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By Takashi Sakaguchi, Takehiko Tsuruta, Akira Nakajima

Some attempts were made to recover gold from aqueous systems using immobilized persimmon tannin. This adsorbent adsorbed gold from solutions containing hydrogen tetrachloroaurate (III) with high efficiency, whereas there was minimal adsorption from solutions containing gold (I) sodium thiomalate and sodium dicyanoaurate (I). The adsorption of gold was rapid, and was affected by the pH of the solution, temperature, external gold concentration and amount of adsorbent. Adsorbed gold was easily desorbed with 1 M thiourea solution, indicating that immobilized persimmon tannin can be repeatedly re-used for the recovery of gold using adsorption-desorption cycles.

Jan 1, 1995

By C. J. Lewis

Commercial lime plants in the United States and Canada are depicted in Figure 1. The sources of lime available to Nevada and bordering states are rather few. Chemstar Lime has plants at Apex, Nevada and Nelsen, Arizona. Continental Lime, Inc. has plants at Tacoma, Washington, Townsend, Montana and Delta, Utah. However, Continental Lime has a new rotary kiln installation underway near Wendover, Nevada. This plant is scheduled to come on stream in the fall of 1989.

Jan 1, 1989

By Rocky Gunderson

When operations begin early next year at the $100-million Port Kembla coal loading facility in New South Wales, Australia, a sophisticated computer system, directed by two of Hewlett-Packard's HP1000 mini-computers, will perform a number of functions ranging from monitoring and reporting arrivals and departures to maintaining a library of events for up to one year. The three-processor HP1000 system configuration, valued at $215,000, is one of the largest single orders, in terms of dollar value, ever submitted in Australia for Hewlett-Packard's line of engineering and manufacturing minicomputers. The processors will be linked in a fully "backed-up'' configuration using Hewlett-Packard's fourth generation distributed networking system, DS/1000-IV, making the system one of the most sophisticated in Australia. Interfaced to a number of weightometers and programmable logic controllers (PLCs), the computers will be the heart of a coal inventory system for the facility which, in its first phase, will be capable of handling more than 13.5 Mt/a of coal. The computers will report on all plant functions, including conveyor belt and water spray operations. Specifically, the system will: • Monitor and report all coal movements related to road and rail deliveries, dispatches from ship loaders, and interstockpile transfers. •Maintain a ''running log" of all events pertaining to overall plant operations, such as conveyor starts and stops and anti-pollution spray activation. • Accept and maintain plant data entered manually or acquired automatically from various remote locations via either visual display units (VDUs) or PLCs. • Maintain complete historical records of all transactions and related plant events for up to one year. • Provide a facility for stockpile management, modeling-type programs, and training or other simulation activity. The facility was designed with the following characteristics in mind, based on an analysis of requirements for an automated coal loading operation that would optimize productivity and be flexible to change and grow with facility needs and changing technology: • Continuous Operations-Due to the need for continuous plant logging and control, the overall facility will be capable of uninterrupted, 24¬hour operation. • Handling Current and Projected Workloads-The facility will be capable of not only handling current workloads, but also any additional workloads required during future coal loading operations. • Expansion-The facility will be capable of expansion, for a minimum cost, at any time with minimum disruption in operations. • Single Source of Supply and Maintenance-The facility will be supplied and maintained by one supplier, through hardware and software maintenance support contracts. System Configuration Two HP1000 minicomputers, each with 500K bytes of main memory, will be front-ended by a pre-processor with 256K bytes of main memory. These three systems, active, backup, and front-end, will be interconnected into a triangular array, as shown in the accompanying diagram. Under normal conditions, the front-end will transmit plant status data to one of the main systems, whose primary function will be to monitor coal flow and maintain a relevant dialogue with operators. The front-end, therefore, handles all communication with the plant PLCs, effectively removing this overhead from the current plant monitor (either of the two main systems). The front-end pre-processes and post-processes all information flowing from the plant monitor to the PLCs and vice versa, thus effectively handling all communication between the two units. A second main system will handle reporting, administrative, and modeling functions, and will also be capable of performing both front-end and monitoring operations. Linking all

Jan 11, 1981

By R. E. Johnson, W. Kat, B. R. Palmer, van Sandwijk A., G. Van Weert, S. Honingh

In-plant recycling of dust from iron making BF's creates undesirable circulating loads of volatile trace elements such as zinc and lead. Disposal of such dusts creates environmental problems, hence a separate treatment is indicated. Since the bulk of the zinc and lead compounds occurs in the fine dust fraction; hydrocycloning the slurry from the BF gas cleaning operation results in upgrading the material for treatment. A process has been proposed, whereby the zinc and lead are solubilized from the fine fraction with spent hydrochloric acid from steel pickling. The stoichiometry of this autoclave oxidation process is adjusted to simultaneously precipitate, by oxyhydrolysis, most of the iron for recycling to the BF's. Lead and zinc are successively recovered from the filtrate as low chloride precipitates. This paper describes additional testwork, leading to the design of a pilot plant which was planned to begin operation in 1992.

