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By Russell G. Slayback

Feasibility investigations for prospective gold mines too often neglect to consider ground water. Simple observations and tests during drilling exploration can provide useful data on probable water conditions. As the prospect becomes more serious, more detailed investigation of ground water and dewatering needs may be warranted. Ignoring ground-water conditions can lead to costly mistakes.

Jan 1, 1987

By Raymond W. Henn

The 32nd annual short course ?Grouting Fundamentals and Current Practice? was held at the Colorado School of Mines, June 13-17, 2011. The field demonstration portion of the course was conducted June 16 at Baski Inc.?s yard in Denver, CO. The full-scale field demonstration presents many types of drilling and grouting equipment in operation as well as numerous grouting methods per-formed under various field conditions. As part of the field demonstration, the class was shown the proportioning, mixing, testing and injection of various cement grout mixes into sand columns under controlled and recorded conditions. These sand column demonstrations have been conducted under controlled and measured conditions each year since 1999 as part of the short course. The sand column demonstrations were conducted prior to 1999, but with less quality control and minimal record keeping of the proportioning, mixing, testing, injection pressures and the final permeation results.

Jan 1, 2011

By E. H. Cho

An acid mine drainage sludge sample containing 3.6% Mn, 0.18% Ni, 0.15% Co and 0.39% Zn was obtained from the central part of West Virginia and leached with sulfuric acid at pH 3 and at room temperature. Air was bubbled through the leach solution to precipitate the iron content from the solution at pH 4.5. The leach solution contained 258ppm Zn, 105ppm Ni, 90ppm Co and 2050ppm Mn. Three distinctive solvent extraction studies were performed to selectively extract these metal ions in a sequential operation with DEHPA, Cyanex 272, and then Lix 84. The AIO ratio was 1 and the extractants were diluted 10 times with kerosene. A study of solvent extraction with DEHPA showed that Zn could be extracted without Ni or Co up to pH 2.75. A pH of 2.75 is considered to be the optimum pH to maximize the selective separation of Zn from Mn. The separation factor of Co over manganese suggests that the two metal ions be extracted together by Cyanex 272. The separation factor of Co over Ni indicates that these two metal ions can be separated most effectively around pH 5.3. Also, Ni can be effectively extracted by Lix 84 above pH 5.5.

Jan 1, 1993

By J. Searls

The potash review arrived too late to appear in the June issue. Potash is a general term that includes several water soluble potassium salts: potassium chloride (muriate of potash), potassium sulfate (sulfate of potash), potassium magnesium sulfate (sulfate of potash-magnesia), potassium nitrate (niter) and sometimes potassium carbonate. Potassium carbonate was the original potash when it was leached from wood ashes and dried in large, cast iron pots to black-to-gray crystals (ash) to form "pot ash." "Pearlash" was potash roasted to white crystals. In modern terminology, the great preponderance of "potash" is the mined forms. It is estimated that 95% of the potash mined around the world is used as fertilizer. In 1840, Justus von Liebig demonstrated to the scientific community the importance of potassium to the growth of plants. But there was no low-priced source of potash available at that time. In the winter of 1851-1852, minable potash was discovered near Stassfurt,

Jan 1, 1991

By W. J. Karwoski

A ground-support system for grizzly and haulage drifts was tested in Magma Copper Co.'s San Manuel mine. Eight two-piece, wide- flange steel sets were erected in a ventilation drift on the 2315 grizzly level. The sets were lagged with three different materials and back- packed with pea gravel and sand. The pillar on either side of the drift support system was instrumented with stressmeters and rock-bolt load cells, the backfill with pressure cells, and the steel sets with load cells. Results indicate a better survival rate than with typical monolithic concrete.

