilot Mine in Colorado to establish expected levels of diesel pollutants in dead-ended working headings. This heading was nominally 15.3 m (50-ft) wide by 9.2 m (30-ft) high. Two face ventilation systems were tested using sulfur hexafluoride tracer gas to represent the diesel pollutants. The results of these tests showed that conventional face ventilation systems operating at high flow rates could adequately ventilate diesel equipment in the 447-522 kw (600-700 hp) range, even in a dead heading 91.4 m (300 ft) in length.

Jan 1, 1987

By A. Mertzanis

The way and methods used for the surface mining of bauxite until the end of the twentieth century in the area of Ghiona, resulted in a significant burden to the natural environment, especially in the cases where it covered extended parts of forests and forest areas as well as important geomorphological formations. The impacts from the surface mining of bauxite which in fact constitute the object of this study relate mainly to the interruption of the natural continuity of the land relief and the alteration of the natural geomorphological activities and are due to: a) the alternating excavations with fronts of great heights, b) the depositions of large volumes of waste materials which originate from the revealing of the ore and c) the dense road network constructed in order to get access to the mine locations.

Jan 1, 2006

By J. G. Groppo

Froth flotation technique is an effective and efficient process for recovering of ultra-fine (minus 74 pm) clean coal. Economical dewatering of an ultra-fine clean coal product to a 20 percent level moisture will be an important step in successful implementation of the advanced cleaning processes. This study is a step in the Department of Energy's program to show that ultra-clean coal could be effectively dewatered to 20 percent or lower moisture using either conventional or advanced dewatering techniques. The main focus of the pilot plant study was on proof-of-concept testing of a dewatering technique for a fine clean coal product. The coal industry is reluctant to use the advanced fine coal recovery technology due to the non-availability of an economical dewatering process.

Jan 1, 1997

By Dana A. Echter

The Paso Diablo coal project is located in the Guasare Basin in the northwestern region of Venezuela near the border with Colombia. In 1987, Carbones del Guasare SA, a joint venture comprised of Carbozulia and A.A. Antilles Coal (an Arco and AgipCoal joint venture) was formed to develop the Paso Diablo coal reserves for world markets. Regional drilling has indicated a coal resource of more than 6 Gt (6.6 billion st). Further exploration has delineated the Paso Diablo deposit as an area particularly suited for cost-effective surface mining. The calculated economically minable reserves of this area (200 Mt or 220 million st) and the coal quality characteristics are based on extensive core drilling programs. Initial coal mining operations began in August of 1987 and the mine is presently producing at a rate of 1.5 Mt/a (1.65 million stpy). The coal is hauled about 85 km (53 miles) to a barge loading terminal at Santa Cruz de Mara using highway-type haul trucks. When the coal reaches the terminal, it is loaded into barges and then transloaded onto ocean-going vessels with barge mounted

Jan 1, 1990

By K. N. Han, P. B. Queneau, A. Stojsic, M. J. Collins, V. J. Ketcham, R. M. G. S. Berezowsky, W. D. Vardill

The bulk of the ore found in the Lihir Island deposit is refractory in nature, with the gold contained in auriferous pyrite. In support of an evaluation of the development of this deposit by Kennecott (a wholly owned subsidiary of RTZ) and Niugini Mining Ltd., testwork has been carried out at the Sherritt Research Centre to demonstrate the amenability of the Lihir ore to pressure oxidation pretreatment to liberate the refractory gold. The results of pilot plant treatment of the Lihir ore in a continuous circuit with a feed rate of between 10 and 30 kg/h ore are described. The integrated circuit comprised pressure oxidation, residue washing, and gold recovery from the washed residue by carbon in leach or carbon in pulp cyanide leaching. Significant factors affecting gold recovery included temperature and retention time in the pressure oxidation step, and the concentration of soluble chloride in the feed. Gold extraction from well washed ore, after oxidation at 210°C for 66 minutes in the autoclave, was typically between 94 and 96%, compared with less than 30% by direct cyanidation.

Jan 1, 1993

By DeVerle Harris

The enthusiasm with which individuals have participated in mineral exploration in the development of this country testifies to the fact that there was once a very real probability of making a worthwhile discovery. Over the years, the discovery and subsequent exploitation of the accessible ore deposits have made the finding of new deposits progressively more difficult. Present day mineral exploration has evolved from the lone prospector with the grubstaker behind him to a very costly and complex business, involving large sums of money and a staff of experts in the fields of exploration technology. Exploration today must be carried out on a large scale to be profitable. With the involvement of large amounts of capital, there has been a good deal of interest in methods of optimization of the allocation of the resources of a firm 'engaged in mineral exploration. As a step toward this, mathematical models have been formulated which are designed to quantify those variables of mineral exploration in such a manner that they can be integrated with all phases of the firms operations so as to optimize its profit objective or more simply, to make exploration more efficient and effective.

