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By J. Platt

Recent EPRI research on utilities? likely strategies to reduce sulfur emissions differs sharply from policy analyses showing all- switching or all-scrubbing choices. Energy Ventures Analysis, with Stearns-Catalytic and A. T. Kearney, estimated sulfur-removal costs for scrubbing or switching at virtually all affected plants in the 31 Eastern States. Cost tradeoffs occur between $30 and $40-plus per ton FOB mine in Central Appalachia ($33-44-plus per tonne). 1/2 to 3/4 of total sulfur reductions comes from scrubbing, whose costs act as a cap on low-sulfur coal prices. In a severe environmental scenario, low- sulfur coal demand evaporates, replaced by very low-sulfur (0.7%) coal demand. Additional findings and implications of EPRI coal supply and market studies will be reviewed.

Jan 1, 1987

By Armine F. Banfield

The Purpose of the Paper It is fitting that the first paper of a session on the Financial Aspects of Mining should be on the basic data upon which any financial discussion of a mining project must be based. The history of a mining project starts with exploration in an area considered geologically favorable for mineralization and culminates in the discovery of a body of valuable mineral material commonly known as a mineral deposit. Subsequently more detailed exploration establishes the approximate size, shape, tonnage and average grade of the deposit by surface and/or underground drilling, -surface trenching and/or underground workings. Some preliminary metallurgical testing and other studies, as required, are made at this time. Development work is then carried out to provide representative samples for determining flowsheet and metallurgical balances, preparing the deposit for production and establishing more firmly the grade and mining characteristics of the deposit. A feasibility study is then made of the engineering aspects of the project including the estimation of operating coats, the capital required to place the deposit into production, profit and return on investment. A valuation of the deposit

Jan 1, 1972

Improvements in computer technology and associated software have allowed the improvement and development of more advanced ventilation modeling software packages including those that have the ability to simulate the effects of a mine fire on the ventilation system in terms of heat, smoke and gas distribution. This ability has real applications for the mining industry in terms of emergency planning, training and response. The primary focus of this paper will be the benefits to training programs that this type of software can provide to all types of training for various personnel, from the newly hired inexperienced miner, mine rescue, atmospheric monitoring personnel and emergency evacuation drills. The results of the simulations can then be used to give miner?s more detailed information on what types of conditions they may face based on the type and location of the fire and the program itself can be used to manipulate the ventilation system in a way that emergency response personnel may (i.e. tear down stoppings to reduce airflow to the fire area) and see the effects in real-time.

Jan 1, 2012

By S. Mohanan, C. R. Kumar, S. K. Bhoja, T. Venugopalan

"A pressing issue that has often been the topic of discussion in iron-making operations in India is the high content of alumina in the country’s iron ore deposits. The presence of alumina has hampered production by affecting slag fluidity, and thereby the hot metal quality. Iron ores from Indian mines are generally rich in hematite, with traces or small amounts of goethite/limonite, kaolinite, gibbsite and quartz reported from time to time. In day-to-day production, emphasis is placed on checking the chemical analysis of product samples, but the true solution to the alumina problem lies in estimating the mineralogy of the ore samples. We developed a mathematical model, based on singular value decomposition, to predict mineralogy from classical chemical analysis. We then used X-ray diffraction patterns, scanning electron microscope analysis, and grain counting with an optical microscope to determine actual mineral compositions and to test the values predicted by the model. The results indicate that with regular calibration, the model can be used as a simple, fast and effective tool to predict on a regular basis the mineralogy of multiple samples.IntroductionIndian blast furnaces use high-grade iron ores (as lumps or as sinter) and coke (obtained from the destructive distillation of coal) as raw materials for the production of high-quality hot metal to be converted into different steel products through the Linz- Donawitz process. The iron ores are mainly sourced from the Singhbhum region of Odisha and Jharkhand states, the Bailadialla region of Chattisgarh state and the Bellary region of Karnataka and Goa states, and are mainly classified based on size as (1) lump ore (fed directly into blast furnaces), (2) fines (converted into sinter/pellets and fed to blast furnaces) and (3) slimes (< 0.15 mm; currently dumped in huge slime ponds). Any variation in the quality of the ores supplied results in variations in the production trends of hot metal."

Jan 1, 2015

By R. Mensah-Biney

The aqueous biphase separation process (ABS) has been used to separate ultrafine industrial minerals. The partition behavior of TiO2, Al2O3, Fe2O3 and kaolin was not pH dependent. The partition behavior of SiO2 was, however, pH dependent. The partition coefficient of kaolin in PEG 3400/ Na2CO3 biphase system was = 150 and that of the silica in the same system was = 0.02, resulting in a separation factor of = 8500 between kaolin and silica. The aqueous biphase separation system was used to separate free silica from kaolin in a raw clay sample from Mexico. The partition behavior of mica, feldspar and clay from North Carolina was also evaluated.

