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By G. E. d’Aquin

Sources of sulfur have varied based on technology and societal needs. It has been mined in its elemental form for centuries. Twentieth century technology brought thermal mining (Frasch, 1894) to the forefront of sulfur extraction. Then, by the 1980s, petroleum processing generated almost 40 percent of the 50 Mt (55million st) of sulfur in all forms (SAF) produced in the world. Metals processing (the reclamation of effluent gas by various means as “sulfur in other forms,” or SOF) followed at 30 percent of all sulfur values produced and then Frasch at 22 percent. Petroleum and gas processing now generate most of the elemental sulfur produced in the world. Single Two Frasch mines remain, one each in Iraq and Poland. Conventional mining of small to insignificant volumes also survives in Russia, Latin America and Indonesia. The volume of “recovered” sulfur (the name commonly given by the industry to hydrocarbon-derived material) generated will increase faster than energy consumption as oil and gas with greater amounts of sulfur are used and environmental restrictions on the sulfur content of the fuel consumed become more stringent.

Jan 1, 2005

One of the challenges in the development of mineral processing simulators is the modelling of liberation characteristics of particles produced by comminution circuits. Understanding the mineral characteristics of these particles is one of the keys to predicting their behaviour in separation circuits. While more fundamental research seeks to model the non-random breakage of ores this work examines whether we can move forward now by using observed characteristics of ores to model the composition of particles generated in comminution processes. The current work examines a range of ores and identifies which of these exhibit the pattern of similarity of composition for particles in a given size class that has been produced as the result of a variety of breakage conditions. The impact of mineralogy and texture on the evolution of liberation characteristics for both valuable and gangue minerals is discussed.

Jan 1, 2009

By Frank C. Stevens

The availability, cost and use of fuel and electricity for the cement industry is difficult to predict with a great degree of accuracy because the historical pattern of factors affecting energy was disrupted during the years 1972, 1973 and 1974. Forecasting is both an art and science and is based on .the premise that the best indicator of the future is the past. Statistical data is used to guide economists and businessmen in their predictions of the future. Even though the energy picture is changing, it is believed that electricity and fuel will be available for the cement industry in the foreseeable future, and this energy will be more costly in relation to the other items that are part of the manufacturing costs for portland cement.

Jan 1, 1977

The paper presents results of the mineralogical examination on samples from a bacterial leaching test which simulated in situ leaching for 482 days. Rock fragments (15 to 20 cm) were obtained from the top, the middle and the bottom of a bioleach column. Examination of the samples was carried by electron microscopy and image analysis. The surfaces of the rock fragments were studied to characterize the precipitation products, and cross-section cuts were studied to assess the advance of the bacteria leaching front and the dissolution of the different sulphide minerals.

Jan 1, 1991

By Zoltan F. Oszter

The frictional resistance to motion of a belt conveyor has always been a subject of intensive studies and research by engineers throughout the years. Numerous informations have been developed by analysing series of field tests on belt conveyors of different characteristics and carrying different materials at various capacities. Within certain limits of weight per unit length and tension, the theoretical considerations and the analysis of the field tests, both in the US and abroad, resulted in the development of similar formulas. In general these formulas are safe to use up to the following limits:

Jan 1, 1977

By J. Iannicelli

An entirely new level of magnetic filtration technology was put into full commercial production by the kaolin industry of Georgia, U.S.A. during 1973-1974. At present, four kaolin producers in Georgia are operating large magnetic filters each capable of processing over 1000 gallons of kaolin slurry per minute or over 65 tons of kaolin per hour on a dry basis. A fifth large filter will go on stream in August, 1975. Four of these units are 84" machines manufactured by the Pacific Electric Motor Company of Oakland, California. When operated at the maximum 1000 g, p. m. rate, these five large magnetic filters have a combined capacity approximating the entire waterwashed coating and filler kaolin produced in the U.S.