Jan 1, 1979

By J. Fuller, L. Marsden

Windborne dust from alkaline salt flats and mining-related tailings ponds is especially prone to threaten applicable ambient air quality standards. Sodium carbonate crystals, typically present, weather to an exceedingly fine, non-cohesive dust, causing air quality problems for miles downwind. Recently developed specialized polymers react with alkaline dust to form sturdy, wind-resistant crusts with good longevity. An on-going demonstration project at a major trona facility has developed techniques for cost-effective application of these polymers over large areas of soft tailings or sediments in a wide variety of situations. Recently treated areas on the order of 80 acres show effective suppression of dust.

Jan 1, 2004

By John N. Murphy

In fiscal 1996, the US Congress directed that the US Bureau of Mines (USBM) be closed. Certain functions were reassigned to other agencies. The remaining employees were separated and the unoccupied sites were decommissioned. As a result, 12 locations were closed and about 1,200 employees were terminated in March 1996. About 600 employees at five locations were reassigned to other federal agencies. This article provides a summary of the continuing functions, the agencies involved and the points of contact for each continuing function. The functions that were discontinued are also identified. The functions that have been maintained and transferred to other agencies are: ? Portions of USBM's Mineral Information and Analysis program formerly conducted in Washington, DC and Denver, CO were assigned to the US Geological Survey (USGS). ? The Mineral Land Assessment program in Alaska (Anchorage and Juneau) was transferred to the US Bureau of Land Management (BLM). ? The Health and Safety Research program in Pittsburgh, PA and Spokane, WA was reassigned on an interim basis to the US Department of Energy (DOE). In fiscal year 1997, it was permanently assigned to the National Institute for Occupational Safety and Health (NIOSH). NIOSH is part of the Centers for Disease Control and Prevention within the US Department of Health and Human Services. ? Environmental Research at Pittsburgh, PA was assigned to DOE. ? Materials Research at Albany, OR was assigned to DOE. ? The helium program was assigned to BLM, where it will be managed pending privatization. ? Coal and noncoal mine maps were transferred to the Office of Surface Mining Reclamation and Enforcement (OSMRE). The following locations were closed: ? Research centers in Denver, CO; Minneapolis, MN; Reno, NV; Rolla, MO; Salt Lake City, UT and Tuscaloosa, AL. ? Field operations centers in Denver, CO and Spokane, WA. ? Washington, DC headquarters office. To provide a concise picture of all of the affected functions, the following is a synopsis of the USBM program functions and facilities immediately before the closure. There were two principal programs: information and analysis, and research.

Jan 1, 1997

By Jack S. McPartland, Gene E. McClelland

It is advisable, for any heap leach project, to develop an historical metallurgical data base to predict production heap performance before ore is mined and placed onto the heap. A data base would include results from: interval assays, cyanide solubility tests, and bottle roll tests on exploration drill cuttings samples; and those results plus column leach test data on diamond drill core or bulk ore composites. Subsequent larger scale heap leach test data can then be compared to the historical data base, to blast hole composite data during mining, and eventually to production data. This paper does not discuss metallurgical comparisons between assays, cyanide solubility tests, and bottle roll tests on exploration drill cuttings samples, but does discuss metallurgical comparisons from bottle roll tests, laboratory scale column leach tests, and pilot scale heap leach tests on core and bulk ore samples with operating data for three U.S. commercially producing heap leach operations. Provided that representative core or bulk samples are used for evaluation, heap leach test results accurately predict or understate the success of the commercial operation and remove most of the uncertainty from the investment decision.

Jan 1, 1990

By J. D. Miller

Characterization of feed material with respect to expected concentrate grade and recovery is fundamental to the design of improved separation efficiencies and to achieve sustainable development in the utilization of our mineral resources. An important reference point for this characterization is the liberation-limited grade/recovery curve which represents the perfect separation, the best separation which can be achieved for a given feed material limited only by the extent of liberation. Now, liberation-limited grade/recovery curves can be determined based on 3D mineral liberation analysis of feed material. Thus, actual separation efficiencies can be compared to what might be expected for a perfect separation limited only by the extent of liberation. It is shown that 3D mineral liberation analysis based on X-ray micro CT (XMCT) is preferred to 2D section analysis which overestimates the extent of liberation. By way of example, procedures and experimental results are presented and discussed for feed material in the case of phosphate rock flotation.

