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By Surendra K. Mishra

Recent land ban act has put pressure on industry to decontaminate the waste streams before they could be discharged. However, for both metal and organic contaminated wastes, there are commercial incentives to recover usable resources. Recent technology developments have helped meeting such objectives. This paper reviews developments in treatment technologies for industrial wastes. Major chemical groups used in waste treatment are summarized.

Jan 1, 1994

By M. J. Zdunczyk

Sand is one of the most common materials on the earth’s surface. It is a naturally occurring material resulting from the physical and chemical breakdown of rocks. The definition of sand varies, as do the number of products made from the material. Sand is generally classified by grain size, however the measurement or scales differ depending on the context in which it is being used. Geologist define sand as particles of rock between .05 and 2 millimeters in diameter. The variability of the mineral composition generally dictates which sand can be used for different industrial purposes. For example, sand used for Portland cement concrete and asphaltic concrete mixtures can be very different in physical and chemical composition than sand used in the making of fiberglass. In this paper, construction uses of silica sand, which consists almost entirely of the mineral quartz (SiO2), will be discussed and analyzed.

Jan 1, 2001

By Barbery G., A. Maachar, M. Bourassa

Laboratory testing for flotation circuit design is carried out on a routine basis in a large number of lab- oratories throughout the world. Usually a sample of ore, assumed to be characteristic of the material to be processed in a future plant, having a mass of the order of a few kilograms, is ground in a batch ball or rod mill, in the presence of water and some re- agents (for pH control, etc. .. ); after dilution to the adequate solid concentration, the resulting slurry is transferred into a laboratory batch flotation machine, having a volume which can vary from 0.5 to 8 10 -3m3. Various types of machines are in common use, manufactured by the same companies that market industrial size flotation machines. The operation of flotation in the laboratory is carried out by an experienced technician, who uses parameters such as impeller rotation speed, air flowrate addition, froth height, froth removal rate, in conjonction with reagent addition sequence, to "test" the ore. After flotation, the froth products ("concentrates"), and the solids remaining in the cell are filtered, dried, and analyzed for the various elements of interest. For flotation circuit design, a kinetic test is usually carried out, in which the froth products obtained at various times are collected to assess the time response of the ore in the laboratory machine with the combination of reagents used. Although this description is rather sketchy, it enables to outline some of the major difficulties in using laboratory data for flotation circuit design: 1. ore sample representatively 2. feed preparation procedure (laboratory compared to industrial scale) 3. laboratory procedures (type of ma- chine, type of operation, experimental errors. . . ) 4. flotation machine scale-up 5. flotation kinetic scale-up 6. flotation circuit design using laboratory data These various points will be discussed in the present paper, in order to stress the problem areas as well as possible solutions. ORE SAMPLE REPRESENTATIVITY It has been stated many times that one of the major problem in designing a flotation circuit is the representatively of the sample to be taken. Sampling of an ore body during prospection and evaluation is a specialized field, which has been progress in with the introduction of geostatistics. The application

Jan 1, 1986

By Lawrence Pelham

The importance of fluorspar to the United States and the world and the role it plays in industry and society extend far beyond that which is suggested by its measured production and consumption quantities and declared value. Compared to many other industrial minerals, the annual worldwide consumption of 5 million short tons valued at less than $500 million are not impressive figures. Fluorspar is made special primarily because of its status as a critical and strategic commodity; it is essential for the processing of most steels and all aluminum. It also is the raw material for the production of elemental fluorine, which plays a part in uranium refining.

