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By V. N. Kolesnikov

The Sikhote-Alin part of the Circum-Pacific Ore Belt is characterized by wide distribution of Sn, Pb, Zn, W; Au, Ag, and other mineralization. This mineralization is regionally associated with the Late Cretaceous-Tertiary East Sikhote-Alin volcanic belt where it overlaps the Taukha accretiollary-wedge terrane of the Early Cretaceous age. The Pb-Zn deposits of the Dalnegorsk ore district may be grouped into the skarn (about 80%) and vein types. The skarn deposits are of major commercial value. Their geological position is controlled by the carbonate units located within tectonic melange of the Taukha terrane. Some other lithological and tectonic factors also play a significant role ill distribution of the mineralization. The ore bodies are traced to the depth of 1000-1500 m below the surface, having a pipe-lens shape and vertical zonation. Major minerals of the ores are galena, sphalerite, pyrrhotine, chalkopyrite, hedenbergite, quartz, and calcite. The minor elements of the Pb-Zn mineralization are cadmium, silver, bismuth, and copper. The paper describes relationships between mineral suites and minor element contents in the ores, as well as their significance for processing the ores. The metallurgy applied allows high recovering of the major components (Pb -93.9%; Zn -91.4%). However the tails contain some minor components that may be of commercial interest.

Jan 1, 1998

By D. R. Spears

As part of its mission to develop technology to assure a continuing supply of minerals, the US Bureau of Mines has investigated the flocculation of a Stillwater, MT, chromite ore. The ore was flocculated at different solids contents and at different stirring speeds to determine the importance and effect of hydrodynamic factors. In acidic and basic pH, the chromite ore was flocculated with high molecular weight polyacrylamides differing in the degree of hydrolysis. Polyacrylamides were found to bind to chromite ore particles through hydrogen bonding. The anionicity of the polymer and the pH affected the degree of polymer-particle interaction, which in turn affected polymer conformation at the surface. A polymer conformation with many loops and tails was used to explain high flocculation efficiency. It was found that such a conformation could compensate for poor hydrodynamic conditions.

Jan 1, 1992

By S. C. Suboleski

Forecasts indicate that the acid rain bill currently before Congress is likely to cause an increase in demand of 30 to 40 million tons per year of compliance quality coal from Central Appalachia. This represents a doubling of this segment of the coal business. This paper will examine how this doubling can be met, what the likely implications for pricing are, the major uncertainties associated with these predictions, and the likely outcomes of the growth in compliance coal. Finally, some implications for fuel planners will be discussed.

Jan 1, 1993

By M. C. Manderson

Phosphate rock is a naturally occurring mineral which, in upgraded form, is important to both agriculture and industry. Phosphate rock normally must be upgraded before it can be assimilated and used. Most of this upgrading is now carried out by chemical means, largely through the reaction of a strong inorganic acid (primarily sulfuric acid) with the phosphate rock to remove major impurities and to produce soluble phosphate. A less important but yet still commercially significant conversion method involves the thermal reduction of phosphate rock at high temperature in an electric furnace to produce elemental phosphorus. The elemental phosphorus is then converted to usable end products. This conversion route is a more costly method than the chemical route, but it has the advantage of being able to produce chemically pure phosphorus derivatives. On the other hand, the use of phosphate rock for agricultural application-primarily for use as a plant nutrient ingredient for fertilizer -does not require the same level of purity. As a consequence, the chemical method of phosphate rock upgrading is the predominant technique for producing phosphatic fertilizers.

Jan 1, 1977

By G. Falalakis

The Perama Hill gold project is an environmentally friendly project designed with the principle of zero discharge to the environment. The main issues of the proposed mine that are addressed in this paper are the water management, the dam and tailings management facility parameters as well as the mine closure plan, which demonstrate the sustainable design of the project. The water plant circuit will operate using 87% of recycled water and rainfalls, while the pumped aquifer is completely unsuitable for any other use. The proposed water management plan is based on different meteorological conditions for every month and optimizes the external water needs. The tailings pond area that is sited on intensely argilized rocks, will be composite-lined resulting in a permeability value of less than 10-10 m/s, and will exceed the safety parameters for maximum earthquake intensity, flood conditions and seepage. Tailings will contain less than 1 ppm cyanides (almost potable water ranges) and will be free of heavy metals (oxide ore material). The proposed rehabilitation plan comprises of decommissioning and demolition of the plant and auxiliary facilities, open pit partial back-filling and recontouring, appropriate capping of the tailings impoundment, revegetation, maintenance of area drainage system and monitoring for 5 years after rehabilitation. The plan is fullycosted, will be prepaid and through the agreed final land uses with the local community and the proposed actions of the corporate responsibility will attribute to the sustainable development of the area. The design of the Perama Hill project according to new EU and UN legislation and practices ensures that it will be the best example of gold mining operations in Greece.

