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By S. K. Kawatra

It has been observed in some mineral processing plants that grinding circuit efficiency varies seasonally, such as in some plants which are located in the northern U. S. and Canada and undergo large seasonal temperature changes, with the grinding circuit efficiency different between summer and winter. This indicates that the temperature of grinding circuit slurry has a noticeable effect on grinding performance. The effect has rarely been studied. To this end, an investigation to examine the effects of changing temperature on efficiency and determination of the mechanism responsible has been carried out. Plant investigations and laboratory experiments have been conducted in order to study hydrocyclones. It was demonstrated that under otherwise constant operating conditions, the d50(c), size decreased linearly with increasing temperature, while the shape of the reduced efficiency curve remained constant. This effect was determined to be due to changes in slurry viscosity with temperature.

Jan 1, 1988

By N. J. Themelis, W. H. Dresher

Research is probably the least understood and the most underrated or overrated, depending on the circumstances, function of the corporate enterprise. Some companies become engaged in research because they consider it to be vital to their very existence, others in order to develop new business, and some with no clearer objective than to keep up with the competition. Whole new industries have resulted from research activities, such as the Xerox copier, the transistor, the computer, and have affected considerably our way of life. Companies have prospered or perished by pursuing the successes or failures of their research organizations. However. despite the tremendous effect that research has had on our modern civilization and the billions which are spent on it annually, we have not as yet been able to develop many hard and fast rules as to how to conduct it effectively and to a successful end.1 This section discusses the role of research in the United States and in the mineral industry and describes a few of the criteria and guidelines which have been developed to assist in increasing the probability for success in industrial research. Broadly speaking, the purpose of industrial research is to make a significant contribution to the long-term viability and the profitability of the sponsoring company. The sum total of technological developments has been a principal factor in establishing the United States as a world leader and the controlling element in the nation's balance of trade with foreign powers. The international aspect of most mineral commodities is a significant factor in the business decision-making of most domestic mining companies and should be an important factor in the operation of research and development (R & D) programs in these companies. The National Science Board has reported that in recent yean other nations have been gaining on the United States over practically the entire range of science. 2,3 On the positive side, the NSB reported a strong position for the US in the results derived from its investment in R & D. If the United States is to maintain a favorable trade balance, it must create new know-how through technological innovation in order to create new industrial products, processes, and services for which there is a global demand. As expressed by Chauncey Starr, president of the Electric Power Research Institute, "Unlike resources found in nature, technology is a man-made resource whose abundance can be continuously increased, and whose importance in determining the world's future is also increasing."' In recent years, the greatly in- creased pressures for environmental quality and energy conservation have enhanced further the role of technical innovation in insuring the future survival of the domestic industry. Technology is the challenge of American industry, and it is a challenge which the mineral industry must also accept, for processed minerals are the very raw materials and energy on which all of industry is based, it is technology which makes a mineral deposit into an ore reserve. The Natural of Industrial R D Research is usually thought of as being either basic or applied. Basic or fundamental research is the quest for knowledge and need not have any practical objective. Applied research is the search for a solution to a particular problem and therefore has a specific objective beyond the acquisition of new knowledge. Development is the next stage to the applied research experimentation and it generally consists of larger-scale tests to establish the technical and economic feasibility of the new process or product and to provide design information for its industrial implementation. The terms research and development are usually interconnected for the good reason that in many cases it is difficult to define where one ends and the other begins. For instance, in many cases, thermodynamic, kinetic, corrosion, and other research studies, which are needed to provide design data for an industrial plant, may prod in parallel with the pilot plant activities preparatory for this plant in order to conserve time. Often the final stages of a development project may involve the trial production of a new product for markeing tests or the trial operation of a new process on a "semi-industrial" scale pilot plant. Such operations may be termed "demonstrations"; hence, more

Jan 1, 1985

By Yoshiaki Numata

It is a matter of importance to use the lower alkyl monoethers of propylene glycol (polyPGME) as a frother in sulfide mineral flotation, for their compounds are highly soluble in water and are surface active frothers to some extent. The purpose of this study is to clarify fundamental roles of frothers in sulfide mineral flotation by investigating the effects of polyPGME on the floatability of galena with xanthate and adsorption property those ethers at the liquid/air interface. Fundamental investigation on the flotation of sulfide minerals using o,o-dialkyl dithiophosphates has been carried out through galena floatability tests in the following two cases:(l)single use of dithiophosphate for sulfide mineral collection and (2) joint use of dithiophosphates for its collection.