Jan 1, 1988

By David J. Starbuck

For small precious metals mining to show a comeback a different perspective must be taken than that of larger mining companies. This perspective must be much the same as that of past successful smaller mining enterprises such as when the US had a need for Uranium. Abandoned mines and environmental concerns in older mining districts have discouraged many from entering with the attitudes of why try there if so many unsuccessful mines exist. A small mining venture can be successful there but must have a "think smart'' attitude. There must be a thorough understanding of deposits, utilization of advanced technology and a properly managed mining operation. "THINK SMART" MINING The small mine operator is usually looking for small high grade deposits, consequently, long term success depends on a series of small successful mining operations. The small miner must succeed right-off or credibility and future project funding will suffer. No veteran of even a few years in the mining industry needs to be told that a dollar spent on production today fails to yield as much as it once did. More efficient equipment and techniques have helped soften the problem, but there is little likelihood that a mining company can do much to control inflation, wages, regulations, or grade. That leaves the small miner to "think smart" as one area where operating dollars can still be stretched to produce more than they presently do (Gardner. 1981). In the planning stage of a mining venture, when most options are still open, the main controllable elements are market timing, deposit selection, cutoff grade, mining method, mine design, mining sequence, rate of production build up, process design, project financing structure, project management, and project ownership structure. During planning, optimum criteria can be established for each of these. Once a mine is in production, these options are foreclosed or at least severely constrained. The more thought given to a mining program using all information available the less the risk of encountering disabling surprises. Thus the intent of this paper is to suggest the "think smart" attitude most small mine operations use for long term success. If one looks at a number of successful mining ventures, whether large or small, there is a general logic most have followed to be successful. They have used proven exploration, mining and processing techniques along with economic evaluation and experienced personnel to improve their odds. LOGIC IN DEVELOPING A FEASIBLE VENTURE Most successful small mine ventures achieve positive cash flow as quickly as possible by seeking out those deposits which require the least time and expense on activities leading up to production. To do this they look for deposits that are the most accessible, easily investigated, mined and processed with the cheapest fundamental methods. The general sequence of events starting with district selection are deposit selection, preliminary feasibility, exploration, detailed economic feasibility, mine planning, development and production. Each successive step becomes more costly requiring intermediate decisions along the way. District Selection Small operations should look for known deposits which favor the occurrence of the type deposit sought rather than efforts in unproductive areas. Known deposits in developed areas have some advantages over remote areas: 1. More alternative methods of transportation are available. 2. A larger stable work force is available. 3. The area is usually more pro-mining. 4. Power, water, housing, technical services, skilled services, schools, recreation and shopping are available.

Jan 1, 1987

The main goal of this paper is to present readers with recommendations for choosing coaxial cables appropriate for mining applications of Time Domain Ref 1 ectometry (TDR) to monitor rock mass movements. Prior to discussing the recommendations, mining applications are illustrated with examples and the operating principle of TDR is discussed briefly. Items that affect the result of the monitoring system performance include the coaxial cable selected, the grouting material used, and the installation procedure.

Jan 1, 1986

A roof rating system has been devel¬oped for upper seam damage prediction during mul¬ti-seam mining based on structural and geologic conditions in the upper seam. Two primary consid¬erations -geologic and spatial - form the basis of the classification system. It includes factors commonly found in geomechanics classification systems as well as factors which are peculiar to multi-seam mining, such as those which define the two adjacent seams and the innerburden. This rating system has been applied to numerous case studies to form empirical relationships for quan-titatively predicting potential upper seam damage based on anticipated subsidence and strain values and vertical movements.

Jan 1, 1988

By David R. Baughman, Ray V. Huff, Paul D. Chamberlin

ISL Ventures, Inc. (ISLV) is developing a process for recovering gold and silver from ores using a chloride-hypochlorite lixiviant. The leach solution, composed of water, NaCl and NaOCl, is maintained at a pH of about 7. At this pH most base metals are not leached. This is important for deposits that contain cyanide-soluble copper. An inhibitor can be incorporated to slow the decomposition of the oxidant. This paper reviews the history of development, presents details of the chemistry and indicates the nature of deposits, which we believe to be amenable to production using the process.

Jan 1, 1999

By D. C. Yang, J. Ye

A comprehensive flotation study has been conducted on a Chinese fluorspar ore using the packed flotation column developed at Michigan Technological University (MTU). The results are compared with those for a conventional mechanical flotation method on the same feedstocks. Key factors controlling flotation performance of both methods are evaluated based upon a simple statistic design. The flotation concentrate produced in one stage of the packed column has 4% to 5% higher recovery and much lower silica impurity than the concentrate produced by up to six stages using a conventional mechanical cell. The results also show that the packed-column flotation process is particularly suitable for the recovery of finer fluorspar particles.