Jan 1, 2009

By K. Oraee

Rate of penetration of Tunnel Boring Machines (TBM) has a significant role in the planning, measurement of productivity and performance of any tunneling project. In this paper, the application of Adaptive Neuro Fuzzy Inference System (ANFIS) in prediction of TBM penetration rate is evaluated. For this purpose, a database including Rock Quality Designation (RQD), Uni-axial Compressive Strength (UCS) of the rock, the Distance between Planes of Weakness (DPW) in the rock mass, and empirical data regarding rate of penetration of TBM from several tunneling projects are collected. The Rate of Penetration is then estimated by using ANFIS. These results are then compared with measured TBM penetration rates (actual data). It is concluded that ANFIS can be applied successfully for such purpose and result in high accuracy for prediction for the rate of penetration of TBM. The method provided in this paper can assist the mining engineer to estimate the performance of tunneling accurately.

Jan 1, 2012

By J. P. Rider

The number of extended cut mining systems has increased significantly in coal mines over the last decade, and there is a constant push to extend the face ventilation systems to even greater setback distances. The need to maintain airflow at setback distances of12.2 m (40 ft) and beyond requires that methods for delivering intake air to the face be improved, or alternative ventilation techniques be implemented. The emphasis of this research effort was to examine various techniques to improve the distribution of available air at the mining face in order to reduce face methane levels. A study was conducted comparing the performance of a jet fan, used in conjunction with a machine mounted scrubber, with blowing curtain ventilation in a 27.5 m (90 ft) heading. In addition, a second study was performed on blowing curtain systems examining how scrubber flow, intake air velocity, and curtain setback influence face methane concentrations. Results showed that when the heading advances to a depth of 27.5 m (90 ft) blowing curtain systems were more efficient at diluting face methane levels when compared to a jet fan. Also, increases in scrubber flows and curtain velocity resulted in lower face methane concentrations for blowing curtain systems at 9.2 and 15.2 m (30 and 50 ft) setbacks.

Jan 1, 1997

By C. B. Clemmens

Accurately predicting ground control conditions before mining requires a comprehensive exploration approach including photogeologic mapping (satellite and low altitude), delta modeling and, particularly, geophysical logging. In situ properties, density; strength indices; grain size; clay content; and aquifer location, can be estimated with this inexpensive technique. Geophysical measurements can be spot-checked by field or laboratory tests on core samples and by hydrologic (pressure) testing. Each phase of drilling should be accompanied by refinement of the delta model, facilitated by log signatures. Measured properties can then be projected into geologically similar areas. A properly planned program will delineate both the "worst-case" and normal support conditions. Suspect areas can be avoided by mine layout and the mine plan can contain support contingencies for anticipated trouble spots.

Jan 1, 1985

By James S. Redpath

INTRODUCTION Background Early in 1972 our firm was asked by Cominco, managers of Arvik Mines Limited, to carry out an underground exploration programme referred to as the "Polaris Project" on a zinc-lead deposit in Canada's High Arctic. We had carried out numerous projects in the far north but this was to be the first long decline driven in perma-frost. Despite the short notice it was possible to meet the quickly approaching summer shipping deadline. We were able to do this by drawing heavily on our own and Cominco's background in Arctic operations. The project was an excellent example of owner-contractor co-operation and this spirit was responsible for the success of the project. Unusual Aspects There were a number of unusual aspects of the Polaris Project which are discussed in this paper. The extremely remote location, the short shipping season, and the fact that the work was carried out in permanently frozen ground, when combined with the lack of handy fresh water and a very severe climate, make it unique in many respects. Despite these handicaps, a record was set during the driving of the exploration decline.

