Search Documents

By S. B. Leonov, K. I. Popov, S. B. Polonsky

The offered technological line includes a flotation pulp air conditioner operating on the impact-mechanical effect and two column apparatuses with a descending pulp-air flow mounted in series. The technology developed makes it possible to increase considerably the valuable component in the concentrate simultaneously with a reduction in energy consumption for the flotation process. The experience achieved with the technology showed the possibility for obtaining sulphide silver-bearing ore superconcentrates with the noble metal content 2-10 times higher than that in the concentrates obtained by the conventional technology. The same results were obtained in the process of calcium-bearing boron-silicate ore-dressing.

Jan 1, 1995

By M. Liu

The use of surfactants shows great potential for the removal of hydrophobic organics from soils by in-situ washing techniques. Lab-scale soil washing experiments were performed using sodium dodecylsulfate (SDS), an anionic surfactant, and anthracene, a highly hydrophobic compound. The results of this research show that the solubility of anthracene increases linearly with an increase in SDS concentration above the critical micellar concentration. Furthermore, SDS can be effective in removing anthracene from contaminated sand.

Jan 1, 1993

By M. Sagisaka

Coal is expected as one of the main energy sources for a long period because of vast deposits. However, two large barriers to utilize it are suggested, i.e. the carbon dioxide emissions and ash disposal. The authors chose principal methods and areas to utilize coal ash and analyzed the environmental impacts caused by the ash treatment considering the source of the ash. According to the analysis based on lifecycle thinking, an optimized ash treatment system can reduce the integrated environmental impact. It suggests that coal can carry out its role for several decades without disturbances from the point of ash treatment.

Jan 1, 2006

By R. J. Lambert

The purpose of this paper is to discuss the application of mine design to the North DeLamar pit of NERCO's DeLamar Mine. Many discussions on mine planning and design focus on computerized mine modeling but neglect the final step of operating design development. Mine planning and design criteria used for the final layback in the North DeLamar pit are included along with a comparison of designed and as-built tonnages, grades and topography.

Jan 1, 1993

By Boris V. Vlasenko, Vadim P. Potapov, Gennady I. Gritsko

In this paper we consider the elements of an information geomechanic monitoring system which is used in computerized mine planning and mining operations control. The automated sys tem is a technical means of geomechanic monitoring, as a complex system of regulated observations, estimation and prediction of changes in geomechanic state of rock mass and workings during underground mining of coal deposits. Geomechanic monitoring at coal mines and the automated system execute data collection, analysis and calculations of geomechanic situation in the panel during planning, development and carrying-out of mining operations for ensuring geotechnical stability of underground mining.

Jan 1, 1996

By Ernest Selig, John Dunnicliff, Delon Hampton

This paper provides a summary of a two-day conference held in New Orleans in March 1980, entitled "Tunnel Instrumentation: Benefits and Implementation." The conference addressed two major questions: First, what are the benefits of using instrumentation during tunnel construction? Second, what contractual relations should be established for conducting instrumentation programs during tunnel construction? Each session consisted of brief formal presentations and extensive panel discussions with participation from attendees. Attendees included owners, designers, contractors, and instrumentation specialists. This paper presents a consensus of views expressed during the conference.

Jan 1, 1981

By Douglas R. Malicoat, Christopher J. Pritchard

Tg Soda Ash operates an underground trona mine located In southwestern Wyoming, which utilizes continuous mining machinery to produce 2.OM tpy (2.2M stpy) by shortwall and room and pillar methods. As the mine developed, the Increasing distance from the shafts caused travel times to be a significant factor in planning for mine emergencies. It was decided to construct a barricade chamber, a modified refuge chamber, to Increase safety and to provide an additional escape option in the case of a mine emergency. Fortunately, there has been no need to use these facilities during the last 9 years, but mine emergency planning has been greatly improved.

Jan 1, 1993

By W. A. Rickelton, A. J. Robertson

The ability of triisobutylphosphine sulfides to selectively recover silver from acidic sulfate solutions containing zinc and copper is described. Selectivity is explained in terms of the concept of hard and son Lewis acids and bases. Silver is stripped from the solvent using a novel strip feed (thiosulfate salt), and the recovery of metallic silver from the strip liquor by electrolysis or cementation is suggested. The high selectivity of extraction for silver and the utility of the stripping reagent are demonstrated in continuous, countercurrent, mini-plant tests. Important reagent properties, such as hydrolytic stability and low aqueous solubility, are discussed.

Jan 1, 1988

By Wang Dianzuo, Luo Lin, Hu Yuehua, Qiu Guanzhou

This paper introduces a novel classification approach named the flotation classification approach which works by controlling interactions between particles. It differs considerably from the conventional classification processes operating on mechanical forces. In the present test, the micro-bubble flotation technology is grafted onto hydro-classification. Selective aggregation and dispersion of ultrafine particles are achieved through governing the interactions in the classification process. A series of laboratory classification tests for -44 pm kaolin have been conducted on a classification column. As a result, about 92 percent recovery for minus 2 pm size fraction Kaolin in the final product is obtained. In addition, two criteria for the classification are set up. Finally, a principle of classifying and controlling the interactions between particles is discussed in terms of surface thermodynamics and hydrodynamics.