Jan 1, 2008

By B. A. Firth

The presence of misplaced ultra-fine particles has been shown to decrease the separation efficiency of unit operations used in coal preparation. Although the classification of fine coal was considered to be adequate for the needs of the coal industry during the 1970's and 1980's, it has become apparent that further improvements in the yield/ash/moisture relationship achieved by coal preparation plants will require increased efficiency in this size separation step. This paper describes the issues which are evolving in this area, and the capability of current and developing techniques to address the problems which need to be overcome.

Jan 1, 1996

By J. D. Vincent

The Henderson mine site is located at Red Mountain on the eastern slope of the Rocky Mountains, approximately 50 miles west of Denver, Colorado. The mill site is on the west slope of the Rockies and mine and mill will be connected by an underground railroad. All designs were for a 30,000 ton per day molybdenite processing plant with provisions for future expansion up to 50,000 ton per day if required. This plan did not just happen, but slowly evolved over the course of about three and one-half years. Many plants cannot afford such a delay, but the Henderson project will take about 10 years from the time it was first discovered until production starts, and these 3 !1 years were well spent in determining the best possible plant site and flowsheet. This paper describes some of the problems and the decisions made in arriving at the final location and flowsheet. The paper does not go into the specific details of how protection of the environment went hand-in-hand with all other project considerations. This particular aspect of the planning has been well-reported on other occasions and considerable information on it is readily available.

Jan 1, 1972

By Hesam Dehghani, Farid Alimohammadnia, Nima Babanouri, Mokhtar Kalhori

In open-pit mining, blasting pattern design is performed to achieve a desired degree of fragmentation for loading, hauling, and crushing operations. Inappropriate fragmentation of rock will result in numerous problems such as incurring extra costs for secondary blasting, production interruption, etc. Wetness of the blast holes is one of the most important factors, which can cause the inappropriate rock fragmentation. Lowering ambient temperature in the vicinity of the explosion, the presence of water in the hole adversely affects the quality of the explosive while dissipating part of the explosion energy, ending up with inappropriate fragmentation problems. In the present research, in order to study blast-induced fragmentation conditions in Baba-Ali Iron Ore Mine, three scenarios were considered: explosion of ammonium nitrate with fuel oil (ANFO) in dry hole, explosion of ANFO in wet hole, and explosion of the emulsion in wet hole. For this purpose LS-DYNA, a numerical simulation code was used. Results of the present research showed that, compared to the explosion of ANFO in wet hole, the explosion of the emulsion produced more uniform distribution of fragment size, while the explosion of ANFO in dry hole resulted in fewer large fragments.

By Martha McJunkin, Lawrence Pietrzak

This paper describes and demonstrates the application of systems analysis and mathematical modeling techniques in the planning of actual tunnel projects and research and development to improve tunneling techniques. A recently completed tunnel project located in Utah is used as an example. Although cost estimating computer programs are used in tunnel project planning, the introduction of performance modeling, simulating the time to excavate, has added advantages that are explored here. The performance/cost tunneling model (TM) described herein mathematically simulates on a high-speed digital computer the important activities of a number of tunneling techniques accounting for activity interactions, variable external environments, mechanical failure, and other uncertainties. A cost accounting segment is included to facilitate cost-effectiveness comparisons. It is shown that, when combined with informed judgment and appreciation of limitations, the TM can be a useful tool that may help improve tunneling operations and cost estimation, for example, by achieving more balanced system designs or bounding the performance/cost implications of geologic and other uncertainties. Ultimately, this might lead to more competitive bids and greater profits. The need for systems analysis and modeling in tunneling research and development (R&D) is well recognized and documented.(1-5) In R&D one must seek broadly useful solutions to the basic problems of face fragmentation, materials handling, ground support, and environmental control. These solutions must take account of the interdependence of these elements and, for a variety of ground conditions, the limitations or constraints that any innovation in one element may impose on total system performance and cost. In this regard the structure and logic of the TM has been kept as simple and modular as possible so

Jan 1, 1974

By J. R. Hurley

The continuous flow, horizontal drum blender has dynamic properties which may be described by the same type of equations which often arise in electrical filter analysis. Furthermore, the equations may be readily solved by the same techniques used in electrical control analysis. For this reason the blender model developed is termed an "Electric Analog", although strictly speaking it is a mathematical model. Presentation of the dynamic performance of the blender as an electrical (or mathematical) model is desirable for several reasons. The model can be of assistance in correlating performance data with equipment design parameters. The model 'can be used with other process equipment models for simulation of an entire plant operation or in stability studies. In addition, the model may be useful in providing insight into the actual blending mechanism, or it may suggest a similar method of analysis for other closely allied equipment.

