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By Martin H. Stanczyk

In recent, years the demand and consumption of finely ground industrial minerals has substantially increased for such uses as fillers and chemically reactive components. The size, specifications for these types of industrial mineral materials vary to a great extent and depend on the particular end purpose' and on the physical properties of the mineral itself. Size reduction of industrial minerals usually is obtained by conventional crushing and grinding methods. However, some specialized milling techniques have been developed for producing these minerals in extremely fine particle size ranges. During recent years the Bureau of Mines has been investigating an attrition grinding method to produce ultrafine subsieve-size mineral particles. The Bureau developed process, which has been patented,2 comprises the intense agitation of a slurry composed of the material to be ground, a relatively fine granular grinding medium, and a suspending fluid. The process has been shown to be effective for the comminution of kaolin in the particle size range of 2 microns and finer on a batch3 and continuous basis.4,5 This report presents the results of batch tests made to determine the effectiveness of the attrition grinding process for comminuting commercial products of (1) mica, a tough lamellar material, (2) fluorite, a brittle intermediately hard material, and (3) barite, a relatively soft, massive material.

Jan 1, 1967

By Jacob Grasmick, Bill Newns

Despite ongoing digitization and “hardware” technological advances, geotechnical uncertainty remains the most significant risk in underground and tunnel construction. And, whilst they are commonly held up as an example of the sophistication of the industry, the practice of drafting and using geotechnical baseline reports is subject to a wide range of influences, not all of which support good risk management. Uncertainties in predicting ground behavior, the gap between the pre-construction assumptions, and the systemic response to construction remains a significant technical and communication challenge. Accordingly, this paper presents a framework to quantify geotechnical uncertainty using geostatistics and translate these into practical tools for ground risk management throughout planning, procurement and construction. Adopting even some of the principles of this framework should provide improvements to contract risk management and should assist to minimize the potential for commercial losses.

Dec 1, 2022

By A. W. Khair

Surface subsidence is a phenomenon mainly associated with longwall mining, although it can also occur if the coal pillar left to protect the surface deteriorates with time and results in the collapse of the room and pillar system. A method has been developed that utilizes physical mine models and laser holographic interferometry. This method is capable of measuring displacements as small as 5 micro- inches by means of generating displacement contours on a surface, even that of granular materials. Analysis of subsidence in room and pillar mining using models of various extraction ratios ad overburden depths along with two different types of overburden model material (sand and gelatin) has been made. The sand represented the extreme brittle conditions of geologic material while the gelatin represented visco-elastic behavior of geologic material. This paper deals with the analysis of data which has been gathered up to date, and mainly associated with the use of sand as an overburden model material. The analysis included the effect of variation of geometric parameters on surface subsidence. Among these parameters are: variation in seam depth and thickness, surface and seam inclination, and extraction ratio.

Jan 1, 1984

By T. Lupek, S. Plaum

"The execution of classical building services in underground mining operations is more truth than myth. From small concrete foundations for conveyor belts to the construction of huge workshops for large machinery maintenance, nearly every operation requires building services. By creating such fixed facilities, these services ensure the efficiency of the production. A distinction must be made between fixed facilities which directly enable the production and auxiliary facilities which only indirectly support the production. The construction costs of such auxiliary facilities are often roughly estimated because they do not immediately contribute to mineral extraction. The research project ‘Development of a systematic cost-calculation method for building services in underground mines’ seeks to address the question: ‘Can the construction costs concerning fixed auxiliary facilities be neglected e.g. within a prefeasibility study?’ The presentation will show the monetary relevance and significance of these auxiliary facilities and introduce a guideline for cost estimators. PROBLEM DEFINITION The overriding interest of an underground mining operator is to exploit the commodity with the maximal quality by minimum cost and time expenditure. If a new operation shall be installed, it has to promise profitability. Therefore, predictive economic feasibility studies are performed in advance of installation. Herein, all cost expenditure for installation and operation of the future underground mine is determined and compared to the expected income by selling the raw material. The described interest of the mining operator is the starting point of the research project ‘Development of a systematic cost-calculation method for building services in underground mines’. While economic feasibility studies for future operations are focused on the profitable exploitation of raw materials and the efficiency of the accompanying necessary production processes, auxiliary actions are only considered rudimentary. Necessary production processes, as well as auxiliary actions regularly require classical building services, which are normally performed in construction business on the surface in the same manner. By performing building services like masonry or concrete works in underground mines, fixed facilities shall be set up in order to enable or support the raw material production. Production enabling fixed facilities are varying from small concrete foundations for conveyor belts or other infrastructural elements to upstream processing plants situated in the mine workings. While such fixed facilities are essential parts of the production process chain, supporting facilities underground shall increase the efficiency of the mining operation. Workshops, control rooms and social installations are only a few examples for supporting facilities. Those could be situated on the surface as well, but the efficiency increases significantly by installing them underground. Especially supporting facilities are evading from the main interest of the mine operator, since they are only indirectly connected to the production process. The building costs are oftentimes only roughly assumed."