Jan 1, 1993

By Richard Keith Corbin

INTRODUCTION With the world media full of predictions that the price of gold will quadruple in three years (Maybury, R.J., 1988), and with financial forecasters and strategists touting opportunities to make 400% in gold (Skousen, M., 1988), explorationists and entrepreneurs are scurrying to find enough gold to feed the global gold fever created. At the same time, gold deposits in the United States and other developed and intermediate countries are becoming less attractive because of environmental restrictions, radical reductions in tax incentives, and depleting reserves, causing people in the mining industry to begin looking at opportunities for foreign investment in gold mining concessions in lesser developed countries (LDCs). Meanwhile, LDCs are responding with chamber-of-commerce aplomb in marketing their opportunities. In the face of all this frenzy and hype, targeting gold mining concessions in LDCs for foreign investment may be done more objectively by employing a systematic approach. For this paper the SHOP rating system (Corbin, R.K., 1987), which considers factors of the LDC's stability, hospitability, ore occurrence, and profitability potential is used. The result is that a tiny banana-growing republic in Central America, first discovered by Columbus and named the "Rich Coast'' because of the many gold adornments worn by its Indians, has been rediscovered and emerges as a classic LDC gold target.

Jan 1, 1988

By J. Hazen, R. Jenner

This project was developed at the PCS Phosphate Mine in Aurora, NC. This site includes a surface mining operation, beneficiation plant and chemical processing facility located in the coastal plain of eastern North Carolina. The phosphate ore being mined at this operation is a 10 to 12 meter (35 to 40 foot) thick colloidal deposit located approximately 30 meters (100 feet) below the ground surface. The ore is pumped to the beneficiation facility where it is separated into clay, sand and concentrate streams. The concentrate product is utilized at the chemical plants to produce a wide range of products including fertilizer, industrial phosphates and animal feed products. The Cyclone Dike Builder (CDB) project developed a technique for dewatering the beneficiation tailing sand stream and providing innovative placement for dike construction. Future material balance requirements at the PCS Phosphate mine required an improvement in tailing sand placement technique to accomplish strategic objectives. The water volume of the sand slurry forces significant quantities of sand out of the dike profile during deposition. PCS Phosphate and MetPro Supply of Florida developed a mobile high-density hydro-cyclone station to remove most of the water and significantly increase the density of the sand being placed for dike construction. This high-density sand slurry is then effectively controlled using minimal heavy equipment operation.

Jan 1, 2004

By R. M. Rowe, A. K. Bhasin, D. Malhotra

Introduction Most primary molybdenite producers use a selective flotation process in which molybdenite is floated from the ore while other sulfide and nonsulfide gangue minerals are depressed in the same step. The process was developed at the Climax mill. Reagents used in the rougher flotation stage include vapor oil (collector), syntex (surfactant), pine oil (frother), and occasionally sodium cyanide and Nokes reagent (depressant). Rougher concentrate is upgraded by cleaner flotation to produce market-grade molybdenite concentrates. Reagents used in the cleaner flotation stage are Dowfroth 250, vapor oil, sodium cyanide, and Nokes reagent. The development of the flotation reagent scheme at Climax and the role of the reagents have been well described by Born et al. (1976) and Malhotra et al. (1976, 1977a, 1977b, 1977c, 1980). The hydrocarbon collector, vapor oil, accounts for approximately 50% of the total molybdenite flotation reagent cost. Because vapor oil sources are limited, and the cost of vapor oil has increased significantly over the last decade, several studies have been done to evaluate alternate oil-based collectors and/or blends of collectors that would produce similar metallurgical results at a reduced cost, or increase the overall molybdenite recovery at the same cost (Smit and Bhasin, 1983; Hahn, 1969; Smith and Bhappu, 1971). The approach taken in the present study was to evaluate alternate nonoil-based collectors and collector systems that are less expensive than vapor oil. A series of potential nonoil-based collector classes were identified and evaluated in the laboratory against the current collector system. The metallurgical performance of these collector classes was related to their chemical structures. The results of this study are discussed. Collector classes A survey of sulfide mineral collectors was performed with the objective of identifying and selecting potential collectors for molybdenite flotation. The available reagents were categorized into 10 general classes. Table 1 summarizes these collector classes, their chemical formulas, the manufacturers, and selected commercial collectors in each class that were evaluated in the present study. Experimental procedure A Climax ore sample, assaying 0.3% MoS2, 2.2% FeS2, 0.007% Cu, 0.003% Pb, and 0.03 oz per ton Ag, was used for this study. Standard laboratory rougher flotation test procedure involved grinding a 2-kg ore charge in a rod mill at 60% solids. Reagents were added to the rod mill including a collector, syntex (0.005 kg/t), pine oil (0.03 kg/t), lime (to adjust pH to 8), and sodium silicate (0.15 kg/t). The ground pulp was transferred to a 1000-g cell, and flotation was performed at 35% solids and 1800 rpm using a Denver D-1 flotation machine. Concentrate was collected for a flotation time of six minutes. The general approach used in the present study was to substitute the nonoil-based collectors at two to three different dosage levels (0.01 to 0.15 kg/t) for vapor oil in the bench-scale, open-circuit rougher flotation tests