Jan 1, 1967

The dissolution behavior of gold and silver from Au/Ag alloys in aerated cyanide solutions has been investigated using rotating disc electrodes. The variables studied included concentration of cyanide, oxygen partial pressure and rotating speed of the disc. The dissolution potential and the rate of dissolution were obtained in view of the anodic and cathodic current-potential relationships. The results were discussed in terms of a mixed potential theory. The results showed that the dissolution rate of gold and silver from the alloys was partially controlled by chemical reaction, but largely by transport of either oxygen or cyanide, depending on their relative concentration under the experimental conditions employed in this study.

Jan 1, 1995

By T. W. Camm

One function of the U.S. Bureau of Mines is assessing potential economic impacts of federal land withdrawal policies. This often requires performing economic ana1ysls for an area with limited geologic information available. Input to the economic decision process relies heavily on estimates of mine and mill costs for the potential resources in the area being considered. A methodology for performing these cost estimates was needed to address this situation.

Jan 1, 1992

By A. J. P. Durham

Two low water flux test covers were placed on acid generating waste rack dumps at the Kidston Gold Mine in Queensland, Australia The climate is semi arid with distinct wet/dry seasons. The present study was initiated to develop a cover system to restrict infiltration. The design of the cover required optimization of water storage and evapotranspiration. Instrumentation was installed on both dumps to measure infiltration, moisture conditions and climatic parameters. Field measurements over the last three years indicate that both covers are performing satisfactorily. Selection of the final cover for closure is described on the basis of these results.

Jan 1, 2000

By William J. Shampine

The Floridan aquifer, which underlies all of Florida, yields water with a sulfate content of less than 50 parts per million in the north-western part and throughout most of the center of the State. In the southern part of Florida and along the most of the east coast, the sulfate concentration generally exceeds 100 parts per million and is as much as 1,700 parts per million. The sulfate concentration tends to be higher in the deeper zones of the aquifer. This map shows the sulfate concentration in the upper part of the aquifer. Sulfate is found in almost all natural water. Sulfate in rainwater is dissolved from impurities and gases in the atmosphere. Rankama and Sahama (1955, p. 314) report that the average sulfate content of rainwater is two parts per million; however, concentrations have been as high as 283 parts per million. Much of the sulfate in rainwater comes from hydrogen sulfide gas which is generated in shallow water on the continental shelves. The combustion of bituminous coal used for heating and industrial purposes seems to be an important local source of sulfate.

Jan 1, 1966

By C. M. Brinckerhoff

Much has been written in the mining technical magazines about the caving system. Many of these articles were published in the Transactions of the American Institute of Mining Engineers prior to World War II. In recent years little has been written on mining methods or on the detailed planning always required. Block caving had primarily been used to mine deep copper ores in Africa, the United States and in Chile, although other ores had been mined by this same system. Asbestos ore had been caved in Canada, tin ore in Bolivia, molybdenum ore in Colorado, iron ore in Wyoming and Sweden, and limestone in California.

Jan 1, 1984

By E. Pizarro

Division Andina has considered in its long range planning, the exploitation by panel caving method of "Third Panel" mine, which was started its production stage during the second half of 1995. This mine has two production levels, the first is grizzly level and another is L.H.D. level. Both sectors use the same haulage level where mineral is recollected through ore pass. For mineral loading and haulage its use 50ton diesel trucks combined with electro-hydraulic chutes. The automation has permitted what this operation is carrying out with remote control by driver's truck, in concordance to short range planning.

