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A portable electronic instrument was developed which will measure change of longitudinal wave velocity with change of uniaxial stress in rock columns. The instrument is a solid-state device powered by nickel-cadmium batteries. It uses a probe of two piezo-electric crystals spaced inches apart to send and receive a pulse through a stressed rock. A one-inch cathode ray oscilloscope visually displays the longitudinal wave. A reference chart is used to find the stress. Laboratory results have indicated that the average stress on a sandstone column can be found to within 35 psi. The feasibility of using this instrument to determine stresses in mine pillars is to be studied. The instrument may be used to investigate physical properties of rock.

Jan 1, 1970

By R. Latifovic

Assessment of the possible impact of existing and future mining projects located in remote areas may be difficult and costly. This may have an adverse effect on the process of issuing mine permits and development of new mines. A remote sensing based land cover change assessment methodology presented in this paper is a promising avenue to render this process more meaningful, precise and affordable. It has been applied to a case study of the Oil Sands Mining Development in the north-east of the Canadian province of Alberta. Recently, the Athabasca Oil Sands Region (AOSR) is a place of unprecedented growth of open-pit mining operations. This study was focused on the primary impact onto the landscape and vegetation resulting from exploration and, mining development. This impact was assessed using an information extraction method applied to two LANDSAT scenes. The analysis based on derived land cover maps shows a 8.64% decrease of natural vegetation in the study area (715,094 ha) in 2001 relative to 1992. It is demonstrated that the methodology presented here provides reliable results and is fully applicable for the assessment of the environmental impact of large scale mining operations.

Jan 1, 2006

By G. Whitney, J. Steiner

Introduction The Summitville Mine located in southwestern Colorado is an example of the potential impact that natural weathering and mining activities can have on environmental quality. Acid rock drainage and metals leaching from active and historic mine districts are a major environmental problem facing the mining industry today. Sulfide ore exposed naturally or during mining operations has the potential to produce leachates that contain high concentrations of dissolved metals. These leachates can affect the quality of plant and animal health in surface water used for agriculture, recreation and human consumption. Pintail Systems has developed biological processes for detoxification of cyanide in heap-leached spent ore and process solutions. During application of spent ore cyanide bio-detox processes we have also observed a substantial reduction in many of the leachable metals in biotreatment solutions. These field observations of soluble metal reduction led us to propose that metal bio-mineralization should be a secondary treatment goal of spent ore detox in Focused Feasibility Studies (FFS) for the Summitville Mine. In the FFS (described in a companion paper) for Summitville, spent ore from the heap leach pile (HLP) was loaded into PVC test columns (six inch X ten foot) and was leached with bacteria/nutrient solutions. Two treatment designs were studied: a standard percolation leach (aerobic) and a saturated leach design where the ore was saturated with the heap leach solution to which bacteria and nutrients were applied in a continuous biotreat leach. The bacteria for all column treatment tests were isolated from the spent ore at depth through the Heap Leach Pile (HLP) in the saturated and unsaturated zones. Bacteria isolated from the heap material were tested for cyanide oxidation capacity and were submitted to a bioaugmentation program to improve reaction kinetics and metals tolerance. The final treatment population consisted of several distinct species including aerobic heterotrophs, facultative anaerobes and sulfate-reducing bacteria. The remineralization of soluble metals was observed through a decrease in copper in column leachate solutions and the formation of observable mineral products on ore surfaces in the columns. Several of the tests were run in clear PVC columns to facilitate observation of mineral formation. The column ore contents were photographed before, during and after the biotreatment process which ranged from 10 to 20 days for each test column. Ores were collected from each column after the treatment was complete and were submitted for SEM and TEM study at two laboratories - the USGS SEM Laboratory in Denver, Colorado and the City College of New York SEM laboratory. Treatment Process Description Numerous species of bacteria, fungi and yeasts are capable of accumulating many times their weight in soluble metals. Both living and dead biomass are effective in removing soluble metals from waste streams containing gold, silver, chromium, cadmium, copper, lead, zinc, cobalt and others. Soluble metals may also be immobilized in soils by natural or engineered biomineralization reactions. Several commercial processes using biological reactions are being applied on an industrial scale for metal remediation. Bacteria found in natural and extreme environments have developed a wide variety of metabolic functions to adapt to these environments. These natural microbial functions contribute to global mineral cycling that continuously forms, transforms and degrades minerals and metals in the environment. Biomineralization is described as a surface process associated with microorganism cell walls where the remineralization occurs. The biogeochemical activities initiated by microorganisms in ores, soils, surface and groundwater environments can dominate the formation and transformation of those mineral environments.