Jan 1, 2017

By T. A. Farr, I. A. Gibbs, F. Guevara, S. R. Simms, G. Nojima

This paper describes an installation of a medium-voltage adjustable frequency motor drive (AFD) on a high starting torque regrinding mill. This type of application is typically found in the mineral industry dealing with hard ore. The AFD electrical architecture is introduced from line to load. The type of closed loop encoder feedback motor control algorithm is briefly described. The results of the AFD motor identification auto-tuning are compared against the manufacturer’s supplied data. The motor drive performance results are shown for pre-ramp DC fluxing, high starting torque with overload current, excessive load torque stall condition, and blocked rotor. The instrumentation and arrangement for the two watt-meter method to capture low frequency data are presented. The data shown is from the input power quality meter, the AFD computer tool, the output motor protection relay, an oscilloscope, and load shaft connected strain gauge (rotating telemetry for torque assessment). These types of high starting torque constant torque loads are found in mining and process industry applications employing AC adjustable frequency drives. Using field results should help demystify the use of voltage matching output transformers in AFD applications including constant torque loads

Mar 2, 2022

By G. Wang, L. R. Moore, Y. Xiong, A. Gorken

"Feldspar may represent 60% of the earth’s crust, but the mineral does not exist in a pure state. It is generally associated with quartz, iron containing minerals such as mica, and titanium containing minerals such as rutile. Feldspar itself can even exist in different lattices from those containing sodium to various divalent ions. As such, its beneficiation has become a process that is quite complicated, when compared to the beneficiation of other minerals. It is this complexity that has made feldspar beneficiation dependent on tailor made reagents to successfully yield the industry specified feldspar products. This paper reviews the mineralogical variations found from two feldspar mines and the development of collectors to specifically target a Fe+Ti concentration of < 0.05%, while maintaining a feldspar recovery greater than 90%.INTRODUCTION Feldspar is a class of aluminum silicates that represents the most abundant mineral on earth (Vidyadhar, 2002). This class of mineral can further be defined by the types or concentrations of cations present in the crystal lattice, MAlSi3O8 (M = K, orthoclase and microcline; M = Na, Albite; M = Ca, Anorthite) (Heyes, 2012). Feldspar is most commonly mined and processed for either the alumina used in glass making or for the alkalis used in ceramics. The alumina is known to improve product hardness, durability, and resistance to chemical corrosion. The alkalis act as flux, which means they not only lower the melting temperature of the mineral mixture, but also assist in connecting the other components present in ceramics. It was stated in 2009 that the world production of feldspar was in excess of 18.3 million tons produced, with the majority coming from China, Italy, and Turkey. Raw feldspar is typically found with quartz, iron containing minerals such as mica, titanium containing minerals such as rutile, and other feldspar minerals (Celik, 2001). Quartz is stated as having a negative effect on the melting point of the feldspar, whilst the iron and titanium based mineral contaminants are known to have negative effects on color and quality of the product produced; these mineral contaminants must therefore be separated prior to application (Barns, 1997 & Celik, 2001). Mineral flotation and magnetic separation are the most common means of feldspar beneficiation. However, conditions vary greatly from mineral contaminant to mineral contaminant (Table 1). Some literature suggests feldspar can be floated with an amine, but this generally yields lower than acceptable recoveries and often still requires the magnetic separation of iron based minerals to achieve the desired grade (Amarante, 1997 & Heyes, 2012). Feldspar flotation can be further improved with the addition of hydrofluoric acid (HF) as a silica depressant and feldspar surface modifier, but this still requires the removal of some of the other minerals first. Rutile can be floated with an anionic fatty acid collector at a pH range of 7-8 or with a petroleum sulfonate at a pH < 4 (Celik, 2001), while mica can be floated with a petroleum sulfonate or an amine collector at a pH of 3.5."