Jan 1, 1987

By J. Patrick Powers, Arthur B. Corwin

Modern improvements in hydrogeology make it possible to predict with good reliability the performance and cost of ground water pumping systems in many tunneling situations. The testing and analysis techniques are presented. Data from the Buffalo NY LRRTS (1978-1980) illustrate the successful application of the technique for tunneling in rock. Data from the Red Hook Interceptor Tunnel in Brooklyn NY (1978) illustrate the application in soft ground. The Red Hook project also illustrates concerns for the side effects from dewatering, such as ground settlement and damage to timber structures. At Red Hook protective measures included compressed air, artificial recharge and controlled dewatering. Given the uncertainties of the underground, the possibility of unexpected situations must be considered. A hard rock sewer tunnel in Atlanta, Georgia (1982) illustrates an unexpected problem, and the emergency measures used to solve it.

Jan 1, 1985

By John E. Urbanic, William D. Faulkner, Robert W. Ruckel

Guidelines are presented for the selection, handling and regeneration of activated carbon used in gold recovery operations. The guidelines are based on Calgon Carbon Corporation's own investigations and experience gained in working with gold mine operators all over the world. Gold adsorption rate and adsorption capacity are shown to be independent variables thereby requiring testing of both properties when selecting activated carbon. Means of measuring these properties are provided. Historical activity tests on activated carbon are shown to be minimally useful in selecting carbon for gold recovery. Proper thermal regeneration techniques to maximize recovery of adsorption rate without weakening the carbon structure are suggested. Simple positive means of measuring efficiency of regeneration are presented. The subject of hardness measurement as a predictor of "in process" abrasion is discussed. The cost/benefit issue of carbon activity level is addressed.

Jan 1, 1986

By Rudolf E. Greuer, Xintan Chang

Mine fires have always been of great concern to mining engineers and their behavior has been studied for a long time. Although an abundance of observations exist, no satisfactory mathematical model for their interpretation and extrapolation has become known. The paper presented here tries to close this gap, making use of the laws of chemical kinetics, energy and momentum conservation. To overcome the mathematical difficulties, the fire zone is axially divided into segments and radially into sections, each one with an extension of only a few inches. Conditions in segments and sections are updated in time intervals of one second or less. To solve the large number of resulting equations, a numerical solution is performed. The model has so far been tried on timber fires. It confirms experimental observations on the ignition phases and equilibria of these fires.

Jan 1, 1987

By A. T. Yu

The broken hill proprietary company Ltd., Australia's only steel producer, has come a long way. Since 1885 to reach today's. Capacity of 6.6 million long tons of ingot steel per year.* its Newcastle steel complex in New South Wales, located 100 miles north of Sydney and on-stream since 1915, has likewise shown continued impressive growth (fig. 1). The most recent expansion plans at Newcastle call for sub¬stantially increasing its production, with the help of some added facilities, but principally relying on the increase in efficiency of the furnace operation. Its modern raw materials blending system will playa major role in meeting Newcastle's new targets.