Jan 1, 1974

By Aditya Rana, A. K. Mishra, M. M. Singh, N. K. Bhagat

Many cases of derailments, train accidents and traffic interruptions due to the slope failure and rockfall have been reported in the past on Konkan Railway trackline because of unstable rock slopes. The authorities installed stability enhancement measures such as wire netting, rock bolting and shotcreting which were found insufficient. The failed geotechnical measures prompted authorities to excavate the unstable slopes. Rock blasting is generally not preferred for the excavation of slopes along the transportation route. Stabilisation and widening of slopes by blasting need closure of the route for a considerable time. Discontinuing traffic on Konkan Railway route was undesirable as it connects two important port cities Mumbai and Mangalore. The paper presents an innovative directional controlled blasting (DCB) technique for excavating three unstable slopes (i.e. cuttings) in hilly terrain without disturbing the traffic. New empirical formulae for small geometry blasting to estimate burden and throw have been developed. A unique sequence of firing and excavation with powder factor varying between 0.04 and 0.39 kg/m3 irrespective of the actual free face was used for rock blasting. The process controlled the throw of blasted material over the track and resulted in a smooth and stable wall. The slope angle has been changed from 80 to 82° to 45–47° and probability of wedge, planar and toppling failures was eliminated. About 100 such accident-prone slopes (52 km cumulative length, 7% of total route) situated at discrete locations along Konkan Railway route were stabilised using the technique. No incident of rockfall and slope failures along these slopes has been observed after the stabilisation.

By Don Phelps, Christopher Tattersall, David McAllister

Located south of downtown Seattle, the Beacon Hill Station & Tunnels is the key section of the southern segment of Sound Transit’s proposed new LINK light rail system. This paper presents an overview of the design, which includes 4,300 ft of segmentally-lined bore twin tunnels and a deep mined station. With platforms located156 feet below grade, the station itself is only the second large-scale mined station in soil the US. Its complex geometry combined with variable soil conditions—sands, silt sand clays with slickensides—challenged the designer’s to come up with a SEM-based design that addresses the owner’s risk, cost and schedule concerns.

Jan 1, 2003

By Edward D. Elkins

CalMat Co. is one of the largest producers of construction aggregates in the United States. The CalMat Reliance plant is located in Irwindale, California, and is situated on an alluvial fan formed by the San Gabriel River. The fan deposits are of Quaternary age and were derived from granitic and metamorphic bedrock exposed in the San Gabriel Mountains to the north. The sediments are poorly sorted and range in size from large boulders to clay size particles. The coarse material is hard and durable and consists of quartz diorite, granodiorite, granitic gneiss, schist and minor amounts of volcanic rock. The matrix is comprised of silty sand with varying amounts of clay. Thin silt and clay lenses occur sporadically throughout the deposit. The clay content of the matrix and the degree of weathering of the coarse material increases with depth. Based on seismic data, the alluvial fan varies from 200 to 400 feet thick and overlies crystalline bedrock. The Reliance plant was constructed in 1971 and 1972. It has a nominal capacity of 1200 to 1400 tons per hour, and typically produces more than three million tons of aggregate products per year. Alluvial fan sediments are mined from a gravel pit situated adjacent to the plant. The material is fed through a mobile, 48- by 60-inch, in-pit jaw crusher, then transported by conveyor to the main plant to be processed. The plant is modern and highly efficient. It has a typical wet and dry circuit and is capable of producing a wide range of aggregate products. To extend the life of the plant, a 9,000 foot conveyor system is being constructed to connect it to a granite quarry operated by Azusa Rock Inc. The quarry is located north of Irwindale, and is 50 percent owned by CalMat Co. The conveyor will be used to export crushed rock from the quarry to Reliance. The existing plant will be modified to process the crushed rock.

Jan 1, 1995

By Alexander Filimonov, Yury Bloshteyn

The development of a high-efficiency control system for mine ventilation is a complicated scientific and engineering problem. As a result of high-costs and difficult conditions involved in experiments for the development and investigation of mine ventilation systems, simulation is a critical task in cost reduction and productivity. The paper presents the description of a universal simulation model for controlled aerodynamic processes in an Underground ventilation Network (UVN). The high-efficiency programming tool to design and investigate mine ventilation control systems (MVCS) is also suggested.