Jan 1, 1993

By Barbara J. Arnold

Combat Infantrymen’s Badge and Bronze Star Medal. Following his discharge from the Army, he re-entered SDSM&T in 1946 and earned a B.S. degree in Metallurgical Engineering in 1948. He then received an M.S. from Montana Tech (MT), worked several years in industry and then as an Assistant Professor at the University of Washington (Seattle). He joined his Montana Tech colleague, Douglas W. Fuerstenau, at The Massachusetts Institute of Technology (MIT), receiving his doctorate in 1957. While at MIT, he married Clare M. Donaghue of Dorchester, Massachusetts, in 1955

Jan 3, 2022

By Gerald Zink

The work described in this paper is sponsored by the Bureau of Mines for the purpose of accelerating the drilling of roof bolt holes and reducing the quantity of materials needed to fill each hole. A high-speed small-hole drill has been fabricated and tested in the laboratory. High priority has been given to safety, reliability, and compatibility with underground coal mining practice. The combination of drag bits and erosion jets is designed for high penetration rate, long wear life, and uniform hole size in a variety of sedimentary strata. A reliable high-pressure high-speed swivel feeds water to the bit at about 4 1/min (1 gpm). The duplex hydraulic intensifier which drives the jets has a 40 kw capacity (30hhp) Results of recent full-scale laboratory testing are presented.

Jan 1, 1978

By K. A. Brunk

This paper describes Newmont's research, operations, history and experience with pre-treatment of preg robbing carbonaceous ores. The chemistry, physics and kinetics of chlorine treatment are described. Present operations, control strategy and projected changes are discussed. Included is a summary of the adsorption of chlorine into pulps and off-gas scrubbing.

Jan 1, 1987

By C. R. Kuhn

From 1968 to 1975, most work in surface modification of inorganic materials involved silane coupling agents. A silane coupling agent can be described simply as an oganosilicon chemical having a general formula RSi-X3 wherein the R group is attached to a silicon in a thermally and hydrolytically stable manner, and X is a hydrolyzable group usually having an alkoxy functionality. About 1975, Kenrich Petrochemicals brought into the market place titanate coupling agents. Titanate coupling agents usually consist of one alkoxy group and three functional groups attached to a central titanium atom. Zircoaluminates became available in about 1982. Zircoaluminate organometallic coupling agents, which vary principally in their respective organofunctionalities, arise from a basic technology in which two different types of organic ligands are selectively bound to a low-molecular weight zircoaluminate backbone.

Jan 1, 1995

By W. Irwin

Global warming hitherto viewed as a distant threat to the environment, is now the subject of fierce goo-political debate. The debate centres around the time frame required to achieve environmental compliance, and the cost implications of meeting that objective. Since coal is the fuel of choice for power generation, the priority objective of energy producers is the pursuit of environmental protection measures that allow coal to be burned without any attendant negative impact on the environment. From an environmental point of view, public attention is today firmly focused on the impact that all industrial activity has on the environment, and coal is singled out from other fossil fuels as being the product of an inefficient smokestack industry. Despite coal's poor public image it is unrealistic to suggest as some do, that use of this fossil fuel as a primary energy source should be drastically curtailed. Coal which already generates about 35% of the world's electricity is continuing to increase its share of this rapidly expanding market, and to argue against its use is flying in the face of reality. However, changes are required in the way coal is used in some of the new clean coal technologies, since many include advanced methods of combustion. Indeed changes in the way coal is used is a vital link to the future of coal as a primary source of energy, and increased coal utilization will be directly linked to changes in its use. Discussion of various issues that affect coal utilization are the focus of this paper.