Jan 1, 1991

By M. E. Kuchta

Surface coal mine design can be facilitated with the use of an interactive graphics personal computer program. This mineral inventory and planning program (POLY CALC) is described and its use is illustrated with a case study. The case study deals with investigating a stripping sequence and associated dragline stripping requirements.

Jan 1, 1986

By D. Spitty

Mining companies often have many disparate systems and repositories of data in their organization for planning and scheduling outbound mining supply chains. To optimize ore quality, throughput, transport logistics scheduling and delivery to contract, planning teams need to model and manage the value chain accurately and achieve a consolidated, enterprise view of operational performance. Planning teams coordinate a complex series of activities to ensure production forecast accuracy. They also negotiate and execute complex contracts often with disconnected and limited visibility of production forecasts, quality, and variability with little ability to accurately market potential product specifications over longer time horizons. This market is becoming increasingly dynamic, with increasing variability and the time for planning teams to react is decreasing. This is driving the need towards using science to generate the necessary scenarios required to support the decisions made by planners on a frequent basis. Resource-to-Market is a highly flexible, user-configurable supply chain management system for the mining and metal processing industries. This provides an integrated view of the supply chain that supports the dynamic nature of planning in a mining company, embraces variability of elements across the supply chain with the ability to optimize across all the functional areas of the operation to enable optimal decision making for often competing objectives such as throughput, quality, cost, revenue and profit.

Feb 23, 2014

By Richard C. Neavel

Among the many compositional parameters used to judge the quality of a steam coal is the fouling factor of Attig and Duzy1 [% base in ash % acid in ash X % Na20] in ash. The higher the fouling factor, the more likely the heat transfer surfaces of the boiler will acquire a deleterious deposit of sintered ash. While examining the elemental composition of ash from various size and gravity fractions of coals from Illinois, we noticed that variations in the fouling factor were attributable mostly to variations in the sodium content. Further, sodium content was essentially the same in all sink-float fractions from a given coal. In other words, sodium was related neither to the ash nor to the organic material. We therefore concluded that the sodium was most likely in the pore water, which was approximately a constant proportion of all fractions. This led to the supposition that the sodium might be removable through water extraction. This supposition tended to confirm the observations of Daybell,2 Daybell and Gillham,3 and Gluskoter and Ruch4 that much of the sodium in coals existed as water soluble sodium ions. In passing, it should be noted that most sodium in Western U.S. coals (i.e., Wyoming, North Dakota, Montana) is not water soluble, but rather is fairly strongly held in association with the organic material (ion-exchanged).5 Because data reported in the literature were not very conclusive about the typical proportions of sodium that might be removed by water extraction, and because there were few data indicating extraction rates, and finally, because our calculations showed a favorable economic incentive to lower sodium contents, we initiated an experimental program to investigate water extraction of sodium from Illinois coals.

Jan 1, 1976

By Kadri Dağdelen, Matthew Deutsch, Thys Johnson

Nested pit analysis in open-pit long range mine planning is used to define approximate ultimate pit limits and an initial high-level schedule in the early stages of a project. Modern ultimate pit optimizers can solve for dozens, or even hundreds, of nested pits however often a smaller subset of pits which are evenly spaced with respect to contained tonnage are desired for downstream analysis. In situations where that pushback selection process must be automated, such as when performing sensitivity analysis, or when the best subset of pushbacks is required; an optimization procedure is warranted. This paper describes a dynamic programming algorithm for selecting pushbacks following nested pit analysis, which is performant and addresses a long-standing inconvenience faced by long range open-pit mine planners.