Jan 1, 1995

By R. V. Ramani, J. Qin

During the mining process, the in-situ material is broken into different size ranges, from very large pieces to very fine particles. Some of the fine particles become airborne. In underground coal mining, airborne respirable dust is associated with health and safety of the miners. The amount and size distributions of airborne dust are important parameters to effective dust control measures. The design of underground mine experiments, including sampling procedures and sample analyses methods to determine these parameters are presented in this paper. A total of fifteen continuous miner cuts were sampled. The amount of dust generated during the cutting process and the relationship between total and respirable airborne dust concentrations and amounts are examined. The amount of respirable dust airborne is on the average only 0.016% of the respirable dust generated. On the average, 61% of the total airborne dust measured is in the respirable size range. The amount of respirable airborne is on the average 36% of the respirable size fraction in the total airborne dust. For equal proportion of rock and coal material cut, rock contributes about twice as much fines (=0.22 mm) as coal. Additional fundamental research is necessary to further the understanding of the airborne propensity of respirable dusts in mine atmospheres.

Jan 1, 1989

The results of studies to ameliorate acid mine drainage by retarding the rate of oxidation of pyrite at source are discussed. In the transpassive region, pyrite oxidizes by reactive dissolution, mass transfer through the product layer and diffusion in the bulk solution. One can decrease the rate of pyrite oxidation by inhibiting either oxidation reactions or cathodic reactions. It is demonstrated in this study that some surface active reagents extend the passive region by affecting both the anodic and cathodic processes. The extension to higher potentials occurs by inhibition of the anodic dissolution process whereas to lower cathodic potentials through decrease in the rate of reduction of molecular oxygen and/or ferric ions. To retard the oxidation of pyrite by ferric ions, which is considered to be the dominant oxidant under conditions of acid mine drainage, it would be necessary to restrict mass transfer or promote complexation of ferric ions at the surface. Imidazoline based reagents were found to be most effective in meeting this goal.

Jan 1, 1994

By T. Gouri Charan, G. V. Rao

A spherical agglomeration process for the separation of scheelite fines of less than 30 µm in very low concentration of 0.04% WO3 in a binary mixture with quartz fines of less than 30 pm has been described. A concentrate containing 14% WO, with more than 90% recoveries could be achieved by means of anionic sodium sulfo succinate collector at pH 3.5 and also with commonly used anionic sodium oleate at pH 10.5 as per the conceptual flowsheet suggested. Such a process is envisaged as commercial potential for the recovery of fine-grained scheelite present in the tailings of gold plants as found in India.

Jan 1, 1991

Gold heap leach operations often process low grade ores with little margin for cost increases. The advantage of heap leach operations is the considerable savings in both capital and operating costs. This paper looks at an alternative pH modifier to lime in the heap leach process, namely bauxite waste mud or red mud. The red mud can contain trace amounts of gold and was found to be an excellent source of slow release sodium hydroxide for long-term pH modification. Column cyanide leaches showed that 25 kgt-1 of red mud provided a higher pH and longer pH modification than 0.25 kgt-1 of lime. Contaminants leached from the red mud hampered the adsorption of the aurocyanide complex onto activated carbon.

Jan 1, 1993

By L. C. Bartel

Geologic features such as structure (faults, folds, fractures, etc.), water bearing zones, aquifers, pemeability variations, and porosity variations are important for mine planning and in situ energy recovery processes. Features important for planning a mine will be important for planning the recovery of energy by in situ processes. Various geophysical techniques might be used to obtain the necessary geologic information. In this paper, case histories will be discussed of the use of electromagnetic geophysical surveys at a potential underground coal gasification site and a potential tar sand oil recovery site to obtain pertinent geologic information. Results show that the controlled source audio- frequency magnetotelluric technique shows promise for mapping faults and natural fracture systems when there is a sufficient resistivity contrast.