Jan 1, 1998

By Gerrit V. R. Goodman, Charles D. Taylor

A technique was developed to determine the fraction of air recirculated from the scrubber exhaust toward the face and the fraction of gas captured by the scrubber. To determine these two values, a series of tests was required. In the first test, gas was released at the face area and concentrations measured at the scrubber exhaust. In the second test, gas was released directly into the scrubber with concentrations again measured in the scrubber exhaust. The simultaneous solution of two independent flow expressions gave values of recirculation and scrubber capture. A series of tests was conducted with various combinations of scrubber flow, curtain flow, setback distance, and machine location. Statistical analyses then were conducted to determine those factors which influenced the levels of scrubber recirculation and scrubber capture in a deep cut. INTRODUCTION As cutting depths increase, the trend is toward the use of blowing face ventilation systems. With these ventilation systems, the potential exists for recirculation between the scrubber exhaust and the intake air stream. One concern is that methane gas, having been removed from the face area, is subsequently recirculated back into the intake airflow. Under these conditions, methane-laden air could be substituted for fresh intake air, leading to increased methane concentrations at the face. There is currently no standard for recirculation between the scrubber and intake airflows. The implied understanding of the Mine Safety and Health Administration (MSHA) is, and has always been, that any recirculation of ventilation air is unacceptable. To minimize recirculation potential, MSHA suggests that operators maintain scrubber and curtain flows within 0.47 m3/sec (1000 cfm) of each other. Given that recirculation may occur in some circumstances, the question arises as to how much recirculation constitutes a hazard for the face workers. Unfortunately, there is currently insufficient information to answer this. Emphasis must instead be placed on means to quantify the amount of recirculation between the scrubber and face area. Methods must also be examined to control this phenomenon. This paper presents a technique for quantifying recirculation and scrubber capture levels in a blowing face ventilation system. Several ventilation parameters are investigated to determine their effects on these levels. DEVELOPMENT OF RECIRCULATION EXPRESSIONS One way to measure airflow quantities at a point near the face would be to measure the gas flow rate Qgas, and gas concentration c at that location. The airflow Qair, would be simply the ratio of these two values, Qair, = Qgas/c. Although gas concentration values, c, can be obtained easily with existing gas monitoring equipment, it is more difficult to obtain gas flow readings, Qgas, at specific locations. To obtain these values of Qgas, another method was needed. Previous work in this area was conducted by Kissell and Bielicki (1975). However, the calculations in their model assumed a constant gas concentration in the region around the continuous miner. In a deep cut, it is questionable that gas concentrations would remain constant or uniform around the mining machine. The technique presented here does not rely on this assumption. It instead assumes that the gas concentration in the scrubber exhaust remains constant. A quantity of gas released at the cutting face either flows into the scrubber inlets or bypasses the inlets and flows around the off-curtain side (in this example, the right side) of the continuous miner (Figure 1). The fraction of the face gas that flows

Jan 1, 1993

By Jeffery Denit, Steve Hoffman, Van Housman

The Environmental Protection Agency (EPA) is in the early stages of developing a national mining waste program. Our goal is to develop a mining waste program that will be state implemented, multimedia in nature, flexible, utilize and enhance existing state programs, and protect the environment. The Agency appreciates the cooperation the mining industry is providing through its participation in the Policy Dialogue committee on Mining and by providing the Agency with technical data. The following is a discussion of what led to the development of a national mining waste program, the agenda initiative to evaluate Toxic Substances Control Act authority in phosphate manufacturing, and the important steps being taken through the Policy Dialogue process to frame and discuss issues. EXTRACTION AND BENEFICIATION OF ORES The Resource Conservation and Recovery Act of 1976 (RCRA) and subsequent amendments created a framework for the regulation of hazardous wastes under Subtitle C and nonhazardous waste under Subtitle D. In 1978, initial regulations were proposed for hazardous waste management units under RCRA. These identified a universe of special wastes that were large volume, low hazard and less amenable to Subtitle C control techniques. EPA noted that waste materials from the "extraction, beneficiation and processing of ores and minerals m fit these criteria. In October 1980, Section 3001 of RCRA was amended. This Bevill amendment excluded solid waste from the extraction, beneficiation and processing of ores and minerals from regulatory control under RCRA's hazardous waste Subtitle C. This was done pending a report to Congress and a regulatory determination regarding the Subtitle C status of these wastes. Thus in November 1980, EPA published an interim final amendment to the RCRA Subtitle C regulations to reflect the Bevill amendment. RCRA requires EPA to perform studies and make reports to Congress regarding the management methods and potential hazards of managing waste. RCRA also calls for a regulatory determination regarding whether Subtitle C (hazardous) or D (non- hazardous) controls are warranted for these wastes. In December 1985, EPA submitted a report to congress entitled, “Wastes from the Extraction and Beneficiation of Metallic Ores, Phosphate Rock, Asbestos, Overburden from Uranium Mining and Oil Shale." In that report, EPA found that some mining wastes exhibit hazardous characteristics, that the range of risk from mining waste is broad, and that waste management practices have caused environmental damage. In July 1986, EPA published a regulatory determination based on information gathered in the 1985 report to Congress and comments from interested parties. In the report, EPA concluded that RCRA Subtitle C regulation of extraction and beneficiation wastes was unwarranted because mining wastes tend to be disposed of in arid climates, waste volumes are high, and facilities and wastes are located in sparsely