Jan 1, 1995

By Greg Joachims

Composition of salt in the Permian Flowerpot Shale in northwest Oklahoma suggests that the salt in this formation was deposited in the early phase of solar evaporation. Brine produced through natural dissolution of the subsurface salt has netted very pure brines, with relatively low concentrations of magnesium salts that should result from late-stage precipitation of salt deposits from sea water. Over the last 100 years, extensive studies of sea- water evaporites, in relation to brine density, have been a topic of discussion. The development of evaporation models has facilitated the increased production and purity of solar salt (salt produced through evaporation of brine by the sun's energy). Conversely, this information can be utilized to gain an understanding of how rock-salt formations were precipitated from sea water by analyzing the elemental constituents of the rock salt and of the resulting brine. By evaluation of well-documented, phase-curve tables of sea-water evaporation, a basic theory can be formulated on how the Flowerpot salt unit was formed.

Jan 1, 1999

By Zhou Aimin, Xie Benxian, Song Chongkai, He Zhexiang, Zhang Changqing

Concrete pump is commonly used to transport paste and high-density backfill over relatively long horizontal distances. However, since the investment in concrete-pump and its operating cost are quite high, the application of paste backfill is limited in China. For seeking an alternative paste backfill technology, squeezed-transport technique and equipment has been developed. The new technology has been adopted at Tonglushan Copper Mine of Daye Nonferrous Metals Corp for overcoming a difficulty of long-distance transportation of high-density cemented tailings fill. It proved to be an alternative paste backfill method with simple backfill system, saving investment and low operating costs.

Jan 1, 2001

By G. R. Wheeler

Epithermal gold exploration in the last decade has developed useful models for exploring previously overlooked ore districts in Oregon. In eastern Oregon, disseminated gold occurs in epithermal deposits that have been pervasively silicified and brecciated. Many gold prospects staked since 1980 are in fluvial and lacustrine sandstone and conglomerate deposits. Clay alteration products and disseminated pyrite may be present. Vein filling calcite and thin to thick quartz veins are common. Late stage quartz forms pseudomorphs after calcite in many prospects. Arsenic, mercury, and gold are geochemically anomalous but silver is usually not. The epithermal deposits are located in part of the Deer Butte formation or equivalent units. Exploration criteria include the presence -of Deer Butte formation or equivalent units and northwest structures cut by north-south basin and range structures.

Jan 1, 1987

By S. B. Bhagwat

Equipment capacities of a sample of Illinois surface coal mines representing about 60% of surface production in the state were studied. Available equipment capacity was compared with the required capacity, as indicated by coal production and stripping ratios reported. Most mines sampled showed surplus equipment capacity, which if avoided, would result in substantial cost savings. The surplus capacity results mostly from market fluctuations that result in underutilization of equipment. Study findings underline the importance of market assessment at the time of mine planning and of communication between marketing and engineering arms of a coal firm.

Jan 1, 1987

By Michael R. Smith

Barrick Goldstrike Mines Inc.’s Betze open pit is located at the north end of the Carlin Trend, in Eureka County, NV. Ten open pit gold mines exist on the trend, which strikes northwesterly, through the north end of Eureka County and into Elko County (Fig. 1). The final pit will be about 2440 m long x 1550 m wide (8000 x 5100 ft), elongate in a west-northwesterly direction and about 425 m (1400 ft) deep. The pit straddles the Barrick-Newmont Gold Co. property boundary. History The first hole at the Goldstrike Mine was drilled in 1962. Between 1963 and 1964, 17 shallow holes were drilled with little encouragement, in view of the price of gold at $1.12/g ($35/oz). From 1962 to 1975, several different companies explored the Goldstrike property. In 1975, Pancana Industries acquired the property. In 1976, Pancana’s exploration efforts found sufficient gold mineralization to initiate heap leach production. In 1977, Pancana formed a joint

Jan 1, 1994

By N. Pearson, F. Calizaya

PT Freeport's mine in Irian Jaya, Indonesia uses a number of 500 m (1,640 ft) long vertical ore passes to transfer ore from the open pit to the mill. The current tonnages moved are in the order of 125 kt/d (138,000 stpd) and this will be increasing to 240 kt/d (265,000 stpd). This amount of falling rock generates high pres¬sures in the ore bins, when ore feed is terminated the pressure is no longer constrained resulting in back blasting of materials and air the ore passes. Three methods were tested to try and eliminate or reduce this problem; recirculation the entrained air, widening of the orepasses and relieving the pressure the back blast. The final method proved to be the most effective in the short term. As a long term so¬lution the orepasses are currently undergoing widening.