Jan 1, 1969

By Dr. H. Askew

The input needs of the steady state modelling process are outlined and a methodology for designing a plant survey to meet those needs described.

Jan 1, 1995

By Sigmund J. Sulinski

The following is a progress report on a continuing study being made by the Sanitary District for purposes of developing reliable data for predicting costs and progress on future tunnel contracts. All data available to date on five separate tunnel contracts has been analyzed. All were machine-mined in soft ground, all used steel ribs and wood lagging and finished inside diameters varying from 5'6" to 6'6". Basic data regarding progress per shift, hours mined per shift, hours of downtime per shift, cause of downtime and type of soil mined were reported by the District's resident engineer at the job site. Figure 1, Weekly Mining Report is an example of the form used. Data regarding manpower and equipment used during tunnelling operations was also supplied by the resident engineer during the course of construction. Soil type being mined was verified by the resident engineer during construction, by visual observation, and compared with data listed on a previously prepared soil profile. The soil profile is a graphic presentation of anticipated soil stratas superimposed on a cross section

Jan 1, 1997

By Gordon M. Pugh, David G. Rasmussen

INTRODUCTION Shrinkage stope mining can be employed in steeply dipping veins where both the wall and the vein material are sufficiently strong to stand with only minimal ground support. Shrinkage stope mining takes advantage of the swell in volume produced in breaking in-place ore. This expanded volume of ore is allowed to occupy part of the mined-out vein, and in so doing provides ground sup¬port and a working surface for the miners. Only enough of the ore is drawn after each stoping cut to allow work¬ing room. Not until the entire mining block has been broken is the full amount of broken ore drawn from the stope. DEVELOPMENT PRACTICES FOR SHRINKAGE STOPING The vein is developed into stoping blocks, each of which is 76 to 91 m (250 to 300 ft) in length and 61 m (200 ft) between levels. Level development, described later, is either on the vein or parallel to it with crosscuts periodically driven over to the vein. There are usually two exits from each stope. The first entry is a raise at one end driven either conventionally by raise climber, or by a raised borehole. Present practice is that this raise, put in from level to level, is either a 2.1- x 2.1-m (7- x 7-ft) Alimak raise or a 1.2- to 1.8-m (4- to 6-ft) diam borehole. Either raise system will require pro¬visions for an ore chute carried with the stope to the haulage level or the scram drift. At 9- to 12-m (30- to 40-ft) vertical intervals, dogholes are developed from the raise so that when stoping breaks back into these dogholes, timber or steel sets and necessary service facilities can be installed. The second entry to the stope may be either a similar raise at the stope endline, or more economically, a cribbed raise carried with the stope. As previously stated, development of the ore block is achieved by either drifting on the vein or by paralleling the vein with a footwall lateral and then crosscutting over to the vein at specified intervals. In the following discussion, three basic cases are illustrated in Figs. 1, 2, and 3. In Fig. 1, development is in the footwall by a 3- x 3-m (10- x 10-ft) trackless lateral. A heading is also driven on the ore and taken either full width or driven a standard size and slabbed to the vein width. Approxi¬mately 9-m (30-ft) long crosscuts on 7.6-m (25-ft) cen¬ters are driven from the lateral to the vein. For ease in muck handling they are usually put in on a slant rather than at right angles. A single orepass, located off the lateral and in the center of one stope block, can serve not only that stope, but also one on either side, up to a tramming distance of not more than 137 m (450 ft). Raises are put at the stope endlines on 91-m (300-ft) centers. The back of the vein is shot down and just enough broken material is drawn off to permit access for men to work off the broken ore. Development in Fig. 2 progresses by driving a 3- x 3-m (10- x 10-ft) trackless heading on the footwall side of the vein. The ore block is delineated by raises on 91-m (300-ft) centers. Crosscuts are again driven on 7.6-m (25-ft) centers over to the vein. Approximately four rounds are then taken up to the vein and each round is successively belled out so that all the crosscuts (pockets, in this case) connect. In this development, as opposed to that in Fig. 1 where there were no belled

Jan 1, 1982

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