Jan 1, 1964

By Miroslaw M. Hajdasinski

A project's rate of return (ROR) [The list of all the acronyms used in his text is provided at its end.], be it an internal or external one, usually needs to be approximated. The success and efficiency of an approximation procedure depend on the quality of the initiating parameters such as bounds or seed values (guesses). Current approximation procedures commonly use bounds and guesses dictated by intuition rather then by mathematical consideration. The paper presents three ROR-bounding and six ROR-guessing approaches and examines their suitability on the examples of the typical project cash flow patterns.

Jan 1, 1996

By Andrew P. Gize

The analytical approaches used to solve a specific problem are dependent upon the information required, coupled with limitations imposed by available facilities, costs, and time. The organic matter associated with ore deposits has the potential to yield information for two problems. Information can be obtained to provide guidelines for prospecting, and, secondly, to solve genetic problems. A major potential of organic matter in providing prospecting guides lies in the high thermal sensitivity of organic matter in sediments which are metamorphosed at grades lower than greenschist facies. The organic matter can then be used to map thermal anomalies potentially associated with mineralization. The analytical approach is to determine the thermal maturity of the total organic matter, or of specific fractions, using techniques which are relatively quick and inexpensive. Consideration of genetic models (for example, reduction, complexing, involvement of oil field brines) generally requires more specific information than the overall thermal maturity of the organic matter, necessitating infor¬mation on molecular composition and structure. The facilities, time, and cost of this information are greater than for mapping thermal anomalies. The analytical techniques discussed include elemental analyses, spectroscopy (infra-red, visible and ultra-violet), Fourier Transform infra-red, nuclear magnetic resonance, extraction, pyrolysis techniques, chromatography and mass spectrometry.

Jan 1, 2013

By R. H. Grau

The National Institute for Occupational Safety and Health (NIOSH) has conducted research to improve the ventilation of large-opening mines. The research has demonstrated that the ventilation of large-opening mines improves significantly by including ventilation requirements in the mine planning process and implementing some practical techniques during mining. Planning the location of long pillars to reduce the number of crosscuts between intake airways and return airways, positioning auxiliary fans in their proper locations, and establishing ventilation stoppings with minimal leakage all significantly improve the ventilation of large-opening mines. Mine operators that adopt these techniques in the mine ventilation plan will reduce mineworkers? exposure to airborne contaminants.

Jan 1, 2008

By A. J. Basu

Computer assisted mine planning and design applications are routinely used by many Australian mining companies, However, the design process requires human expertise to recognize and evaluate the potential pitfalls. This paper introduces the application of a commercial optimization software (WHITTLE 4D) for strategic planning of an open pit mine in Western Australia. The authors present their experience in intelligent application of the optimization program while incorporating many technical and nontechnical obstacles. This paper provides some guidelines on how to apply the optimization software without loosing sight of practicalities. Moreover, this paper also shows how to build project evaluation guidelines for non-experts.

Jan 1, 1997

By Joseph Padgett

Of all the fossil fuels produced in the U. S., coal is by far the most abundant. U. S. reserves amount to an estimated 1.5 trillion tons, 2,500 times the 600 million tons produced in 1970. Although it would not be possible to recover all of this coal economically with current mining technology, a significant portion would be available given the proper circumstances. With existing technology, approximately one-eighth of these reserves is accessible, an amount which would last for several hundred years at the 1970 level of production. On the face of it, this substantial reserve should go a long way in meeting the Nation's energy needs. But coal offers special problems. As additional coal is mined and then burned, there are increased costs to the Nation's land, water, skies, and health. Hence, coal poses a dilemma because of its dual status as one of our most abundant domestic fuels and as one of our major sources of environmental degradation. Against the benefits that would be chalked up in the areas of national security, balance of trade, and economic well-being from the increased use of coal, we must enter on the debit side of the ledger the increased environmental cost. This paper reviews the use of U.S. fossil fuel, the drawbacks of coal as an energy source, the means being developed to overcome these drawbacks, and the background behind the present sulfur emission regulations relative to coal combustion. It also discusses in detail the Federal Environmental Protection Agency's (EPA's) current policies to ensure the continued use of coal as a major source of energy for fossil-fuel fired power plants.

Jan 1, 1973

By Russell Frith

A review of published literature reveals case histories whereby the entire periphery of a coal pillar has “burst” out as a single event during first workings, the associated energy and material release causing significant damage to adjacent roadways and any equipment/infrastructure located within said roadways. Such events are distinct from coal burst events during first workings such as that at the Austar Mine in 2014, or those linked to overburden bumps related to either horizontal stress-driven slip along major faults and/or thick, massive strata units in the overburden or floor of the coal seam.