Jun 25, 2023

By Preston McGrain

Geologic maps are indispensable tools in the modern search for mineral and fossil-fuel resources. They are the first essential step in understanding the lithologic nature and structure of rock units that form the land surface and that lie beneath it. They provide the basic foundation for planning mineral resource exploration programs and form the superstructure from which subsurface investigations are projected. In view of the economic application of such maps, the Commonwealth of Kentucky and the Federal Government entered a formal agreement in 1960 to map Kentucky geologically on a scale of 1:24, 000, or one inch map distance equals 2,000 feet on the ground. A 7. 5-minute quadrangle would comprise the unit map area. A resolution which urged the preparation of a new geological map of the entire State was passed by the Kentucky Society of Professional Engineers in February 1959, and was presented to the Governor of Kentucky, the Legislative Research Commission, Kentucky Department of Economic Development (now Department of Commerce), Kentucky Chamber of Commerce, and Kentucky Geological Survey with a request for support and action. The request was subsequently endorsed and actively supported by numerous civic and professional societies as well as representatives of various facets of Kentucky government, commerce, and industry. Monies to initiate the program were appropriated by the next session of Kentucky legislature; this appropriation was matched by federal funds (Hagan, 1961). Kentucky's state-wide topographic mapping project was completed in 1956, just four years prior to starting the geologic mapping program. The recently completed modern 7. 5-minute, 1:24,000 topographic maps made ideal bases for plotting areal geology. Had they not been available, it is doubtful if a geo- logic mapping program so large and comprehensive could have been undertaken.

Jan 1, 1966

By Rodrigo Peroni, Vitor Campos

Carajás is one of the largest open pit mines in the world. The mine is comprised by a haul road network more than 100 km long, where the need for good roads is paramount and determining of the truck performances. This work integrates, regarding the ultimate pit design, an approach to consider an economic value to an originally unfit material, assuming it has the appropriate characteristics for haul road construction, which sometimes lies over economic iron ore. This measure demonstrated an improvement in the utilization of resources and guarantee the necessary material to the haul road design and Mining Pads maintenance.

Jun 25, 2023

By Thos. B. Douglas

In 1907, the Oklahoma Portland. Cement Company built a small dry process plant at Ada, Oklahoma, then Indian Territory. This plant was later acquired by the Ideal Cement Company of Denver, Colorado, who in 1918 built a new wet process plant along side the old dry plant. The older plant was later shut down .and eventually razed. In 1955, the Ideal Cement Company decided to increase the production at its Ada, Oklahoma operations. After many studies it was decided to build a complete new plant along side the old, near the site of the original 1907 plant. .The new plant was to have a. production of three million barrels annually while the plant then in. operation had an annual production of two and one quarter million barrels

Jan 1, 1961

By E. Taskin

Diasporic bauxite from the Mugla-Milas region was mechanically activated in a planetary mill for different activation times and the structural changes were examined by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and specific surface area analysis (BET ? Burnauer, Emmett and Teller). Non-activated and activated bauxite samples were leached directly in alkaline (Na2O) solution at atmospheric conditions and the activation procedure led to the amorphization and structural disordering of the diasporic bauxite structure, which increased the dissolution efficiency. Effects of milling speed, liquid/bauxite ratio and leaching time on alumina extraction in direct alkaline leaching of diasporic bauxite were also studied. The alumina extraction was ~7% for non-activated bauxite and ~70% for activated (75 minute) bauxite. Key words: Diasporic bauxite, Mechanical activation, Alkaline leaching, Alumina extraction

Jan 1, 2009

By K. E. Harrison

Acid rain legislation as proposed by President Bush [1], if enacted, will immediately refocus current thinking on the economic decision-making as related to coal preparation facilities. Unit operations currently ignored because of their costs, will become mandatory to coal plant designers and operators to ensure maximum energy recovery and sulfur reduction in the entire coal stream. In anticipation of this need, the U.S. Department of Energy, The Ohio Coal Development Office, EPRI and others are sponsoring research in several areas of coal preparation, and coal plant designers are beginning to consider more innovative techniques as they configure their flowsheets for plants of the future. Preparation plants then will have recleaning

Jan 1, 1990

By R. A. Pyper

Laboratory leaching experiments were conducted to ascertain the effectiveness of acidic solutions of thiourea, CS(NH2)2, for dissolving gold from finely disseminated gold ores. The ore tested was from the Chipmunk orebody of the Northumberland mining district in Nye County, Nevada, USA. Extractions of up to 90 percent were attained from the ore. Extraction was shown to be dependent on thiourea concentration, ferric sulfate oxidant concentration, acid concentration, and leaching time. Optimum conditions were an ambient temperature leach near pH 1.0 utilizing 100-200 kg/t thiourea and 50 kg/t ferric sulfate for 8 to 24 hours.