Jan 1, 2016

By Z. Xu, Z. Li

Colloidal interactions play a critical role in mineral processing, including grinding, physical separation (particularly flotation), dewatering, and tailings management. Despite great energy input in comminution to liberate valuables from gangues, heterocoagulation between valuables and gangues would prevent the separation of valuables from gangues. On the other hand, selective coagulation/flocculation to increase the size of desired fine particles could enhance physical separation and dewatering, while dispersion is needed for fine grinding. To control the state of colloidal dispersions by creating favorable conditions, it is of paramount importance to study colloidal interactions in a relevant system and understand underlying mechanisms. This review summarizes recent advances in developing the-state-of-the-art techniques and novel methods of measuring colloidal forces, including atomic force microscope, surface force apparatus, zeta potential distribution measurement, quartz crystal microbalance with dissipation, and our recently developed integrated dynamic force apparatus. The basic principle of each technique was introduced first, followed by a summary of critical information derived for the relevant mineral processing systems. Finally, the pros and cons of each technique were discussed to emphasize the use of complementary techniques that assist in solving fundamental problems in mineral processing.

By J. C. Bradbury

The Illinois State Geological Survey&apos;s program in industrial minerals is twofold-the gathering of information on mineral raw materials and the generation of data on the use of these materials. The first function is carried out by the Industrial Minerals Section and the Clay Resources and Clay Mineral Technology Section of the Geological Group, and the second is the responsibility of the Chemical Engineering Section of the Chemical Group. Gathering in formation on raw materials includes both mapping of resources and fundamental geological research. Recent and current research projects include studies relating lithologies of limestones to their physical properties, investigation of sulfur dioxide reactivity of various types of limestone, lithostratigraphic studies of limestones of Mississippian age, investigations of heavy minerals in Cretaceous, Tertiary, and Pleistocene sands, studies of the environments of clay deposition, electron microscope studies of clays and limestones, and investigation of long-term expansion in ceramic products. A relatively recent development that relates more to dissemination of information than to research is environmental geology. This affects the Survey&apos;s industrial minerals program chiefly by stimulating the study of rock and mineral resources in metropolitan areas and reporting the results for the land- use planner as well as the engineer or mineral producer. The Survey&apos;s program of research on the use of industrial minerals was expanded and diversified in 1966. Incorporating a minerals beneficiation lab, the program is designed to develop new uses for existing mineral resources and to assist producers in implementing these ideas: Projects of the minerals engineering program have included the separation of a feldspar concentrate from certain glacial outwash and river sands, recovery of kaolinite from the waste from silica sand operations, development of the use of an Illinois clay as a binder for pellets, and investigations into the use of fly ash and fluorspar mine tailings.

Jan 1, 1970

By Anna Kate Miller, James J. Brady, Hamza Jaffal, Ritika Sangroya, Chadi El Mohtar, Wing Shun Kwan

"The design of an appropriate pre-grouting program can be the difference between a successful tunnel construction and an expensive on-the-go repair. However, current grout design relies heavily on rulesof- thumb and outdated charts. The geotechnical investigation is rarely targeted towards grouting design and the final grouting decisions are made based on fines content or soil classification. The current paper presents an experimental study performed to determine the optimal grout for a tunnel in soft ground below the ground water table (GWT). The testing program consisted of sieve analysis and undrained static triaxial tests on reconstituted sonic samples. Rheological tests were used to compare the different grout mixes and identify best candidates before performing one-dimensional permeation tests. Pressure and volume measurements during the permeation tests, along with the unconfined compression strength results on the permeated soils, helped evaluate the filtration potential for the different grouts and select the optimal grout.INTRODUCTIONConstruction of the Millwoods Double Barrel Replacement Project commenced in 2009 and was expected to be completed by 2015. To facilitate ongoing city development in south Edmonton, the City implemented construction of a major sanitary trunk network along 91st Street and 30th Avenue. The project involved the design and construction of approximately 1.2 miles (2 km) of 7.8-ft (2,400 mm) sanitary tunnel and 2.1 miles (3.4 km) of 11.5-ft. (3,500 mm) and 9.5-ft. (2,900 mm) storm tunnel. Part of the project also involved the conversion of the existing double barrel storm and sanitary trunk to full sanitary service, and reconnecting the local storm sewers from the double barrel pipe to the new storm tunnel. The tunnels range in depth from 26-ft. (8 m) to 115-ft. (35 m) and are being installed using a one pass system with precast concrete segmental liners."