Jan 1, 1999

By Kyle Kittle, Kyle Knaeble, Albert Ruiz, Gregory Raines, Ryan Gewargis

The Chimney Hollow Reservoir Project (CHRP) is located southwest of Loveland, Colorado. CHRP is a component of the Windy Gap Firming Project, operated by the Municipal Subdistrict of the Northern Colorado Water Conservancy District. The inlet/outlet tunnel (IOT) for CHRP contains a reinforced concrete lined alve Chamber with PC membrane waterproong that was ecavated via seuential ecavation method to a diameter of feet. The IOT was ecavated using both drill and blast and road header with ground support consisting of steel sets, rock bolts, wire mesh and shotcrete. The IOT will withstand 300 feet of water head and rock ll surcharge load from the dam embankment constructed over the tunnel.

Jun 23, 2024

By Boyd Eisenbraun, Dennis Murr, Milton Rojas

Approximately since 1925, the phenomena of grinding and classification of minerals with screens have been studied. In the U.S. iron ore mining operations located in the so-called “Mesabi Iron range,” magnetite processing plants have made progress in the application of high-frequency screens that have allowed them to process low-grade Taconite ores and successfully achieve the economic benefit of these minerals. In the particular case of magnetite minerals disseminated in the siliceous matrix, the main objective is to reduce the generation of particles called “middlings” with high silica contents. Commonly the primary challenge of the metallurgical task is to achieve high recoveries and iron concentrates with low impurities. To achieve this, several studies and industrial applications have shown success in this regard and not only in iron ores, but also in other minerals around the world. The study described in this paper attempts to describe some key aspects that helped develop an effective solution and list the benefits associated with this modern process design by using industry-proven technologies for minerals in Chile that have similar characteristics to the minerals of the iron belt in the United States.

Feb 1, 2025

By J. C. Haptonstall

Stoping methods at the Homestake Gold Mine through 1978 had been traditional overhand cut-and-fill, shrinkage or square set. High costs, low-productivity and safety concerns prompted the mine to search for and adopt a "bulk mining" technique as a primary stoping method. Blasthole stoping had been successful but it is very development intensive, and was not suitable for the mine&apos;s accelerated mining program. Vertical Crater Retreat stoping was selected, and today accounts for over 50% of ore production. Case histories representing both the successes and failures of VCR stoping in the mine are discussed.

Jan 1, 1986

By Satya Harpalani

The four most important parameters controlling the flow of gas in coal are the gas content, permeability, diffusion coefficient and cleat characteristics. Estimates of these and, more importantly, a knowledge about the variation in their values over time are required for simulation of long-term gas production. This paper describes experimental techniques to determine each of these, along with their time dependency, under simulated in situ conditions. It is shown that the permeability, diffusion coefficient and the cleat aperture values are not constant as usually assumed to be. There is a significant variation in their values as a result of changes in the microstructure of coal associated with release and flow of gas.

Jan 1, 1995

By Leonard N. Hill

Cyprus Sierrita Corp. has 16 parallel 5.03 m-diam x 5.8 m long (16.5 ft-diam x 19 ft) primary ball mills, each operating in closed circuit with a nest of cyclones. Before the upgrade to 840 mm (33 in.) cyclones, each mill operated with a nest of five 660 mm (26 in.) cyclones - four in use and one on standby. In this configuration, the mill throughput was 88.5 kt/d (97,500 stpd). Flotation feed averaged 25.9% +212 pm (+65 mesh). The 660 mm (26 in.) cyclones normally operated at an inlet pressure of 34 kPa (5 psi), lower than the inlet pressure of 55 kPa (8 psi) recommended by the manufacturer. The circuit was typically operated with cyclone overflow densities greater than 40% solids to achieve the required throughput. This resulted in inefficient cyclone operation and excessive coarse oversize reporting to flotation. The apexes choked frequently. Larger apexes were tested but reduced the classification efficiency and resulted in circulating loads greater than 800%.