Jan 1, 1992

By P. Bottomley, M. Matthews

Maintaining an acceptable thermal environment in South African gold mines becomes increasingly difficult as mining progresses to greater depths where higher virgin rock temperatures are encountered. Current environmental practice offsets the resulting high heat loads by installing large refrigeration plants. However, with the continued escalation of refrigeration costs, it has become necessary to examine other methods for economically combatting the underground heat load. The Chamber of Mines Research Organization has recently been pursuing a programme to devise methods of reducing the flow of heat into underground workings at source. Although there are several sources of heat (such as machinery, men, and explosives), the most significant is that from the rock mass surrounding the workings (Bluhm et al., 1986a). The main thrust of the work has therefore been directed at predicting and devising methods of reducing this heat source. A great deal of theoretical work has been carried out on the prediction of underground heat flow. From a review of this work (Bluhm et al., 1986b) it became apparent that there are two major aspects which require attention, namely algorithms for predicting the heat flow around the advancing stope face, and a correlation of the theoretical work with accurate empirical data. In order to remedy this situation, new theoretical models have been developed (von Glehn and Bluhm, 1986), and heat flow measurements have been made in both a conventional stope (Bluhm et al, 1986a) and in a backfilled stope (Matthews u., 1987). A number of methods for reducing rock heat flow are being examined. These include the insulation of intake airways (Bottomley, 1985 ), backfilling with waste material of the worked out areas, and alternative approaches to the design of mining layouts, the mining method, and the choice of cooling strategy. This paper highlights the heat load reductions that can be achieved by backfilling the worked-out areas and by adopting concentrated mining. The first part of this paper summarizes the results of the measurements obtained in the conventional and backfilled stopes. The theoretical models are then described and comparisons are made with the measured values.

Jan 1, 1987

By D. Kelley

Due to pricing volatility and lack of availability of metals, the use of non-metallic materials of construction in metal extraction and refining processes has increased significantly in recent years Even though costs and availability of metals has improved recently, these factors are not expected to continue into the future as metal supplies once again fall short of global demand. One of the most common non-metallic materials of construction used in metal extraction and refining processes today is Fiberglass- Reinforced Plastic (FRP). These processes often require materials of construction that can resist acids and high concentrations of acid chloride salts. As shown in Table 1, FRP based on epoxy vinyl ester resin has the same chemical resistance to acid and better resistance to acid chloride salts than alloy C-276 and is superior to 2205 stainless steel in both cases.

Jan 1, 2010

By Robert P. Edwards, Brian C. Flintoff

Crushing plants (multiple stage) are an integral part of most conventional comminution circuits (ball mill, rod mill - ball mill). Although conventional circuitry is now the design exception, there are still many older, and some newer plants that include crushing in the process flowsheet. In most of these installations the operating objective is to maximize throughput at some minimum product size, in an effort to balance the comminution load between crushing and grinding. To achieve this goal, while avoiding production losses due to overloads, generally requires the use of automatic control strategies. This paper reviews the crushing plant control problem and describes several approaches that have been successfully implemented in different plants.

Jan 1, 1992

By Jiro Yamatomi, Susumu Takemura, Osam Sakai, Hiroshi Shimotori, Yoshio Otsuka

The Toyoha Mine is operated under extremely high rock temperature. The geothermal heat is 10 to 20 times more active than the average of the Japanese Islands. The highest temperature ever observed in exploration drill holes is 242°C that must be equivalent to those of the geothermal fluids utilized for power generation in Japan. In order to improve the underground climate, the mine has a plan to introduce paste backfilling and to effectively reduce the heat flows from the mined out stopes. The surface flow test was carried and the second test is being arranged in underground.

Jan 1, 2001

By P. D. Roa, O. Noirot, H. Owens, D. E. Walsh, J. R. Mokka

Over a period of eight years (1989 through 1997) the Mineral Industry Research Laboratory (MIRL) at the University of Alaska, Fairbanks, AK, has investigated the effects of temperature, residence time and particle size on the degree of low-rank coal (LRC) upgrading for a nonevaporative, hydrothermal drying process, also known as hot water drying (HWD). The following three Alaskan LRCs were used in this study: Usibelli coal (Seam No. 4) from the Nenana Coal Field, Little Tonzona coal from near McGrath, and Beluga coal from the Beluga-Yentna field on the west side of Cook Inlet. Replicated factorial tests were conducted. Experimental results indicate that most of the low-rank coal upgrading via HWD occurs rapidly within the first 10 to 20 min of residence time. Thereafter, the upgrading process slows down, and more than 100 min of additional residence time is required to produce percentage increases equivalent to what was achieved in the first 10 to 20 min. The properties of the hot water dried products were very sensitive to process temperature. Calorific value, carbon and oxygen contents, equilibrium moisture levels and Hardgrove gindabilities all appear to change linearly with temperature within the 275°C to 325°C (525°F to 61 5 OF) range.