Jan 1, 2000

By Terry Mudder

Long-term anaerobic biochemical treatment for draindown of residual solutions is a cost-effective way to close a heap-leach pad. This article presents a laboratory evaluation of anaerobic biochemical treatment of cyanide heap-leach pad solutions. The traditional approach to heap-leach pad closure is to rinse the pads with multiple pore volumes of fresh or recycled treated water. The effluent from an initial rinse is often treated and recirculated until the solutions passed through the heap meet the appropriate numeric and narrative water quality standards. Column rinsing tests are completed during project planning to determine the number of pore volumes of fresh or recycled treated water required to rinse the pad to meet long-term closure requirements. A traditional closure plan generally includes provisions to sample the rinse effluent and rinsed solids (the Meteoric Water Mobility, Procedure or USEPA 1312) to verify that chemical requirements are being met.

Jan 1, 1995

By L. J. E. Hofer, L. F. Zeiler, D. A. Giardino

The Jones Trickett Ratio (JTR) is generally used in investigations of fires and explosions for the determination of the composition of the fuel. This paper takes a close look at the JTR and finds it unreliable and ambiguous for the determination of fuel composition. A new index is presented, termed the (H/C) Index which uniquely determines the fuel composition. The (H/C) Index is simple to use requiring only the results of a single gas analysis of the combustion products. Experimental data testing the (H/C) Index for methane, propane, ethylene and coal dust are given, showing that the Index unambiguously determines the composition of the fuel. The (H/C) Index is also applied to the gas analysis data of several mine fires, illustrating how the Index changes with the progression of the mine fire.

Jan 1, 1993

By C. R. Bennett

A copper heap leach model, employing leading edge computational fluid dynamics (CFD) technology, is applied to the Zaldivar heap leach operation in Chile in order to explore and analyze the possible impact of operational changes. The effect of changes to the heap operation on copper recovery has been previously investigated and reported by the Zaldivar operation. This paper examines the extent to which a comprehensive heap leach model supports the analysis and conclusions of the published work. The heap is a complex multi-phase process, consisting of a solid static porous media with complex fluid flow, gas and liquid phases, competing solid-liquid reactions, dissolution of minerals and transport through the heap. The model accounts for the physical and chemical features of the heap, including transport and reactions kinetics for the important copper and iron sulfide minerals, ferrous oxidation, bacterial effects, thermal energy, acid and sulfate balances. The model was calibrated to published data on the ore body and employed to analyze the impact of a number of operational changes, including solution flow rate, acidity, lift height, crush size and head grade.

Jan 1, 2012

By N. ?peh

The purpose of the paper is to present a way of assessing nonrenewable lignite resources by means of sustainability indicators. An introductory presentation of the origin and characteristics of the discussed nonrenewable natural resources is followed by the study and analysis of separate sustainability indicators. Out of many, only the ones that would directly relate to the explored coal deposit were studied. Some different viewpoints such as economic, social and environmental were assessed inside the studied landscape structure and in relation to other provincial resources using the indicators that are closely linked with the explored lignite reserves. Exploitation of coal as an underground nonrenewable natural resource, has been taking place in the ?alek valley for more than 120 years. However, about 60% of the coal will still be left underground since not all coal will have been extracted when the mine closes. According to the regional and wider national strategic goals concerning the use of natural resources and electricity production in the future, the sustainable aspect of the exploitation of the geologically well explored reserves is emphasized in the paper. Finally, we have tried to evaluate the role and the meaning of the studied underground natural resources for further sustainable development of the ?alek valley and placed stress on the most questionable spheres that should be considered preferentially.

Jan 1, 2007

By Peter Kowalczyk

The acquisition of submarine gravity data using airborne gravity technology is a practical reality. Ocean Floor Geophysics plans to deploy a free-swimming ROV based submarine gravimeter on a commercial basis in early 2009. The submarine instrument is a variant of the well-used GT-1A airborne gravimeter. Airborne gravity surveys are now routine. The primary factor controlling the accuracy of airborne gravimeters is the precision of the GPS measurement of vertical movement of the sensor platform. The gravity measurements along a flight line are the differences between the output of the gravimeter vertical accelerometer and the estimate of the aircraft vertical acceleration using the differential GPS system. The principle difficulty of moving an airborne gravimeter to a free-swimming submarine platform is the necessity to have an accurate real time estimate of the changing elevation and hence changing vertical acceleration of the platform; GPS doesn't work underwater and an accurate estimate of depth fluctuations to the necessary precision is difficult to acquire. It is interesting that the airborne gravity gradiometer technology, which competes with the airborne gravity technology, was first developed as a classified military application for use by missile submarines during the cold war. Gradiometers were developed for this application specifically to avoid this problem. A gradiometer does not require as accurate an estimate of its vertical position to make a useful reading- it measures gravity gradients, not the gravity field itself.

Jan 1, 2008