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By Kenneth L. Schellie

In preplanning the reclamation of a pit or quarry the geology of the site is the name of the game! The planner must know the parameters of the deposit, the quantity and kind of earth materials to be removed, and the amount and nature of the materials to be left behind or wasted as the result of processing the marketable product. With many states and most local jurisdictions requiring reclamation plans prior to the issuance of mining permits, the need for accurate and complete data concerning the geology of the site becomes increasingly important. The producer need only know that marketable materials are available in sufficient quantity to make the mining operation economically feasible-the planner, in order that the land may be reshaped for a useful purpose, must have reasonably precise information as to the dimensions and configurations of the pit or quarry following extraction and the amount and type of materials available on the site (or in some cases offsite as well). Therefore the geology of the site is of major significance in determining the land forms and use capabilities of the property upon completion of the mining process.

Jan 1, 1974

By L. John Minnick

Current developments in using lime and limestone slurries to remove sulfur oxide gases from the stacks of coal- and oil-burning furnaces have established an important need for treatment systems which include adequate disposal of resulting waste materials. The paper briefly outlines the classes of scrubbers which are using lime and limestone and describes the characteristics of the by-product material being produced. Some discussion is also included relating to methods of disposal of the scrubber underflow. Since coal-burning plants also produce fly ash as a waste material, one system developed by the author's company combines this material with the sulfur oxide by-products. The mixture is processed in a manner which converts the waste products into usable materials with acceptable structural and environmental properties. Recent interest in protection of ground waters from heavy-metal leachates has made the fly ash-sulfur oxide system an acceptable means of disposal, because the conversion products have very low permeability and adequately encapsulate soluble salts within the hardened mass. Although only limited information is available on the types and chemical requirements of limestone used in these processes, a few guidelines are presented to indicate the range of materials that can be used with good results.

Jan 1, 1974

By S. Bhamidipati

Abstract. Controlled flow is an aspect often desired in mine ventilation. This is normally obtained by using fans and regulators to achieve the required pressure balance in the system. Preference for a certain network layout of these control devices is influenced by technical as well as legal and economic factors. In this study, a model is developed based on an economic criterion by which an optimum layout of fans and regulators for a controlled flow system can be determined. The concept is analo¬gous to the critical path crashing. However, a linear programming package is used to demonstrate the solution procedure for a hypothetical venti¬lation network.

Jan 1, 1983

By J. D. Miller, C. L. Lin

A PC, image-based, on-line instrument for measuring coarse particle size on a conveyor belt is under development. The hardware and software required to implement such a system are discussed, including the interface for the special image-acquisition hardware. The system concept is given with examples to illustrate the step-by-step procedure for the implementation of image-processing algorithms.

Jan 1, 1994

By H. C. Lautenschlaeger

Let's start with a bit of History. Before the advent of woven wire screen cloth or perforated plate as we know it today, screens or sieves, as they were called, were probably made by the Greeks or Romans around the year 150 B.C. Coarse openings were made from bamboo or other woven reeds or with holes punched in leather hides, while fine openings may have been made using hair from the long tails of horses woven with small openings. The first metallic woven wire screens were probably produced by the Germans in the 15th Century. All of these screening devices were, of course, hand operated. The first records of mechanically driven shaking screens are found in "John Smeathon's Diary of His Journey to the Low-Country" in 1775. He was the English Civil Engineer who built the famous Eddystone Light House and discovered the formula for making hydraulic cements. He described a screen the Dutch were using as a wooden frame on which woven wire was mounted. This box was inclined at an angle and hinged on the lower end. The upper or feed end was equipped with a pulley so they could raise it up, say 5" or 6", and then let it drop abruptly onto a sill or stop plate, thus jarring the material deposited on the woven wire through the openings. Material that was passed over the deck was scooped up and redeposited on the woven wire for rescreening. This was an early form of what is today known as a recirculating load.