Jan 1, 2016

By D. E. Munson, T. M. Torres, D. A. Blankenship

The Thermal/Structural Interactions (TSI) In Situ Tests are a series of large scale, well instrumented tests that have been constructed at the Waste Isolation Pilot Plant (WIPP) in southeastern New Mexico. As a precursor to the TSI tests, a ventilation drift (Room D) was mined, drilled and instrumented. This room provided the contractor an excellent area to practice controlled construction methods and was a proving ground for construction monitoring and documentation methods. All gages in this first room have been monitored since their initial installation, which has provided a small, but representative, data base. These data also were the first to be available from any TSI area for analysis. This paper discusses the construction activities in Room D and the data generated from the construction and drilling. Deformation of the room is compared briefly to numerical calculations that used a rather simple creep model as a reference. The constitutive model for salt, it appears, must be improved before it can predict the underground deformations.

Jan 1, 1986

By Roger C. Wilmoth

The most common method of treating mine drainage to prevent water pollution consists of neutralization and aeration. This process removes the acidity, iron, aluminum, and some other heavy metals, but does not render a water suitable for domestic or industrial use because of the high dissolved solids, hardness, and sulfate in the treated water. The Environmental Protection Agency (EPA), has been sponsoring and conducting research since 1966 on the use of reverse osmosis (R.O.) for the treatment of mine drainage. This process has been found to be highly effective in the removal of nearly all the dissolved solids. In addition, since R.O. is a concentrating process, potentials for recovery of valuable heavy metals are possible. This paper is a review of the state-of-the-art on the treatment of mine drainage by reverse osmosis.

Jan 1, 1972

By M. Werner

Mining in the Coeur d&apos;Alene Mining District has been going on for over 100 years with a long- term continuation very likely. Mining is presently carried out at depths below the -5000&apos; horizon. As mining continues at ever increasing depths, higher in-situ rock stresses and subsequent rock deformation is encountered making mining costly and hazardous. To provide access for men and materials in such areas, a wooden raise preparation structure is typically built. Although these structures provide adequate support and access, they have proved to be very costly to construct and maintain.

Jan 1, 1986

By Odin Wilhelmy

Agriculture in the United States today is becoming more and more a business, rather than a way of life. In the light of this, it behooves the farm-supply industries that provide the American farmer with his tools of production--feed, fertilizer, machinery, and the like--to give even greater attention than they have in the past to meeting the needs of the farmer-businessmen they are serving. Increasing competition among the companies that make up these industries merely accentuates this need for better service. An opportunity for such improved service, not yet fully realized, exists in the fertilizer industry today. That opportunity lies in the increased transportation of fertilizer ingredients by water. However, before the benefits inherent in this increased water movement of fertilizers can be fully realized, certain obstacles must be met and overcome. It is the purpose of this paper to outline the nature and magnitude of this opportunity, to point out some of the roadblocks and the steps that can be, or are being, taken to remove them, and to indicate some of the rewards that would logically stem from success in these efforts.