Jan 1, 1981

By J. A. Organiscak

Two types of airflow splitting methods for improving longwall dust control were investigated by NIOSH's Pittsburgh Research Laboratory. These methods included a translucent mesh barrier and a staged spray barrier system to confine the shearer-generated dust to the coal extraction side of the long wall face while maintaining a cleaner split of airflow on the opposing worker walkway side of the longwall face. The translucent mesh barrier was shown to provide notable dust control effectiveness up to 60 m downstream of the shearer in both the laboratory experiments and a long wall field evaluation, provided the mesh barrier remains relatively parallel to the airflow. The staged spray barrier system showed marginal dust control effectiveness in the laboratory and subsequently was not field tested.

Jan 1, 1999

By L. W. Saperstein

Surface mining of coal is undoubtedly one of the more controversial aspects of the mineral industries today. There is a constant tug between the need for readily available and inexpensive energy supplies and the desire to minimize disturbance to the land. Without a doubt, surface mining severely disturbs the land surface. The duration of this disturbance, from a minimum of a few months to a maximum of infinity, however, is strictly dependent upon the mine operator's willingness to reclaim. Surface mining critics claim that it is impossible to ameliorate the detrimental effects of this mining to insignificance. The more vocal critics, indeed, are calling for complete abolition of surface mining for coal. Thus, they do not believe that it is possible to restore surface- mined land to pre-mining conditions. As a consequence of this position, an adversary relationship has developed between the operators and their critics who, simultaneously, believe they are doing their best for the United States. In a forum of mining experts, there is little need to recount the kind and amount of devastation that can result from poorly reclaimed land. This has been done numerous times, including once 1 by the author. Of particular interest to this paper, though, are the environmental hazards associated with contour strip mining. In addition to the problems of area mining: denudation of vegetation; exposure of toxic spoil; increase of erosion runoff; etc.--contour mining has the very real problem of landslide due to the outslope stacking of overburden. Contour mining is understood to be the extraction of coal from a hillside outcrop such that the resultant pit follows, or nearly follows, an elevation contour. The problem with contour mining as usually practiced is that the spoil from the cut, or the first cut if multiple cuts are made, is placed on the outslope. If this slope is steep, the resulting pile is difficult to stabilize, generally erodes swiftly, and may fail disastrously.

Jan 1, 1973

By Tim Langmaid, Steve Skelhorn, Stephanie Robillard, Allen Mitchell

"The Port Mann Main Water Supply Tunnel project provides a critical water main crossing of the Fraser River for the owner, Greater Vancouver Water District (Metro Vancouver). The project consists of two 60-metre-deep slurry panel shafts and a 1-kilometre-long, 3.5-metre excavated diameter tunnel located near Vancouver, British Columbia, Canada. The initial tunnel lining is a precast concrete steel fiber reinforced gasketed segmental lining. The final lining is a 2.1-metre-diameter welded steel pipe. This paper describes the challenges encountered during tunnel construction and the solutions implemented. Key challenges include earth pressure balance tunnelling at up to 6 bar pressure—the highest to date in Canada—a water-crossing without surface access for the majority of the tunnel drive, ground freezing from a river platform for a critical TBM intervention, and boring through cobbles and boulders in dense glacial till. INTRODUCTION Metro Vancouver supplies drinking water to 18 municipalities, one electoral district and one treaty first nation, serving a population of more than 2.4 million residents. Water is collected in three mountainous watersheds to the north of the Greater Vancouver area, in southwestern British Columbia, Canada. To supply the growing demands of Metro Vancouver’s customers, treated water must be conveyed across two significant water bodies: the Burrard Inlet and the Fraser River. The existing Port Mann water main is one of several key links between the watersheds north of Vancouver and the municipalities south of the Fraser River. The Port Mann Main Water Supply Tunnel (PMMWST) is the first of a series of upgrades, to increase capacity, enhance scour protection, and improve seismic resilience. The new tunnel is 3.5 metres (11.5 ft) in diameter and 1 kilometre (0.6 mi) long. When completed, it will contain a new 2.1 metre (7 ft) diameter steel water main that will help ensure the continued, reliable delivery of drinking water to these municipalities, and will more than double the capacity of the existing 1.2 metre diameter main."