Jan 1, 1994

By Cody Giroux, Homer Scurlock, Michel Wasag

Silica and Crystalline Quartz exposure continues to be a serious health threat to nearly 2 million workers in the United States, including more than 100,000 working in high risk jobs such as abrasive blasting, foundry work, stonecutting, rock drilling, quarry work, mining and tunneling. The primary focus of this study is to identify the best methodology to reduce particulate-laden air and limit/eliminate exposure to respirable dust with silica/crystalline quartz during tunneling operations. This study focuses on two de-dusting systems employed on similar tunnel construction projects. The first project is the Coxwell Bypass Tunnel located in Toronto, Ontario Canada. The second project is the Westerly Storage Tunnel located in Cleveland, Ohio. The Toronto project is utilizing a wet de-dusting system. The Cleveland project is using a dry de-dusting system. The objective is to determine which system provides the best protection and suitability to capture, remove and ultimately reduce respirable concentrations of silica/ crystalline quartz to safety and healthy levels in underground tunneling activities.

Jun 13, 2021

By W. K. Katoto

The Tailings Leach Plant (TLP) of the Zambia Consolidated Copper Mines Ltd at Nchanga was commissioned in 1974 as the world&apos;s first largest successfully operated agitation leach SX-EW plant for copper production. The design, development and operation of the plant soon after commissioning termed as TLP stage II has been described by Holmes et al (1). In the initial phase the plant was designed to treat approximately 25,000 tonnes per day of current flotation tailings from the Nchanga Concentrator operations, and had a design capacity to produce 75,000 tonnes per annum of copper. Further expansion took place in 1986, and TLP stage III was successfully commissioned to treat an additional 20,000 -25,000 tonnes per day of large reserves (over 135m tonnes) of reclaimed tailings stockpiled since the early 1930&apos;s in four paddock type tailings dams (T01 to T04). The salient feature of TLP stage III expansion described by S K Mwenechanya et al (2 -3) was the installation of the world&apos;s largest Horizontal Belt Filter Plant with 26 filters each of 80 m2 filtration area.

Jan 1, 1996

By G. L. Mowrey

One critical element of the U.S. Bureau of Mines (Bureau) autonomous mining research program is the development of a reliable coal interface detection (CID) system. Several candidate CID concepts currently being investigated by the Bureau include vibration, passive infrared, radar, and natural gamma radiation (NGR). To establish which CID sensor technologies need to be developed for a given seam, coal and adjacent rock samples (i.e., immediate roof and floor) are being collected from selected major coal seams in the U.S. and are being analyzed in terms of NGR and other geophysical measurements. Results of the NGR measurements indicate that, in general, all shale and shale-like materials (e.g., drawslate, slate, and fireclay) have higher NGR readings than the coal seam. Consequently the NGR method appears to be a potentially useful CID tool, provided that the immediate roof and floor are both composed of a high percentage of shale-type material.

Jan 1, 1990

By James E. Lawver

During 1981 the Florida phosphate industry produced more than 43 million metric tons of phosphate rock - about one-third of the entire world production and also generated nearly an equal amount of waste clay and waste clay-sized product that requires dewatering and disposal. The material balance of solids and water for a typical Florida phosphate mining operation is shown in Figure 1. Historically, the industry has impounded clay waste (about 60% below ground and 40% above ground) in earthen dams, often as large as 800 acres and occasionally greater than 60 ft. high. The dams have served the triple purpose of: 1. Dewatering initial 3% solid waste clay for process water re-use. 2. A reservoir system to minimize water discharge from the mining area and to capture and store rainwater thus minimizing deep well pumping requirements. 3. The ultimate densification and storage of waste clay.

Jan 1, 1983

By M. Pope

By 1950, packaged oil and gas fired boilers were on the market for capacities up to 30,000 lbs./hr. By 1962, capacities were up to 100,000 lbs./hr. and even higher when separate heat traps (economizers and air preheaters) were attached to the boiler packages. During this period, complete packaged coal fired boilers were developed into the 10-15,000 lbs./hr. range. Oil and gas fired plant designs became very compact, "basementless", and far: less costly than the coal fired plants of any capacity. Coal fired plants remained large and expensive, required field erection of boilers and required basements. With the spectacular strides made in automation, oil and gas plants became far less costly to operate, requiring only the part-time attendance of a single operator. Some advances were made in coal fired plants, but not to the degree attained by the fluid fuel competition.

Jan 1, 1965

By R. W. Waytulonis

This paper is an update of the activities of the U.S. Bureau of Mines, other government agencies, and the automotive and truck industry concerning diesel emission control. Enacted and proposed regulations from the U.S. Mine Safety and Health Administration (MSHA) and developments in diesel emission control are presented in terms of their impact on underground coal, metal, and nonmetal mines. Mine air quality regulations proposed by MSHA may require the underground mining industry to comply with new standards. Some mines may be required to take additional actions to meet new diesel particulate and lower nitrogen dioxide exposure standards; however, the mining industry is in a position to benefit from emission controls developed for the on-highway diesel engine market. The U.S. Environmental Protection Agency (EPA) has enacted regulations to reduce emissions from on-highway diesel trucks and buses. Engine manufacturers have responded by developing cleaner burning engines. Fuel producers have responded by providing cleaner burning reformulated diesel fuel, and exhaust aftertreatment devices have been developed to provide additional emissions reductions. Bureau research and development projects seek to determine the advantages of using modern engines and fuels, and to evaluate the efficacy of new exhaust control devices on mining machines. It appears that the diesel engine will continue to be a practical power source for use in confined environments because no other available power source is as mobile and efficient.