Jan 1, 1961

By Richard B. Muter

1. Coal Preparation Terms (General) 1.1 Coal preparation-collectively, physical and mechanical processes applied to coal to make it suitable for a particular use. 1.2 Run of mine (ROM coal)-coal produced by mining operations, before screening, crushing, or preparation. 1.3 Raw coal-coal that has received no preparation other than possibly screening or crushing. 1.4 Raw coal feed-raw coal supplied to a plant or machine, in which it undergoes some form of preparation. 1.5 Coal cleaning-the treatment of coal to lower the mineral matter content (ash). 1.6 Cleaned coal; clean coal-coal produced by a cleaning process (wet or dry). 1.7 Middlings-a product of coal preparation that, by reason of its ash content, is intermediate between coal and discard. It follows therefore that the relative density of middlings is intermediate between those of coal and discard. Middlings may be reprocessed. 1.8 True middlings; bone comparatively high ash particles so nearly homogeneous that their quality cannot readily be improved by crushing and recleaning. 1.9 False middlings; interbanded middlings-middliigs in which the particles consist of bands of coal and shale, and from which the coal may be liberated by crushing 1.10 Refuse-waste material in the raw coal which the cleaning process removes. (See also discard; dirt; stone, No. 1.12). 1.1 1 Reject-the material extracted from the feed during cleaning, for retreatment or discard. 1.12 Discard; dirt; stone--the material extracted from the raw coal and finally discarded. 1.13 Recirculation-the operation in which the whole or part of a product from a process is returned to the feed to the process, e.g., the return of the crushed overflow from a screen to the screen feed for rescreening. 1.14 Foreign coal-coal received at a preparation plant from a colliery other than that to which the plant is attached. 1.15 Imported coal-coal coming from a foreign country, or other state within the country. 1.16 Low-grade coal combustible material that has only limited uses owing to undesirable characteristics (eg., ash content or size). 1.17 Segregation-partial separation of a previously mixed material into its constituents, occurring as a result of differences in either particle size or relative density. 2. Cleaning Characteristics 2.1 Washability-amenability of coal to improvement in quality by cleaning. 2.2 Float-and-sink analysis-the division of a sample into relative density fractions with defined limits, the proportions of the fractions being expressed as percentages of the total sample, commonly with an indication of the ash percentage (and other characteristics, if required) of each fraction.

Jan 1, 1991

By G. A. Gruber

A flotation process has been developed to successfully treat ore from the Santo Domingo phosphate deposit in Baja California Sur. The ore contained less than four percent P205 with quartz, silicates, and carbonates as gangue minerals. Flotation of the low grade feed In sea water required that the conventioinal Crago Process, comprising direct anionic flotation, deolling, and inverse cationic flotation be augmented by an anionic cleaner flotation step, phosphate depression, and a calcite flotation step.

Jan 1, 1986

By G. H. Gronhovd

The U.S. Geological Survey estimate of the total remaining reserves of lignite in this country as of Jan. 1, 1967 was about 448 billion tons. This represents 27 percent of the total coal reserves on a tonnage basis and about 17 percent on a thermal basis. Approximately 98 percent of these reserves are in a vast lignite field located in western North Dakota and eastern Montana. This field also extends north into the Canadian province of Saskatchewan. Despite these large reserves and relative ease of mining by stripping operations, lignite production historically has accounted for less than 1 percent of the national total. This is largely due to the fact that the lignite deposits are located in an area that has no large centers of population and the economical radius of transportation is limited by its relatively high moisture and low heating value. Commercial utilization of North Dakota lignite for power production became firmly established in the mid-1920&apos;s with the development of the first successful lignite-burning equipment. Most of the early lignite-fired boilers were equipped with spreader stokers, but as the size of the plants increased, pulverized-coal firing became the more popular method, and with few exceptions, the plants built during the past 15 years are pc-fired.