Jan 1, 1976

By Dan Martz, Stuart Lipofsky, Dean Workman

"The Indianapolis Deep Rock Tunnel Connector (DRTC)—first in a vast network of storm water storage tunnels below Indiana, USA—was a wildly successful endeavor. Crews for the Shea/Kiewit JV drove a 6.2 m Robbins Main Beam TBM to world record rates. The machine achieved 124.9 m/day, 515.1 m/week, and 1,754 m/month in limestone and dolomite rock. The advance rates can be attributed to many factors including ground conditions and knowledgeable crew, but continuous conveyors are also of key importance. The novel conveyor system, manufactured by The Robbins Company, enabled continuous tunneling in a difficult layout that included two 90-degree curves and two S-curves. Spanning 11,777 m in its longest iteration, the system included nine booster drives plus a main drive. A vertical belt moved muck up the 76 m deep shaft to a radial stacker for temporary storage. The system, one of the most complex in North America and the first to operate in 90-degree curves, made swift tunneling possible. This paper will examine the world-class tunneling done at the Indianapolis DRTC and the role of continuous conveyance in reaching high advance rates. The logistics of the system will also be examined as it could apply to future tunneling projects with similarly complex layouts. INTRODUCTION The Indianapolis Deep Rock Tunnel Connector (DRTC) is the first phase of a nearly 28-mile long network of deep rock tunnels being built 76 m beneath the City of Indianapolis, Indiana by Citizens Energy Group. The Deep Rock Tunnel Connector (DRTC) Project is a 12.2 km, 5.5 m diameter tunnel constructed by S-K JV, a joint venture between J.F. Shea Construction and Kiewit Infrastructure Co. The tunnel is a $179 million project and is the first segment and southernmost portion of a deep, large diameter conveyance and storage tunnel system to provide overflow relief during wet weather events. The project is estimated to be completed in 2017 and will initially deliver 204,000 cubic meters of the planned 1 million cubic meters of CSO storage for treatment, as well as provide future connections to other tunnels in the overall system (see Figure 1)."

Jan 1, 2016

By P. Soros

Rich iron ore deposits were discovered during the 1960's in the mountain range of Serra dos Carajas, State of Para, Brazil, near the headwaters of the Tocantins River some 400 miles southwest from the state capital of Belem. (See Fig. 1 and 2). The key to the successful exploitation of this deposit was the development of an efficient an economical transportation system. The rugged terrain, and the dense tropical vegetation of the Amazonian jungle and the irregular coastline with its high tidal range presented severe obstacles to the planning and building of such system. Starting in 1972 extensive surveys and studies were carried out by Soros Associates on behalf of CVRD to determine the optimum way of transporting the ore from the mine site to the markets, most of which are located overseas. Overland transportation to the coast, loading into seagoing vessels and the ocean voyage to the ports of destination was treated as an integrated system in these studies.

Jan 1, 1986

By Son Hoang Nguyen, Thanh‑Hai Pham, Duoc Van Tran, Dung Thi Kim Nhu

Apatite ore plays a critical and irreplaceable role in fertilizer production and is being upgraded in quality in northern Vietnam. The old tailing of the Bac Nhac Son beneficiation plant (Vietnam) has a significant apatite amount in the form of coarse unliberated particles. These millions of tons of tailing ore have 6–8% of P2O5 content, which can be retreated to provide fertilizer factories. This work presents the results obtained in recovering apatite from this tailing in the laboratory. By the combination of the processes of classification, preliminary flotation, re-grinding and cleaning in the flotation column, an apatite concentrate of 30.68% P2O5 can be obtained with the total recovery of 37.76% from the initial tailing of 7.56% P2O5. The study results not only provide an appropriate technical solution for recovering the apatite ore from tailing ore but also have outstanding meaningness in the recovery of mineral resources under the context of a circular economy.

May 24, 2023

By Wi11iam M. Leaders

Uranium Recovery Corporation was incorporated in the State of Florida in 1968 for the sole purpose of developing a method to economically recover uranium from Florida phosphoric acid. The preliminary laboratory work culminated in the demonstration of the process to United Nuclear Corporation in the spring of 1971. This was quickly followed by a pilot plant program to identify any unusual problems such as those arising from the day-to-day variation which occurs in a fertilizer phosphoric acid plant production system. After two years of pilot plant operation, United Nuclear Corporation purchased controlling interest in Uranium Recovery Corporation and committed several million dollars to the design and construction of the first commercial plant for this purpose in the State of Florida, or anywhere else in the United States, for that matter. After many start-up problems were resolved at the production plant located at the W. R. Grace fertilizer complex near Bartow, sustained production began March, 1971, and has continued to date. We still have some problems to solve but are currently producing sufficient uranium to make shipments to the UF6 converters for preparation of Florida uranium for use in nuclear power plant fuel materials.

Jan 1, 1978

By Charles R. Jenkins

Three sedimentation ponds had their performance evaluated before and after installation of modifications. Each pond had a floating baffle installed, two had siphon outlets and one had a floating outlet device. Baffles inhibited short circuiting, and the outlet devices retarded flow following a rainfall event, and drained the pond creating a large storage volume to maximize detention time. Total suspended solids and settleable solids tests were run on samples of influent and effluent to evaluate pond performance. Particle size analyses were run on samples containing measurable amounts of solids. Performance improved in each pond, with baffles providing the major improvement. Through the entire surface mining process un- protected soil is exposed to direct rainfall and subject to accelerated erosion. Without controls, receiving streams would be "choked" by the additional sediment load. Several states, including West Virginia, require that sediment control ponds be constructed to trap the sediment before the water enters receiving streams. Even well designed ponds have exhibited difficulty in meeting effluent limitations. In a study supported by EPA, about half the ponds did not meet effluent limitations (1). There is a critical need to reduce sediment losses using presediment pond controls or by improving sediment pond performance. The objectives of this study were to evaluate modifications designed to improve sediment pond performance by; 1) monitoring three ponds prior to modification, 2) install floating baffles and 3) modify the principle spillway and determine the change in pond performance.