Jan 1, 2000

By Arafat Ghosheh, Yousuf Abu-Rish, Darwish Amara, Mohammed Baderkhan

The Jordan Phosphate Mines Company is one of the world's major phosphate rock and phosphatic fertilizers producers (the second largest phosphate rock exporter), with ore reserves exceeding 2 billion tonnes, mainly located in the Eshidiya area. The Eshidiya phosphate deposits, 120 km north-east of Aqaba, are of sedimentary origin (as are all phosphate ore in Jordan). Three exploitable beds (Al, A2, and A3) with variable content of P205, CaO, SiO2, etc., are processed in order to produce 68-70,73-75, and 75-77% TCP grades. The A3 bed, which is characterized as the most siliceous containing 40-48% TCP, requires physical beneficiation using wet scrubbing, screening, and desliming by hydrocylone, followed by anionic conventional flotation to achieve 75- 77% TCP grade. For the last 15 years extensive laboratory and pilot tests (including physical, chemical, and mineralogical studies) were carried out. After operating the industrial plant, certain modifications were deemed necessary to adjust the operational parameters and the final flowsheet, which was followed to obtain the targeted quantity and quality of concentrate.

Jan 1, 1999

By Paul J. A. Lever

The mine environment is dynamic and operating conditions change continually and are difficult to predict. New equipment, variable geological conditions, modified layouts, and different equipment operators make monitoring and control system difficult to apply without continual software maintenance. The paper reports on algorithms that were developed, encoded with Knowledge Craft Tools, and tested on underground coal mine data to adapt to the dynamic environment. The system receives data from sensors in near real time and then identifies patterns in the data. Using a set of mode features the data is automatically checked to determine the present operating mode. When the operating mode changes from the previous shifts, the system automatically learns the new mode characteristics and uses that mode context for further data analysis. The concepts presented in this paper are applicable to a wide variety of mining scenarios, not just underground coal mining.

Jan 1, 1992

By D. S. Cavers

INTRODUCTION This paper discusses aspects of rock engineering applicable to surface gold mines. Discussion particularly centers on areas in which rock mechanics can enhance the mine productivity or profit- ability. Methods of analysis are discussed briefly but for more detai1s the reader is referred to the appropriate references. A team approach to the overall design of the pit generally pro- duces a better result at an overall lower cost. In particular, money is wasted by asking for a "report on slopes" and then input- ting this slope angle into a pit design and economic analysis study without further reference to the geotechnical engineer. Pit slope angle depends on slope orientation, location, pit shape, pre-existing discontinuities and mining methods. Preliminary slope angles can be produced but optimization depends on ongoing inter- action between the mining engineers, geologists and geotechnical engineers. This interaction can a1 so substantially reduce overall design time which may be critical in bringing remote plays into production. Most surface gold mines in North America are in igneous or metamorphic environments. Rock mechanics aspects discussed in this paper will be discussed with reference to these environments al- though most of the principles and comments are applicable to sedimentary environments as we1 1.

Jan 1, 1987

By Michael Drozd

The operation of an activated charcoal system has five separate unit operations. These unit operations have common points for CIP, CIL and CIS system, which vary widely in application. a. Absorption b. Desorption (Stripping) c. Acid Washing d. Reactivation e. Carbon Handling ( carbon transportation, sizing, de­watering, etc.) Cost optimization starts with the basic operating parameters (design philosophy) set down at the time of engineering design. This parameters undergo almost immediate change due to site specific ore requirements, throughput changes, operator requirements or reagent availability. Activated charcoal is sometimes viewed as simple, uncomplicated reagent that requires not optimization. To some extent, this statement is true, but under most circumstances, if the time necessary to optimize the use of activated charcoal is available, the effort is rewarded with significant savings. CPL-Carbon Link has embarked upon a program of supplying technical support with its activated charcoal. Several operation in the United States have under taken to have CPL-Carbon Link do an operational survey to determine if potential savings are possible. CPL-Carbon Link has offered to do these surveys for projects that are clients or simply would like to have CPL-Carbon Link review their operation. The information accumulated by CPL-Carbon Link is being used to attempt to fashion industry standards so that a common reference point came be establish for activated charcoal usage.

Jan 1, 2000