Jan 1, 1983

The advantages of quantitative environmental risk assessment techniques over the more commonly used qualitative approach is widely accepted. One important parameter related to the level of risk is the extent and geographic spread of pollutants. Geographic Information Systems (GIS) provide a powerful and highly flexible tool that increases the sophistication of the risk assessment methodology. Through spatial representation, the estimated risk becomes more comprehensive, thus facilitating the decision making process. In addition, valuable qualitative information can be incorporated into the risk assessment procedure with the help of GIS. This paper illustrates a methodology for quantifying risks posed to human health, by exposure to contaminated land, in a manner, which gives a measure of the uncertainty in the assessment and preserves the spatial distribution of the risks. The case study utilised to illustrate the methodology is a large industrial area around a number of decommissioned minerals production and processing sites with known high heavy metal loads at Lavrio, Greece. The spatial distribution of Pb concentration in soils was derived from 425 soil samples collected over a total area of 120 km2. Indicator kriging was used to quantify the spatial distribution of the risk and related uncertainty and the results displayed in map form using GIS.

Jan 1, 2003

By Alfred Weiss, Andrew E. Nevin, Thomas J. Neil, O&apos

As Edward E. Runyan, 1983 AIME President, in an interview excerpt in ME, June, p. 607, stated, "...the AIME Transition Committee has recom¬mended to the AIME Board that each Constituent Society be allowed the option of separate incorporation, whereby each could become its own separate legal entity." Background The American Institute of Mining Engineers (AIME) was formed in 1871 by 22 engineers in Wilkes-Barre, PA. Although originally a mining organization, it became a home for metallurgists, iron and steel industry people, and for the individuals in the expanding petroleum engineering profession. There are now four Constituent Societies: Society of Mining Engineers, located in Littleton, CO, 29,000 members; Society of Petroleum Engineers, located in Dallas, TX, 47,500 members; The Metallurgical Society, located in Warrendale, PA, 10,000 members; and Iron and Steel Society, located in Warrendale, PA, 6,500 members. Each of the four groups has grown and continues to serve the specific and/or diverse needs of its membership. As the needs and requirements of their industries and professions change, each of the Societies has perceived and initiated programs that serve their constituency rather than AIME as a whole. Therefore, each Society has recognized an increasing need for autonomy to better augment their own programs. An AIME Ad Hoc Transition Committee, with Robert Merrill, AIME Past President, as chairman, made a number of recommendations pertaining to AIME operations that were approved in October 1982 by the AIME Board of Directors. One of the recommendations was to endorse separate incorporation of the Constituent Societies on an individual-society-option basis. The AIME Board commissioned a task force of Constituent Society representatives to develop specific revisions to the AIME Certificate of Incorporation and the AIME Constitution and Bylaws. This was done to allow separate incorporation and to reflect the decentralized structure of the Institute. The SME-AIME Board of Directors subsequently approved the recommendation of SME Working Party #69 that SME pursue separate incorporation. Meanwhile, Working Party #69 continues to work with the other Constituent Societies and with the AIME Task Force on Reorganization to determine the form and substance of the separate incorporation. Why Incorporate? George Webster in The Law of Associations quoted Chief Justice Marshall's (1819) definition of corporation as: "A corporation is an artificial being, invisible, intangible, and existing only in contemplation of law. Being the mere creature of law, it possesses only those properties which the charter of its creation confers upon it, either expressly or as incidental to its very existence. These are such as are supposed best calculated to effect the object for which it was created." SME-AIME attorneys, Davis, Graham & Stubbs, have pointed out that the status of an organization operating as an unincorporated association is always unclear. At present, SME-AIME administers assets of almost $3.5 million (mainly property and inventory) but technical ownership and ability to enter into contractual relationships resides with AIME. However, the operation appears to outsiders (particularly those with whom SME-AIME does business) to be an independent operation which would be expected to be a legal entity in its own right. Advantages of Incorporation Liability. Because of legal ownership by AIME of all assets of the Constituent Societies, those assets are subject to the claims of any of the creditors of AIME or any of its constituent parts (i.e., the other societies). Liabilities can be those usually encountered in business but also encompass special risks, which could develop if there were a careless and erroneous publication of material that might be used in practice or if standards are improperly established. The recent US Supreme Court decision in American Society of Mechanical Engineers, Inc.,