Jan 1, 1985

By D. L. Shenck

The Navajo Mine is exclusively a multiple seam surface coal mine located in the northwest corner of New Mexico, and entirely on the Navajo Indian Reservation (Figure 1). It is owned and operated by the Broken Hill Propriety Co., Ltd. of Melbourne, Australia. The mine began production in January 1963 with a long term fuel supply agreement with the Four Corners Power Plant. The 2175 MW nominal generating capacity of the Four Corners Power Plant consumes 8-8.5 mm tons of coal annually. With estimated reserves totaling 1.1 billion tons of strippable coal, only one third is presently committed to the generating station. As development has continued over the years, mining operations have advanced into more complex geologic areas to satisfy the utilities demand for coal.

Jan 1, 1990

By R. R. Hall

Tests were conducted to assess the potential of column flotation for beneficiation of a talc ore from Montana. This ere contained approximately 80% talc, with the gangue comprised mainly of chlorite, silica, and dolomite. A tributylamine, MIBC, and sodium silicate reagent suite proved effective for talc flotation. Rougher-cleaner column flotation in a continuous open-circuit produced a final talc concentrate which contained 0.90% Al2O3. 0.17% CaO, and 1.28% Fe2O3. These analyses represented impurity rejections of 77, 85, and 65%, respectively. Weight recovery for this open-circuit was 52%; however, weight recovery was estimated to be 75% with cleaner tailings recycle. Results from this investigation show that column flotation is a viable means for beneficiating talc.

Jan 1, 1990

By James B. Fletcher

The Miami mine is located near the town of Miami, Gila County, Arizona. The Miami mine started mining in 1910 and finished in July, 1959. The orebody was divided and mined as follows: Tons High Grade 24,400,000 - Top slicing, sub-level caving, etc. Low Grade 105,100,000 - Block caving Mixed ore 9,800,000 - " Low Grade #2 13,100,000 - " Total Mining 152,400,000 GEOLOGY Ore minerals are largely in pre-Cambrian Pinal schist intruded by tertiary Schultz granite porphyry and covered to some extent by Quarternary Gila conglomerate. The structures are highly faulted and shattered. The Miami fault on the east cuts off the ore and the Pinto fault on the southwest caused re-oxidation of enriched sulphides producing mixed ore. MINERALOGY The chief mineral is chalcocite, with chalcopyrite, bornite, covellite, malachite, azurite, chrysocola, cuprite, native copper, and molybdenite as minor minerals. The ore minerals occur in seams, veinlets and disseminated particles. In block caving there is always some dilution, and drawing of ore stops when the grade drops past an economical point. This results in a small amount of copper left in the stopes below the capping. There is some copper in the capping, probably below 0.03% or less than 0.6 lbs. per ton. Over the low grade #2 orebody and portions of the high grade there was an oxide capping which was not mined. The crushed pilars are another source of copper. The leaching at Miami is an attempt to recover this last remaining copper of a worked-out mine. The enrichment at the Miami mine had gone more nearly to completion than most ore bodies in the southwest. There is practically no pyrite in the capping and very little in the ore.

Jan 1, 1971

By Edward J. Harvey

Joplin, one of the most famous zinc mining camps of a bygone era, is today experiencing a healthy growth in manufacturing enterprises. Manufacturing requires water, and knowledge of its availability and quality often is the main factor in location of industry. For this reason in January 1964, on the suggestion of the former State Geologist, Dr. Thomas R. Beveridge, a study of the water resources of the Joplin District was undertaken as a cooperative effort of the Missouri Geological Survey and Water Resources now under the direction of Dr. William C. Hayes and the U. S. Geological Survey. The project area is in southwestern Missouri on the Springfield Plateau and is bordered on the west and north by the Osage Plains of Kansas and Western Missouri, (fig. l). Upland altitudes rise from 900 feet above sea level in the west to 1400 feet in the east. The countryside is rolling to moderately hilly and much is excellent farmland.