Jan 1, 1982

By Charles O. Frush

This paper presents a summary of the current employment practices with respect to recent graduates in Mining Engineering, as observed at the Colorado school of Mines. Because our experience is limited to our own group of students it prob¬ably does not correspond exactly to that experienced at other mining schools, but because the Colorado School of Mines graduates approximately 15 per cent of the men in this field our experience is probably representative. We have chosen to limit the information presented here to that pertaining to the period since July 1, 1960. This corresponds to the experience with the class of 1961 and to the experience of the class of 1962 up to the end of the first semester of the senior year. There were 36 mining engineering degrees given in 1961 In a class numbering 43 senior. We expect to give 30 first degrees in 1962 in a class numbering 44 seniors.

Jan 1, 1962

By Juan C. Diaz, Juan P. Carmona, Manuel Z. Salgado, Oscar J. Restrepo

The “Teaching Kids” project is an educational initiative for young people and children from elementary schools. It is carried out by Mining, Geological, and Environmental Engineering students from the SME Student Chapter of the Universidad Nacional de Colombia, Medellin. The primary purpose of the Teaching Kids project is to share knowledge about geosciences and mineral resources in a didactic and attractive way, emphasizing the importance of identifying the use of minerals in daily life and responsible and sustainable mining in our society. Furthermore, this project aims to promote the importance of pursuing geoscience majors in the new generations and improve the mining industry’s public perception. Different methodologies related to early childhood education are implemented, such as gamification, in which the dynamics of games are adapted during the development of workshops to teach and learn in an active and motivated environment. Furthermore, the Montessori Method is used. It implements textbooks, sensory mineral boxes, and presentations to allow learning through experimentation itself (Montessori 2003). The implementation of this methodology has been successful; it has shown high engagement, participation, and retention of the basic concept of geoscience and mining.

Feb 1, 2025

By Cleland N. Conwell

Intermittent coal mining has been conducted in Alaska for over a century. The first report of coal in Alaska was by the Veechy expedition of 1826 and 1827. Whaling ships used coal from Corwin Bluff near Cape Beaufort during the early and latter parts of the 19th century. The first coal mine in Alaska -- and probably the oldest in the Pacific coast of North America -- was opened by the Russians at Port Graham on the southwest tip of the Kenai Peninsula. The mine was operated from 1855 until 1867 when the United States took possession of Alaska. From 1880 to 1915 coal mining was carried on intermittently at several localities including Unga Island, Herendeen Bay, Chignik Bay, Kachemak Bay, and several points along the Yukon River. Small coal mines along the Yukon River provided fuel for the river steamers traveling from St. Michaels to Whitehorse. The area of sustained coal production began with the completion of the Alaskan Railroad from Anchorage to the Matanuska coal field in 1916 and to the Nenana field in 1918. Coal production continued to increase until 1953, at which time the oil and gas fields in Cook Inlet were developed. Oil and gas eventually replaced- the Matanuska coal as a means of providing heat and power. The military in the Anchorage area shifted from coal to oil in 1967 causing a decrease in production. The increased demand for electric power in the Fairbanks area offset the decline and coal production started to increase. In 1969-1970 the Golden Valley Electric Association constructed a mine-mouth power plant 70 miles southwest of Fairbanks near Healy and a power line to Fairbanks. LOCATION OF COALS IN ALASKA Coals are found in all geographical subdivisions of Alaska. Coal in Alaska ranges in age from Carboniferous to Tertiary, and grade from lignite through anthracite. Figure 1 shows the locations of Alaskan coal fields. The only fields that have been developed extensively are the Matanuska and Nenana. Figure 2

Jan 1, 1972

By F. X. Ferney

The centrifuge which will be reviewed in this dis¬cussion is the continuous solid bowl typo. As there are presently approximately 2000 of these units operating in our country, and about 200 of these in use in the coal industry, I expect that most of you are acquainted with its operating principle. How¬ever, for those who are not familiar with the machine a brief introduction is in order. The continuous solid bowl centrifuge was first successfully marketed, worldwide by the Bird machine Company in 1934. The successful development of this unit was based primarily on the invention of a drive mechanism to properly control the differential speed between the two rotating elements. This centrifuge was introduced into the coal industry immediately following the second World War. Today there are five or six additional firms' selling this machine in our country, and approximately twenty others in Europe, England and Japan.