Jan 10, 1983

By V. Karra

Based on extensive investigations on the effect of design variables on process performance, during 1982-85, Nordberg developed a 1000 hp cone crusher, with the objective of boosting crushing productivity in existing plants. The 2390 fits on the same foundation as the 7' SHD Symons cone, but is designed to give two times the capacity of the 7'. The economies of scale involved give the customer substantial cost savings. In this paper process performance of the Nordberg 2390 relative to the 7' SHD Symons cone, while crushing the same ore, will be presented. Also, implications of such a crusher scale-up to associated cost savings will be addressed.

Jan 1, 1988

By Peter Maltby

A $20M pressure oxidation facility is under construction at the Nerco Con Mine, Yellowknife. Plant commissioning will start in the third quarter of 1992. Roasting of arsenical auriferous concentrates prior to 1970 left 45,000 tons each of highly toxic gold-bearing arsenic trioxide sludge and roaster calcine at the minesite. Safe disposal of these wastes has been a high priority. In 1983 an arsenic trioxide plant was built by the former owner to re-treat the sludge and to sell the product. Due to a poor market and high operating losses, the plant was closed by Nerco in 1989. Mine production in the future will revert increasingly to refractory ore as a replacement for free-milling ore which has been the mill feed since the roaster was shut down. With this fact in mind, Nerco management saw the potential of a proven process to recover the gold from a combined feedstock of refractory flotation concentrate, sludge, and calcine waste. A further requirement was the stabilization of all the arsenic as an insoluble ferric arsenate. By the end of 1989, after the completion of a literature search and a study of process economics, pressure oxidation was selected. Extensive bench and pilot plant work was completed in 1990 and early 1991 to develop the process parameters and to complete environmental testing of the autoclave products. Management approval for construction of a pressure oxidation facility was made in December 1990. Plant capacity is 96 tpd requiring a 40 tpd VSA oxygen plant on site. Detailed engineering began in March 1991. The pressure oxidation building was completed by the end of 1991. The autoclave arrived on site and was mounted on its foundation in December 1991.

Jan 1, 1992

By D. Royston

A novel low-cost technology is described that treats excavation waters in estuarine environments where water coloration due to humic material is present, along with acidity, turbidity, sediment and salinity. The process treats all the components in the water to produce a clear (color-free) water stream that meets requirements for direct discharge to local estuarine waterways.

Jan 1, 2003

By J. D. Mc Beth

The Carlin Gold Mining Company, a wholly owned subsidiary of Newmont Mining Corporation has been successfully operating an open pit gold mine and cyanide mill for approximately the past ten years. It is a unique operation in that about 20 percent of the mill feed is a carbonaceous ore refractory to cyanidation that must undergo a pretreatment stage developed for, and by, Carlin. The mine and plant are located in the Tuscarora mountain range is north-eastern Nevada near the towns of Carlin and Elko. Claims were staked at the minesite in 1961 and 1962. A drilling program was initiated late in 1962 and after drilling a total of 250,000 feet of rotary drill holes an estimated 9,300,000 tons of ore at a grade of 0.32 ounces of gold per ton was delineated.

Jan 1, 1975

By E. B. Jensen

The results of an extensive one- year test period of a nonelectric explosives detonating system led to the mine-wide adoption of this system at the Henderson Mine in early 1978. Since that time, extensive experience with nonelectric initiation has verified the earlier results which include the following benefits: 1. Increased blasting safety 2. Improved productivity 3. Cost effectiveness 4. High reliability At the present time, while electric blasting caps still experience a limited use restricted to trunkline initiation, all heading rounds as well as the longhole bell, undercut, boundary cutoff and raise blasting are detonated non-electrically. The primary blasting agent used is AN/FO, and primers are typically one of the following products (depending on application): PETN, semi-gelatin dynamites or a nonnitroglycerin water-gel slurry.