Jan 1, 1993

By Ahmet Tezcan, Zeki M. Dogan, Yalçin Kaytaz

Autogenous grinding in Turkey was first applied to quartzite where the mill is grate discharge type with an internal diameter of 2.99 m, having a length of 3.20 m and a capacity of as to 11.0 tons per hour. The second autogenous grinding was applied to a copper ore at Murgul Cakmakkaya Flotation plant of (KBI) Black Sea Copper Works having three mills 26 feet in diameter and 10 feet in length in close circuit with hydrocyclones. Recently, alterations were made in grinding circust by adding pebble mills. Furthermore, rubber liners and lifter bars were introduced pebble extractor and classifier were new features in the primary mills and circulating load was reduced by 20-50 tons per hour. At the end of these charges, capacity of each mill line was increased to 48 tons per hour with a full capacity of more than 9000 tons per day. Thirdly, autogenous grinding has been executed successfully on the slags of Samsun Smelting Plant of (KBI) Black Sea Copper Works with a mill of 20 feet in diameter and 6 feet on length having pebble mill following autogenous grinding.

Jan 1, 1992

By Mostafa Benzaazoua, Bruno Bussière, Mukendi Kongolo

The desulphurization process has been proposed over the last few years for acid mine drainage control at certain mines, which generate low to medium grade sulphidic tailings (-3 to +25 wt% S). The environmental sulphur recovery, which means the sulphur to be floated to produce a non-acid generating final tailings, depends mainly on the intrinsic neutralizing potential of the tailings. However, in some cases the sulphur cleaning is complicated by other parameters which affect the flotation probability of the sulphide particles. In this study, a number of tests were conducted with a Hallimond tube and Denver Cell on both pure mineral and mine tailings. To develop a better understanding of the mechanisms of non-selective sulphide flotation, three types of approach were investigated in this work: (i) pure pyrite at progressive milling degrees, (ii) artificial mix of pyrite and quartz at different calibrated granulometry and (iii) same composition tailings with 26 % wt sulphur at progressive milling degrees. The effect of the granulometry on the sulphide flotation was demonstrated both. The results allow us to define a granulometry model, which can then be considered in the whole desulphurization modeling.

Jan 1, 2000

By Edmund C. Bitzer

The unit costs of dry crushing, within the efficient reduction ranges of equipment now available, are considerably less than those for the reduction of the same material in the same size range by wet mills using grinding media. This is a commonly recognized fact which cannot be disputed; still we find considerable imbalance in costs between the crushing and grinding sections of many operating mills. In other words, there are many instances where more reduction could be accomplished in the lower cost area of dry crushing. In addition, equipment is now available which enlarges this area and makes it possible to consider much finer crushing than has been heretofore economically feasible. There has been a tendency for the past two decades to utilize wet rod-¬milling in the reduction step. This actually amounts to a fourth stage of crushing in a size range formerly served by roll crushers which have fallen from favor on account of high operating costs, Some investigations have indicated that there is not sufficient difference in the operating costs of rolls and rod-mills to give a clear cut advantage to either method, There has for some time been a need and an opportunity for a dry crushing process to improve costs in the range now served by these two systems.

Jan 1, 1965

By Robert T. DeGavre

I have been asked by the Society of Mining Engineers to present a paper on Inco Limited&apos;s Indonesian nickel project as a case study in the financing of large overseas mining projects. I welcome this opportunity It is a story worth telling not only because the project itself represents a significant human achievement but also because there are certain important lessons that can be derived from our experience in financing the project. The paper will be divided into four sections: (i) a brief history of the project, (ii) a critical appraisal of the project&apos;s financing plan in terms of the goals that we sought to achieve, (iii) some comments on certain factors underlying the relative success of the financing plan, and (iv) the contributions that the engineering staffs must make to a successful financing plan. The paper will not present a technical assessment of the project since Inco Limited has been asked to submit a series of papers on this subject at the International Laterite Symposium as part of the 108th Annual Meeting of the AIME in February 1979.

Jan 1, 1978