Jan 1, 1991

By Stanley W. Ivosevic, Mark E. Emerson

Introduction Metals exploration activity is moderately intense in the US despite the 1981-82 recession in the mining industry. Although exploration expenditures are significantly less than the 1981 peak, quality and goal orientation of current exploration are high. Major foreign and domestic mining companies as well as nonmetal companies had been attracted to invest in minerals in the US. Its capital markets, political stability, and open-door policy are attractive for hard mineral explo¬ration, particularly in the West. The approach was to either acquire fully or partially developed ore bodies through merger and acquisition, or to fund large scale exploration programs in search of bulk-tonnage deposits. The acquisition avenue has not proved the panacea envisioned for overcoming lack of substantive mineral development. Nor has the decentralized approach to exploration that was adopted proven cost-effective. The emphasis on gold, to the exclusion of all other commodities, raises questions regarding the direction of exploration in the US for the rest of the 1980s. Overview More than 300 companies are active in metals exploration in the US. These range from established, well-known domestic and foreign corporations to hurriedly incorporated, unknown companies financed by having promoted mineral prospects or occurrences of questionable quality. Junior companies tend to be oriented toward property entrepreneurship, rather than the development of minerals resources. These companies have helped maintain mineral lands from prospect to production by holding blocks of property intact during periods of exploration inactivity. This was done through promotional efforts, even though few properties that attracted major venturers proved to have real merit. Exploration objectives of senior and junior exploration companies currently embrace only a few commodities. Arranged in approximate descending order of priority, these are: precious metals; base metals in monometallic or polymetallic deposits; strategic metals, such as tungsten, tantalum, and tin; unconventional commodities, such as diamonds; ferrous metals; and commodities such as beryl, zeolites, and barite. Prospectors are important in searching for these targets. In the US, where they have been financed by major and junior companies, prospectors have proven a useful and low-cost means of locating gold prospects (e.g. the Alligator Ridge property in Nevada). The tenacity and persistence of independent prospectors have been factors in discovering properties rejected or overlooked by professional geologists (e.g. Lornex mine in British Columbia). This has been realized by the provincial government that grubstakes bona fide prospectors. Exploration interest in commodities has always been cyclic with price. Gold is one of the few metals that has experienced a price increase of such magnitude to warrant attention. The potential for realizing adequate operating margins for the Nevada open-pit "no-see-um" gold deposits is great. The present declining gold price, however, may indicate that this emphasis on gold, to the exclusion of other commodities, is shortsighted. Mining companies have been the last to react to price increases, opening new mines based on unrealistic market expectations. A scenario could develop where plummeting gold prices bring recession to the gold industry, as lately occurred in uranium, molybdenum, and copper. US Exploration Climate The US is attractive for exploration due to its strong mineral po-

Jan 4, 1984

By J-P Franzidis, M. C. Harris

Increasing costs, falling grades and a low gold price have caused severe problems for many of South Africa's gold mines. The need to maximise efficiency is extremely urgent. This paper describes the use of column flotation cell s to scavenge significant quantities of additional gold from flotation plant residues; in particular, very fine particles of free gold not recovered by conventional flotation. Experimental gold- specific collectors enhanced gold recovery significantly. The paper also reports the results of other plant trials, carried out on a variety of ores.

Jan 1, 1991

By Thomas P. Meloy

There is much interest in the automation of entire comminution circuits, At the present technological level it is possible to automate a circuit but to date it has not been done, To successfully automate a circuit, a number of problems must be solved. Not all of them are engineering problems. The purpose of this paper is to discuss some of these problems, as certain the implications of these problems and indicate solutions to them. In this paper the term "automation" is used loosely but in the popular sense. Namely, that a plant is automated if a computer is used to control the basic flow of the materials as well as setting the critical parameters in the process. Specifically, the discussion will concern itself with the control of comminution circuits from the dumping of the ore into the primary crusher until the final interface between the comminution circuit and say, the flotation mill in the case of a sulfide ore.

Jan 1, 1965