Jan 1, 1982

By L. E. Bowman

Efficient filtration of fine kaolin particles plays a crucial role in processing of raw kaolin to a marketable product. Oftentimes, filtration Is the rate controlling step of the whole process. As a consequence, plant production is dependent, to a great extent, on the rates being achieved In filtration. In order to alleviate the bottleneck in production, Nalco Chemical Company initiated a reagent development program to chemically enhance the performance of the filtration units. Filler aids of different classes were synthesized for evaluation. These include reagents whose primary mode of functionality were: coagulation, flocculation, thickening, and combinations of the preceding. All reagents that were synthesized and tested were listed under the appropriate Food and Drug Administration sections of the Code of Federal Regulations. This paper discusses the development and application of a new reagent that Improves the filter production rate with minimal Impact on filter solids. The results of laboratory filter studies along with plant data are presented and discussed. Plant data indicate that this reagent is capable of increasing production rates by as much as 35% on various clays of coarse particles to the finest fractions, as well as clays that are calcined. The reagent's Impact on solids content, re-slurrying characteristics, Brookfield and Hercules viscosity, and drying is within the standards set by plants who have evaluated and now use this product.

Jan 1, 1993

By William M. Phillips

This paper will concern the processing of kaolin clays from the sedimentary deposits of Georgia and South Carolina, While the major processing steps will be touched on briefly, emphasis will be given to the dewatering of the clay-water slurries (slips) formed in the processing of kaolin clays The dewatering steps discussed will include gravity settling, centrifugal dewatering, vacuum filtration, and thermal dryings Of these dewatering steps particular attention will be given to vacuum filtration and the variables affecting filtration of these kaolin clays.

Jan 1, 1962

By N. Duru

"Gravity concentration is still a challenging area in the mineral industry. This is mainly because of the fine size valuable mineral losses to the tailings during its application. But the recent developments in centrifugal separation methods and their mutual application with conventional separation techniques has increased mineral recoveries. In this paper, field application of conventional gravity separation methods with the combination of 2” diameter hydrocyclone cluster unit and a multi gravity separator (MGS) was discussed. Additionally, particle size distribution and chromite content of the plant streams is presented and initial laboratory test results were compared with the actual plant data throughout the paper. As expected, field data showed derivations from the laboratory tests but the combination of MGS and conventional gravity separation techniques resulted in gravity separation of -0.1 mm chromite particles. INTRODUCTION The purpose of this mineral processing plant project was to investigate the possibility of upgrading chromite ore from 12% to 48% Cr2O3 and having final tailings assay as 2% Cr2O3. For this reason, initially a set of laboratory gravity separation studies were conducted to evaluate the performance of combination of 2” diameter hydrocyclone cluster and multigravity separator. After obtaining successful results from the laboratory work, a feasibility study was initiated. Economical results of the feasibility study showed that an achievable high net present and return on investment values. Following the investment decision; engineering, equipment procurement, construction of the processing plant was completed in eighteen months. This paper focuses on the initial laboratory test work results, operational data of the 2” diameter hydrocyclones and MGS units; resulted chromite recoveries. Processed ore has the chromite associated with serpentine and olivine minerals. The chromite particles are generally in round shapes with sizes between 50 µm to 1600 µm and average size of 450 µm. The microscope images of the chromite and associated formations are presented on Figure 1.Chromite is formed in mixture with iron oxides, with varying amounts of magnesium, aluminum. The average chemical composition of the representative drill core samples of the ore deposit is given on Table 1."