Jan 1, 1965

By A. K. Bakshi

Mineral suspensions show Newtonian flow properties at lower solid concentration, but change into non-Newtonian regime as the solids content is increased. For Newtonian fluids viscosity is independent of shear rate, but for non-Newtonian fluids it varies with rate of shear. Therefore, measurement of viscosity at a shear rate, different from the process will be futile unless the slurry is Newtonian. This is especially true for hydrocyclone operation, where the rate of shear is different at different points within the hydrocyclone. In this case, it is very important to determine the flow type of the suspension before attempting to establish any correlation between viscosity and process efficiency. A new technique to distinguish such changes in flow type has been developed. This involved a co-axial cylinder type viscometer which measured apparent viscosity at a low shear rate, and a vibrating sphere type viscometer which measured the apparent viscosity at a high shear rate. Special precautions were taken to allow measurements of viscosity of rapidly settling mineral suspensions. Because the vibrating sphere viscometer operated at a much higher shear rate than the rotating viscometer, the two instruments together could determine the shear-rate dependency of the viscosity. Ground silica of 80% passing 65~m size in water was used to prepare slurries at concentrations ranging from 1O-70wt% solids. Viscosity of each slurry sample was measured simultaneously by both the viscometers and the results were compared with each other. With this technique, it was found that all the silica slurry samples were in the Newtonian flow regime.

Jan 1, 1995

By V. B. Achanti

Laboratory studies were carried out at West Virginia University to investigate the rock fragmentation mechanism by continuous miners using an automated rotary cutting simulator. The primary factors influencing the: fragmentation process were found to be: bit spacing, bit geometry, depth of cut, and cutting drum rotational speed. This paper presents the influence of these parameters in achieving optimum energy consumption and minimizing dust generation during rock fragmentation process. Three bits were used simultaneously on Indiana limestone while the bit tip angle was varied from 60° to 90°. Bit spacing was varied from 2.54 cm (1 in.) to 5.08 cm (2 in.) while the cutting process was assessed for varying cutting depths. Respirable dust generated during the course of the experiments was analyzed utilizing cascade impactors. Assessment of these parameters has led to a better understanding of the cutting mechanism by continuous miners in terms of energy consumption and dust generation.

Jan 1, 1997

By T. Matthews

"One critical factor in mineral reserves reporting, as well as mine-reserves reconciliation, is the impact of dilution and ore loss in the mining process. This paper considers the implications of various factors on dilution and ore loss projections, by orebody geometry, mining method, and ore control systems. We also discuss the implications of resource estimation methodology on dilution for reserves. DEFINITIONS Dilution and ore loss are two critical concepts in mining, which address the differences encountered between modeled grade and tonnages and actual production. Dilution is volume increase and grade reduction caused by multiple factors, chief among which are mining of waste material along ore-waste contacts, mining of internal waste as ore, and misclassification of waste as ore in the ore control process. There are also geostatistical and estimation aspects sometimes lumped with dilution, including the volume-variance effect (the tendency for small volumes of material to include a less regular distribution of grade than large volumes of material). Ore loss is described as reductions of ore volumes in the mining process due to misclassification of ore as waste in the ore control process, exclusion of discontinuous mineralization from mining due to geometry or continuity, and mechanical losses in the mining process. Dilution is typically taken as an increase in tonnes of ore with no change in contained metal (and thus results in a reduction in grade.) (Some workers consider the likely grade of the diluting material as well, particularly in deposits with gradational grade boundaries—this will be addressed later in the text.) Ore loss is typically taken as a reduction in tonnes at average grade of the ore, and thus results in a reduction in both tonnes and contained metal. If model (resource) tonnes are Mt, grade is Mg, and contained metal is Mm, the resource with ore loss (L) and dilution (D) included (Rt, Rg, and Rm) will be:"

Jan 1, 2015

By M. A. Gibson

Ilmenite-rich lunar deposits can be converted to liquid oxygen to support lunar base operations and space transportation propulsion needs by a Carbotek-developed process. Iron oxide in ilmenite is reduced at elevated temperatures by hydrogen in a fluidized-bed reactor to water vapor which is electrolyzed to product oxygen and recycle hydrogen. Reaction rate, thermodynamic equilibrium, and lunar-gravity fluidization behavior are key factors which have been considered. Fluid-solids behavior has been modeled from data taken at lunar gravity conditions aboard NASA KC-135 flights. Large-scale pilot plant operations are planned to complete the development.

Jan 1, 1991

By C. Patrick

Project scheduling is a deterministic technique utilizing single estimates of activity durations. In reality, activity durations are stochastic and can be better represented by probability distributions. This paper describes the development and utilization of a project scheduling simulation which combines analytical scheduling with stochastic activity durations. The purpose is to provide a method to analyze the sequencing of mining production processes and predict the effect of any planned changes. The simulation is demonstrated through realistic examples, such as longwall face-to-face transfer sequencing and the effect of varying advance rates on longwall development sections. Statistical data, to make more informed production decisions, are generated in the form of project activity/path criticality and project duration distributions.

Jan 1, 1995