Jan 1, 1968

By M. Fig, A. Juganda, M. Zurhorst, J. Brune, C. Strebinger, G. Bogin

"Understanding the airflow patterns in and around the longwall panel can help to identify poorly ventilated areas that may be prone to methane accumulation. Ventilation network modeling provides quick simulation time, and flexibility in adjusting airway parameters and ventilation controls. Such modeling is effective for analyzing linear ventilation networks in underground mines, but cannot compute flows in caved areas of hard rock mines or longwall gobs. The use of Computational Fluid Dynamics (CFD) enables a more detailed investigation of the interaction between the airflows in these caved areas but requires much longer computational times, designing complex meshes and determination of a variety of modeling parameters. Airway friction factors and ventilation controls are simple to implement in a network model but can be difficult to model and adjust in CFD. This paper will focus on using mine ventilation network simulation to identify and analyze key parameters that are affecting airflow distribution in and around the longwall panels, prior to more detailed analysis with CFD modeling, using the example of a longwall coal mine. INTRODUCTION In longwall coal mine ventilation systems common in the U.S., the main purpose of bleeder ventilation is to dilute methane gas and prevent the formation of explosive gas mixtures in the caved, poorly ventilated gob areas and adjacent mine workings. In longwall operation, these critical areas include the development headings inby the longwall face, and the gob. Methane-air explosions in these areas may be ignited by spontaneous combustion, rock-on-rock friction and other sources. Although rare, ignitions due to rock-on-rock friction caused by roof falls caving into the longwall gob are possible and were suspected in the Willow Creek mine explosions in 1998 and 2000 (Elkins et al., 2001; McKinney et al., 2001). Rock-on-rock frictional ignitions are difficult to prevent, as they occur in inaccessible areas. Therefore, rendering the gob area inert is essential to prevent the formation of explosive mixtures. Research by Gilmore et al. (2015) and Brune et al. (2015) has shown that gob inertization can be a difficult or impossible when using bleeder systems, since the flow of gases through the gob depends on the gob permeability and the amount of fresh air leaking from the face and the immediate roof caving conditions cannot be controlled by the mine operator. Having the ability to predict the location where explosive gas zones (EGZs) form inside the gob will be helpful for designing the best ventilation setup to minimize explosion and fire risks."

Jan 1, 2018

By AKIHIRO YOSHIMURA, HIDEKAZU KATO, KOTA TAKATORI, YASUNARI MATSUNO

Chalcopyrite (CuFeS2) is the most refractory copper mineral when treated in conventional sulfate media leaching systems. This study is the first to examine the use of a dimethyl sulfoxide (CH3SOCH3), or DMSO, solution containing copper chloride (CuCl2) in the leaching of chalcopyrite. The DMSO solution containing CuCl2 could selectively dissolve the valuable metals of copper (Cu) and gold (Au) from chalcopyrite while leaving minerals with little economic value, such as pyrite (FeS2), and the penalty element arsenic (As) in the residues. Leaching chalcopyrite using a DMSO solution that contains CuCl2 offers a number of advantages, including eco-friendliness and easy operation.

Fundamental results obtained from research on the properties of the edge surfaces of kaolinite particles (~500 nm) are reported. Of particular significance was the development of the experimental protocol. Well-ordered kaolinite edge surfaces were prepared as an epoxy resin sandwich structure having layered kaolinite particles in the center of the epoxy resin sandwich. Images of the sectioned kaolinite edge surfaces were examined by atomic force microscopy (AFM), and the average thickness of kaolinite particles in this study was determined to be 38.3 nm ± 11.7 nm. Furthermore, the surface charge of the kaolinite edge surfaces was evaluated with a super sharp Si tip. The point of zero charge (PZC) of the kaolinite edge surface was determined to be below pH 4, in contrast to the traditional view that the edge surfaces of kaolinite particles may carry a positive charge at pH 4. This lower PZC of the kaolinite edge surface was attributed to the lack of isomorphous substitution in the silica tetrahedral layer when compared to the PZC for the muscovite edge surface. Our results are consistent with the particle aggregation and flotation behavior of kaolinite, and should provide the basis for improved flotation strategies leading to the efficient recovery and utilization of mineral and energy resources.

Feb 23, 2014

By Paul F. Ziemkiewicz, Aaron Noble, Christopher R. Vass

Many modern industries rely on rare earth elements (REEs) to produce products that are essential to both civil and defense applications. In a prior study (Vass et al., 2019), we showed that REE grades in acid mine drainage (AMD) and associated byproduct precipitates from AMD treatment (AMDp) warrant evaluation as a feedstock for REE production. The current work extends that effort through a broad survey of 141 AMD treatment sites in Northern and Central Appalachia. In this study, 185 raw AMD and 623 AMDp field samples were obtained and analyzed to assess the REE and major metal concentrations. Results show that an average of 282 μg/L and 724 g/t of REEs occur in AMD and AMDp, respectively. Additionally, both basins contained similar distributions of REEs, and these distributions tended to favor heavy and critical REEs when compared with traditional REE ore deposits.