Jan 1, 2017

By W. L. Fourney, D. C. Holloway, J. W. Dally

Introduction Improvements in the process of rock excavation by blasting involves better control of one or more phases of the fracture process immediately after detonating the ex- plosive charge. Total control of the process involves individual control of (1) The number of fracture planes. (2) The crack initiation sites. (3) The direction of crack propagation (usually radial). (4) The stress field driving the fracture front. Fracture plane control is usually accomplished today by using the smooth wall blasting method; however, investigations by the authors (1) indicate several areas where this method could be improved. These improvements include: a) generation of stress concentration factors at the location of the initiation sites; b) protection of the remaining region of the borehole wall to inhibit initiation of any cracks not associated with the fracture plane and fragmentation pattern; c) limit peak detonation pressures to avoid borehole crushing and maintain by stemming residual gas pressure in the bore- hole during the crack propagation period. This paper describes experiments con- ducted with a charge holding device fabricated from thin-wall steel tubing which was partially slit at fracture locations. The tube lined the bore-hole in laboratory tests to simulate smooth wall blasting. Results showed close control could be achieved relative to both the number and the location of the fracture initiation sites.

Jan 1, 1977

By L. G. Austin

The data of Dunn and Martin (1978) is reanalyzed using a rigorous application of Hertzian theory to the impact process. The Young's modulus of steel required to fit their data to the theory is a factor of about 10 3, too low compared to the values quoted for steels. Thus, doubt is thrown on the validity of their experimental technique, and it is possible that their values for maximum impact force and stress are far too low.

Jan 1, 2002

By Shouci Lu, Keji Sun, Dianzuo Wang, Yiqun Li, Chuang Jin

The dephosphorization of iron ore and reduction in Fe loss in process are currently the foremost technological challenges facing the mineral industry of Meishan Iron Ore. These problems can be resolved to a greater extent by an apatite flotation process which depends on selective flotation reagents. The primary objective of this research work is to develop new type of flotation collectors for dephosphorization of weak magnetic iron ore. Detailed discussion is given on the influence of collector dosage, pH, dispersants and pulp temperature on the flotability of apatite, siderite and hematite using the collectors of Oleyl sarcosinate(OSS), Alkyl polyoxyethylene ether phosphate (AEP) and the mixtures of OSS and AEP A key feature of the flotation was the use of the mixtures of OSS and AEP as a selective collector for phosphate. The effects of chemicals and operational variables on the phosphorus flotation from the weak magnetic iron ores have been investigated. The test results shows that floating the phosphorus minerals with new type collectors can reduce the phosphorous content in the flotation concentrate to an acceptable level of less than 0.20% P with increased Fe recovery.

Jan 1, 2002

By Mel J. Laurila

The application of on-line ash analyzers in coal processing has become widespread. However, the analyzers are employed largely in monitoring, blending or sorting applications. Just recently has work begun on using on-line ash, moisture and/or solids data for plant control; and even more recently for localized circuit or unit operation control. Process Technology, Inc. (PTI) has since 1990 placed several bulk coal and slurry analyzers in practice where Fuzzy Logic Control (FLC) loops are used to manipulate controllable variables in real time. This technology is now being advanced by PTI. Unit operations where FLC has been employed in feedback loops using on-line ash analyzers include: heavy media vessels, cyclones, concentrating tables and froth flotation. The design, implementation and improvements attainable in preparation plant control using on-line ash analyzers are outlined in this paper.

Jan 1, 1995

By Tetsuji Hirato, A. J. Monhemius, Yasuhiro Awakura, G. W. Warren, E. Peters

An electrostatic pseudo-liquid membrane technique, in which extraction and stripping take place simultaneously in a single reaction vessel using an electrostatic dispersion, was applied to recover Ni(II) from aqueous 0.1 kg m-3 Ni(II)(as NiSO4) – CH3COONa solutions, and the Ni(II) ions were concentrated by a factor of 9 into an aqueous 1.0 kmol m-3 HCI solution using D2EHPA as an extractant at the applied voltage of 3.7 kV for the dispersion. When the process of ESPLIM proceeds favorably, the concentration of Ni(II) in the upper part of the organic phase of the reaction vessel is lower than that in the lower part. In addition, the concentration of Ni(II) in the organic phase of the extraction chamber is higher than that in the stripping chamber. For the stable operation of this process, the stripping rate must be greater than the extraction rate to prevent the excess accumulation of Ni(II) in the organic phase which leads to the poor dispersion of the aqueous phase.

Jan 1, 1993