Jan 1, 1998

By Donald M. Duncan

An acceptable source of concrete aggregate is available in Kansas City in a continuous, medium bedded, slightly dipping limestone unit. Removal is accomplished in shallow depth, 12 feet to 17 feet high, room and pillar mines. The accepted empirical design spaces 20 foot pillars 60 feet on center. A portion of the 20 foot unit is left in place for roof support. Rock and soil cover is variable to 100± feet maximum. Long-term stability of these mines is affected by numerous factors, including the above mine-rock profile, ground water conditions and mining practice. Crusher-run aggregate sells at the mine for $2.20 per ton, yielding a gross income of $2.00 to $2.80 per square foot of mine. Use of mine space for real estate development requires a new perspective in mine development. Mining practices to obtain long term stabile structures can become an over-riding factor as compared with minimum production costs and maximum extraction ratios. Poorly mined areas are unusuable for secondary purposes. Development cost for lease space in less desirable mines is substantially greater than those planned for a secondary use. Real estate development in mine space involves unique engineering problems. Properly engineered developments offer singular advantages. Warehouse lease space sells for $.50 to $1.00 per square foot per year; fully developed office areas may double these values.

Jan 1, 1968

By Xiangze Shu, Yuzhong Xing

All programs used to optimize main fan nowdays have to be run on the large and medium- sized computers. With a lot of array elements, complex processes, low convergence speed and large storage, these programs are both time consuming and difficult to be used in the micro computer. This program uses two languages (dBASEIII and BASICA) to calculate the network and to choose the fan respectively. It allows user to compare and choose the parameters of various kinds of fan and to transfer the selected fan parameters to the master program by a data communication system. Then the user can get the air quantity, the air pressure, the power and the efficiency of the main fan. The advantages of this program arc as follows: 1. It can be run on IBM-PC or compatible micro computer. 2. It can select a fan more quickly and less time consumingly. 3. It can choose desired one or a set of fans according to user's requirements. 4. It is suitable for the research institutions and coal mines.

Jan 1, 1991

By G. J. J. Aleva, A. H. Hilversum

The northern spur of the Bakhuis Mountains contains bauxite deposits on a dissected planation level, a region formerly indicated as the Adampada-Kabalebo area. Iron-rich laterites are ubiquitous on all more or less flat and horizontal to moderately sloping interfluves and planation levels. The known aluminous laterites and bauxites are restricted to those laterites that have relatively leucocratic and silica-poor parent rocks. The whole area is underlain by high-metamorphic Precambrian. In the northern half of the Guiana Shield at least four Cainozoic planation levels can be distinguished. The bauxite and aluminous laterite deposits are related to the oldest, Early Tertiary level. These deposits, occupying the highest positions in the present day landscape, show the destructive influence of post-laterite weathering, erosion and denud- ation; they are erosion remnants and as such are of irregular thickness, grade and shape. Consequently, exact mineable tonnages can only be determined after intensive and detailed sampling and evaluation, taking into account the latest technical and economic parameters. The bauxite potential of the region is negatively influ- enced by the complicated uplift history of the Bakhuis horst, and positively by the presence of suitable parent rock and possibly more than one phase of bauxitization.

Jan 1, 1984

By G. J. C. Young

In 1986 the city of Johannesburg celebrates its first century of existence. The fact that the city was founded to exploit the gold deposits which underlaid it, prompts this review of the gold process development in the mining industry of South Africa. Clearly a complete history of, the gold recovery process to date is not called for and it is proposed therefore to outline the most significant developments which have taken place since the middle 1930's, that is to say the last 50 years or so. Prior to this period the industry had seen the development of comminution processes employing cone crushing in closed circuit with vibrating screens followed by grinding in rotating mills and the gradual disappearance of stamp mills. The all sliming process was well established as a viable route and continuous dewatering in thickeners, continuous leaching and filtration were serious rivals for the earlier batch processes. Continuous processes for gravity concentration had also been developed and the recovery of gold from pregnant solutions employed cementation on zinc dust as opposed to shavings. Thus at the beginning of the half century under review the industry had adopted, or started to adopt, many of the processes still accepted as modern practice. However in some areas little change was evident this was especially so in the smelthouse where some thirty more years were to elapse before the hand stoked coal fired calcine and reverbatory furnaces were replaced by more environmentally acceptable electric furnaces. The most significant feature in recent history has been the mining of progressively lower grades of ore and the retreatment of tailings from earlier operations, much of the latter comprising tailings only a decade or even less in age. Notable among these operations are those on the East Rand near Springs in the Transvaal, in the Orange Free State at Welkom and more recently, massive reclamation of tailings close to the city centre itself. The carbon in pulp (CIP) process has been much publicised in recent years and all new plants erected during the 1980's have adopted this route for gold recovery. However the major proportion of tonnage milled in the industry is still subjected to the more traditional process of liquid solids separation by vacuum filtration. The discussion that follows will centre largely on the developments in the traditional process route, which for the sake of completeness is listed below: Comminution Dewatering Leaching Liquid solids separation Gold recovery Smelting

Jan 1, 1985