Jan 1, 1965

By S. C. Termes

As part of an effort to provide basic data on the fundamental scientific and engineering principles of minerals beneficiation, the Bureau of Mines is conducting research on the flocculation of mineral fines. This paper presents results of studies using crosslinked starches containing carboxyl, diethanolamine, iminodiacetic acid, and xanthate groups to flocculate hematite, goethite, chromite, manganrte, pyrolusite, cuprite, and cassiterite fines. The carboxyl and xanthate derivatives flocculated all minerals except cassiterite; the latter was flocculated by only the diethanolamine derivative. The iminodiacetic acid derivative flocculated hematite, goethite, chromite, cuprite, and pryolusite fines. Zeta potential measurements were made to help define the reaction mechanism responsible for flocculation. These measurements indicate that electrostatic attraction probably is not involved, except possibly in the case of the diethano lamine derivative. The separation of hematite from quartz by selective flocculation with chelating cross- linked starches under two pH conditions and with two dispersing agents is described. Best recoveries and grades were found when either the carboxyl or xanthate derivatives was added at the natural pH of the pulp in the absence of a dupersing agent.

Jan 1, 1983

By F. C. Appleyard

A couple of miles southwest of the town of Saltville in the western tip of Virginia is a little village called Plasterco. Gypsum has been produced in this area since about the year 1815, being originally found as small outcrops at the surface. Production in the early days was very small, and the use of the mineral was limited to that of "land plaster" or ground gypsum which was spread on the land to sweeten the soil. In the late 1800's, a small calcining plant was constructed and the production of gypsum plaster began. About this same time, the surface rock was depleted and it became necessary to begin underground mining operations in order to maintain a continuous supply of raw material. The United States Gypsum Company became interested in this property in 1909, and has operated there ever since, having enlarged the calcining mill and built a plant for the manufacture of gypsum wall-board in the middle 1920's. Production of gypsum continues from underground' mining operations, and the present mine at Plasterco is now about 1,000 feet below the surface, making it the deepest gypsum mine' in the world.

Jan 1, 1965

By Wayne R. Hopkins

Southern Arizona has one of the world's principal concentrations of copper ore bodies. Twenty miles south of Tucson, close to the Mexican border at Sahuarita in Pima County, is the Twin Buttes mine. In mid-1973, the Anaconda Company and American Metals Climax Incorporated (AMAX) established a 50-50 partnership to operate and expand the Twin Buttes property. Anamax Mining Company was established as the operating company for this joint venture. The production from the Twin Buttes mine is shared between the two partners who market independently. A major expansion of the Twin Buttes operation has included an accelerated stripping programrne for the pit, an expansion of the sulphide concentrator, the construction of an oxide leach plant and a 57 MW diesel generating power station. Part of this major expansion, the large tonnage oxide processing plant was brought on stream in 1975 and is now close to design capacity. The "mine to market gap" has been closed by producing high-purity copper cathodes at the mine site from oxide ore reserves. By using a hydrometallurgical process route, copper production is possible with negligible effects on the environment.

Jan 1, 1976

By V. Rastogi

Acid rock drainage is the result of exposure of sulfidic materials, such as pyrites and sulfidic ores, to air and water. The oxidation of these sulfides is catalyzed by more than a million times by the bacteria Thiobacillus jerrooxidans and close families. Inhibition of these bacteria can mitigate 98% or more of the acid loading generated. This can be achieved by the use of certain surfactants that are selectively bactericidal to the lithotropic acidophilic bacteria. Bactericides are used in two ways. As periodic or continuous treatments for prevention of acidification of material actively handled and moved, and in controlled release form for reclamation where treatment sets up a change in site microbiology to replace Thiobacillus jerrooxidans with heterotrophic bacteria and creates a stable site without need for further treatments. Use of bactericides begins with laboratory testing of the site material to qualify the site for bactericide treatment and dosage determination. Site specific treatments are designed for active sites and reclamation. Once acid production is controlled, solubilization of metals is correspondingly reduced. Results and economics of use from active and reclamation sites are presented.