Jan 1, 2016

An AFM has been applied to study in situ the adsorption of oleic acid on fluorite in aqueous solutions. The AFM images show that fluorite surface becomes smoother with the adsorption of 7 × 10-5 M oleic acid solution at pH 9. Force measurement shows that fluorite is strongly positively charged in water at pH 6, suggesting a neglectable surface carbonation of fluorite. The adsorption of oleic acid at pH 9 renders fluorite more and more negatively charged. The surface morphology change of fluorite as shown by the AFM images suggests that oleic acid chemisorbs on fluorite at pH 9. Increasing temperature can help increase the adsorption of oleic acid on fluorite. It may also improve the lateral polymerization of unsaturated oleic acid on fluorite as suggested by the smoother mineral surface in oleic acid solutions at an elevated temperature.

Feb 23, 2014

By Robert M. Cox

Surface mining of coal in the South developed into a major industry during the 1960's. The economic significance of the industry is much greater than is readily apparent when one considers only the value of the coal mined. The abun-dant supply of relatively inexpensive steam coal for electric power generation that has been derived from the surface mines has provided the foundation for the industrial expansion that has occurred throughout the South. The region, in gen-eral, has enjoyed the benefits of plentiful low cost electric power. However, re-cent political decisions, at all levels of government, threaten to destroy or severely curtail the surface mining of coal and eliminate the economic advantages once enjoyed by the region. These political decisions are rapidly changing the basic rules of operation and fundamental economics of surface coal mining. Recent changes, resulting from the enactment of environmental and health and safety laws and various bureaucratic rules and regulations, have had a three-fold effect: 1) Greatly increased operating cost, 2) increased lead times for mine development, 3) limited potential reserve base for future mining. Also current legislative proposals are casting a shadow of uncertainty over the future of all coal mining operations that has created serious delays and in-creased cost for the expansion of the coal industry necessary to meet our project independence goals. Technology Surface mining is the safest and most economical way to produce raw materials from the earth's crust. It also affords a more healthier working environment for the individual miner. Surface coal mining now accounts for more than 60 percent of the annual coal production in the South. Surface mining of coal requires the removal of the overburden to expose the

Jan 1, 1977

By Rudolph H. Jacobson

The leaching of heaps or sub-marginal waste ore dumps as it is practiced throughout the Southwest as well as other parts of the world, is the major method of secondary recovery of copper. In 1970, twenty percent of all domestic copper was produced by dump leaching operations (l). In recent years, this method has been successfully extended on a limited scale, for the recovery of uranium from low-grade ores (2). It is inevitable that this technique will be increasingly employed in metal production to satisfy the insatiable demand of our mineral based society. Although dump and heap leaching has been used effectively for some time (3) , its application has been more of an art than a science. Therefore, it is essential that we learn about the important factors and parameters affecting this versatile process so that we may make increasing use of this technique in the future. The dump or heap leaching process encompasses the preparation of ore for-subsequent inplace leaching, the flow of solutions and ionic species through porous rock masses, the leaching of minerals with inexpensive and, if possible, regenerable lixiviants under prevailing conditions of the inplace environment, and the recovery of metals from the pregnant liquors. It is evident that this comprehensive scope of dump or heap leaching falls under the realm of interdisciplinary science and engineering requiring the application of the principles of physics, mineral engineering, hydrology, computer modeling, operations research, economics, and allied disciplines. An exhaustive study of the phenomenology of a leach dump or heap requires detailed knowledge of the simultaneous interaction of'

Jan 1, 1972

By R. W. Waytulonis

New exhaust control techniques and devices may be necessary to meet future diesel particulate matter emission standards in underground coal mines. This paper reviews conventional work practices and devices used to control diesel exhaust emissions, and new techniques being tested by the Bureau of Mines. Discussions will center on important work practices and on the function and efficiency of exhaust after-treatment devices. An industry/government cooperative research project to develop and test an exhaust after-treatment system for part 36 equipment is also discussed.

Jan 1, 1990