By G. A. Kordosky

There are a number of reasons why the solvent extraction of molybdenum deserves attention: 1. The solvent extraction chemistry of molybdenum is interesting and complex, 2. The price of molybdenum is predicted to average about US$ 20.00 / pound in 2010 and, as China, India and other countries develop, the demand for specialty steels will increase putting long term demands on molybdenum supply, 3. Uranium ores often contain significant concentrations of molybdenum[1] and typically yellow cake will have a moly specification which when exceeded brings penalties, and 4. The valuable metal rhenium is a byproduct of molybdenum recovery circuits.

Jan 1, 2010

By Stephen Stone, Kerby Dobbs, G. Richard Whittecar, W. Lee Daniels, Zach Agioutantis, Tess Thompson

A common result of Environmental Impact Assessments associated with mining projects is the construction of new wetlands in areas disturbed by mining operations. Where appropriate, this mitigation may be considered an integral part of the mine reclamation process under the principles of sustainable development in the minerals industry. Wetbud is a new tool for estimating wetland water budgets using available weather data and site-specific topographic, soil and geohydrologic data, coupled with mass balance mathematics. Wetbud is primarily intended as a planning tool for use in the design of created wetlands, but it can also be applied to native wetlands or wetland restoration sites where the required input parameters can be specified. Wetbud can be run in its basic form where wetland topography, soil parameters and groundwater flux are simplified, or in the advanced form, where these parameters are included in a more complex approach via integration of the MODFLOW package, a free 3D program that was developed by the United States Geological Survey. Both versions can also include overbank flow hydrology sources and the advanced form can also model sloping and irregular topography. The program downloads weather data from the nearest applicable station and selects appropriate wet-normal-dry (W-N-D) years following a modest user data clean-up step. Wetbud also has the ability to utilize existing short-term (e.g. 6 to 9 months) groundwater data from an up-gradient well to simulate longer-term groundwater level inputs for the selected W-N-D years. In addition, Wetbud features a “Wizard” version that comes pre-loaded with 14 pre-selected weather data sets for all areas of Virginia that can develop a simple monthly water budget in less than 15 minutes – a feature that could be expanded anywhere geographically with historic weather data.

Jan 1, 2017

By Y. FUJII, E. CHANDA, J. KODAMA, D. FUKUDA, M. NISHIHARA, Y. NAKAYAMA, P. SINKALA

This paper describes a creep damage model that was proposed to clarify the rockburst mechanism for the Mufulira underground copper mine in Zambia. Cumulative rock damage was evaluated for the edge elements of each sidewall of the mining drives based on normal stresses by the 3-D displacement discontinuity method (DDM) (Crouch and Fairhurst, 1973). The rockburst occurrences were well hindcasted.

Jan 1, 2023

By Joe Keane

DOUG HALBE: The kickoff speaker, and my unanimous choice, is Joe Keane. Joe was born in Butte, Montana, and began his association with the mining industry as an under- ground miner at age 16. Currently he is president of KD Engineering and Metcon Research. He had it lucky when he went to school because there were only 44 elements in the periodic table, I understand. [laughter] Here's Joe. JOE KEANE: I'm doing this under protest. Maybe we can start the slides. Mr. Halbe gave me this topic, but I don't like it. I don't like Mr. Halbe either [laughter] because of the way he shanghaied me into this. He called me up on the phone and said this is what you're going to speak about: "Five Things I Never Want to See Again in Plant Design," and I said, "Huh!" Then I started getting stuff from SME about how to make a presentation. I have decided to change the title to "More Than Five Things I Never Want to See in Plant Design," since you can't have a completely negative speech; you have to have other topics. So we will have some other, not completely nonrelated, topics to sort of break the tension. I tried to find a joke to open with. I talked to Omar Mutati. All of his jokes were either about Bill Clinton, our beloved President, or they were too filthy to say in a mixed group. [laughter] So I decided to start this out with a profound statement. The pro- found statement is, "The meek shall inherit the earth, but not the mineral rights," [laughter] by J. Paul Getty. J. Paul Getty was one of my favorite guys because when a real obnoxious reporter asked him one day, "How can I become wealthy?" he said, "Drill for oil and find it."