Jan 1, 1995

By R. Fedors, T. Ghezzehei, D. Or

The phenomena of dripping into cavities (e.g., tunnels and drifts) within an unsaturated fractured porous medium under ventilated conditions was studied to improve estimates of dripping rates, drop sizes and the chemical composition of droplets that could affect the integrity of high-level nuclear waste packages placed in drifts. The sensitivity of dripping rates and water chemistry to ventilation was analyzed at various flow rates using analytical expressions linking flow on fracture surfaces to drop formation and evaporation. The model was tested using laboratory experiments involving machined aluminum slabs designed to represent a simplified morphology of a fracture face intersecting a cavity and using natural fracture surfaces from a welded tuff Comparison with ten years of data on dripping in natural caves showed good agreement with model predictions. In particular, for low dripping rates, evaporation due to ventilation leads to larger drop sizes and alters drop chemistry by increasing the concentration of solutes in the drop relative to that in the water flowing on the fracture face.

Jan 1, 2002

The National Mining Association’s (NMA)MINExpo International ’96 is shaping up to be the organization’s largest. About 30,000 mining industry business and technical professionals are expected to descend on Las Vegas, NV Sept. 9-12 to take part in the 25 technical sessions and visit the more than 900 exhibitors who will be showing off their products and services. MINExpo will be the largest mining equipment and services exposition in the United States this year. Exhibits at MINExpo will fill the Las Vegas Convention Center, parking lots and part of the Hilton Center, located next door to the convention center. NMA estimates that this year’s show will cover more than 46,450m2 (500,000 sq ft) of exhibit space. Some of the exhibits on display will include haultrucks, hydraulic shovels and excavators, conveyors, continuous miners and tunneling machines. In addition, an array of computer equipment and software will be demonstrated. A new feature this year will be a helicopter pavilion, located in the Hilton Center. Helicopters and fixed-wing aircraft have become indispensable to many remote mining operations. NMA said that at least one full-size helicopter will be on display.

Jan 1, 1996

By Jim Salley, Mohammad Saleem, Indra Banerjee, Kevin Sapp

"On underground construction projects, effective Quality Management is essential for ensuring facility durability, life cycle performance and low maintainability. Furthermore, follow on contracts also rely on an effective quality management system for interface congruency. An effective Quality Management System (QMS) is also essential in mitigating risks and meeting schedule and budget performance objectives. For the past 15 years Central Puget Sound Regional Transit Authority’s Link Light Rail extension has successfully completed over 10 miles of twin bore tunneling and associated underground features including cross passages, deep sump structures and shafts. After the completion of each segment, lessons learned have successfully been implemented to improve the quality of delivered projects. This paper presents the Sound Transit QMS with regard to a number of project elements of tunnel construction projects, with specific focus on quality performance of slurry wall construction, TBM tunnel excavation assessment, segment production and segmental lining installation, and other associated construction features. A collaborated total QMS will be presented in this paper that will serve as a guide for successful implementation of Quality Assurance and Quality Control processes. INTRODUCTION Implementation of a robust Quality Management System reduces defects, errors and omissions, identifies and addresses nonconformance in a timely manner and increases stakeholder confidence in the project. In fact and effective QMS helps ensure that optimal project outcomes are realized both in terms of project delivery and life cycle performance. The two key components of QMS are quality control and quality assurance. Quality Control (QC) is the procedure implemented to achieve a certain level of quality and ensure that products, processes and services meet specific requirements. Quality Assurance (QA) activities are carried out to evaluate the effectiveness of the quality control measures and ensure that the QC process is working. A team obligation that recognizes that quality is built into every aspect of a project is the basic concept of a successful QMS."

Jan 1, 2016

By Frederik P. Agterberg

Mineral exploration consists of the acquisition of data and their interpretation to ascertain the presence or absence of uncertain events. In general, the amount of uncertainty decreases during exploration when targets become increasingly well defined. Decisions on further exploration and whether or not mining should be commenced are based on new information using both objective facts and subjective reasoning. Computers play an important role during all stages of exploration. Three recent books (References 1-3) on decision-making in exploration and mineral-resources evaluation provide additional background supplementing the papers in this volume and articles in scientific journals or other conference proceedings (e.g., References 4 and 5) dealing with the subject. Other new developments to be considered are that microcomputers are becoming increasingly important in the earth sciences (Reference 6), and so are applications of artificial intelligence (Reference 7). Microcomputer- based technology allows rapid communication between field parties and main office. Expert systems are becoming increasingly sophisticated aids for mineral exploration an can now contain objective rules based on statistical theory (Reference 8).

Jan 1, 1989