Jan 1, 1998

By Elisabeth Tønnesen, Lloyd Tunbridge

"SUMMARY Injection grouting in rock around tunnels is used to reduce or stop water inflow. Little is known about the distribution of pressure within the rock mass during and after grouting. Instrumentation was developed to record pressure at the back of the packers inside the rock mass during injection grouting in order to improve our understanding of the process. Using this equipment measurements inside multiple injection holes during injection pumping have been made during several rounds of injection grouting in a tunnel. The data has been compared to the data recorded on the grout pumping rig and analysed to gain an understanding of the behaviour of grout injection process in the rock mass. The initial results are reported in this paper. INTRODUCTION Construction of a tunnel in soil or rock below the ground water table frequently results in the flow of ground water into the tunnel if the ground is permeable or fractures conductive. The injection of cement or chemical based grouts is frequently used during tunnel construction to reduce flow of water into a tunnel. Significant water flow into a tunnel is undesirable for several reasons: • there is a high cost in pumping out water over the lifetime of a tunnel; • drips and flows of water have to be diverted from the roadway or track; • where freezing conditions occur there is the possibility of ice build up and; • ground water levels may be changed possibly affecting surface water such as causing drainage of lakes and ponds, and changes in vegetation. Grout injection is most effectively done ahead of excavation to ensure that the grout penetrates the ground. Where heavy flows of water already occur into a tunnel the grout may be washed out before it sets. Normal practice in ground where water flows are encountered is to inject grout in a number of long holes ahead of the face with outer holes forming a ring around the proposed tunnel excavation – eventually forming a shield of grouted rock around the final tunnel, Figure 1. The holes may be sealed off a couple of metres into the rock with an expandable rubber plug around a pipe through which the grout can be injected, Figure 2. A one-way valve in the plug stops the grout from flowing back out of the hole when pumping stops and avoids grout flowing out through neighbouring holes. The rubber packer with a one-way valve permanently installed in the injection hole precludes the measurement of pressure down the hole when pumping is stopped."

Jan 1, 2016

By Dell H. Adams

Coal exploration may be defined as the acquisition of data necessary to define and acquire a block of coal which can be mined at a profit. Unlike ore minerals, coal resources are widespread and relatively abundant with supply exceeding demand in almost every case. Thus simple discovery of coal is generally not enough. The chemical and physical variability of individual coal seams, the capital intensive nature of coal mine development, and the changing patterns of utilization require that a multiphase, three-dimensional evaluation be made of each potential reserve. Factors which must be investigated include not only the quantity and quality of the coal but also the geologic, hydrologic, and engineering characteristics of the seam and its surrounding strata. Acquisition of property to provide a secure base for exploration and mine development is equal in importance to the geologic and engineering programs. The successful development of a coal reserve requires that control of coal and, in the case of a strip mine, the surface be in the form of contiguous blocks of sufficient size to support mining.

Jan 1, 1981

By Z. D. Hora, W. N. Hamilton

Introduction Some unique opportunities exist for industrial minerals in British Columbia and Alberta. The region's diversified geology, particularly in British Columbia, offers favorable environments for a rich variety of mineral resources. Many minerals have been produced for years. For some, however, the level of production is far less than the potential. Others have had production in the past, but are not currently produced. Still others are known to exist and may have been actively prospected. But they are not yet developed. In addition, a number of speculative possibilities have recently come to light. The potential significance is not fully confirmed, but is suggested in showings in favorable geologic settings. Location and geography British Columbia and Alberta are the westernmost provinces in Canada (Fig. 1). The region overlaps two major physiographic divisions of the country, the Cordillera and the Interior Plains. It also takes in a small segment of the Canadian Shield on the east. The entire territory is greater than 1.6 Mkm2 (618,000 sq miles). Most of British Columbia lies within the Cordillera, a mountainous belt some 800 km (500 miles) wide. The belt is made up of three main physiographic components, the Eastern, Interior, and Western subdivisions. The Eastern subdivision embraces the rugged, linear ranges of the Rocky Mountains, elevations between 2600 and 3300 m (8530 and 10,800 ft). They form a 100-km (62-mile) wide band straddling the BC-Alberta border and extending northwest across northern British Columbia. The Interior subdivision includes several ancient mountain ranges but is dominated by an intermountane plateau area of low relief (average elevation 1200 m or 3900 ft). The Western subdivision is dominated by the Coast Mountains (elevations between 1800 and 4000 m or 5900 and 13,123 ft). These form a band about 175 km (110 miles) wide into which are sculptured the spectacular fiords of the BC coastline. Alberta lies largely within the Interior Plains, a prairie region of low to moderate relief (elevations between 200 and 1200 m or 650 and 3940 ft) formed of nearly horizontal bedrock strata. The Plains surface rises gradually to the southwest toward the deformed belt of the Rocky Mountains, where the bedrock strata are upturned, folded, and faulted. To the east, the Plains merge with the Canadian Shield, which exposes the Precambrian crystalline basement of western Canada. The total population of the BC-Alberta region is about five million people. Minerals, forestry, and agriculture are the primary industries here. It has well developed infrastructures to service these industries. British Columbia is third among the Canadian provinces in metal mining - $1.1 billion in 1985 - and first in forest products. It is also second in hydro-electric power development. Alberta leads all provinces in total mineral production, largely due to its extensively developed petroleum and natural gas resources - $26.2 billion in 1985.

Jan 12, 1987