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By Collon C. Kennedy, Frances C. Hartogh, C. Joel Casburn

INTRODUCTION During the nineteenth century, the federal mining law was enacted with the objective of promoting the development of the western United States by providing unrestricted access to vast areas of federal land for mineral exploration. Prior to the advent of comprehensive federal, state and local land use plans, there was little, if any, regulation or restriction of mineral exploration activities. Today, the laissez-faire policies of the past that encouraged mineral exploration have gradually given way to the public's legitimate concerns regarding environmental protection, multiple use and planned land development. As a result, the contemporary prospector confronts a maze of statutes, ordinances and regulations with which he must comply to obtain the requisite approvals and permits before commencing mineral exploration on federal, state or private lands. This presentation will provide a broad overview of the exploration permitting process. The first section of this paper recommends certain general management practices to follow when attempting to obtain exploration permits. The second section presents two hypothetical cases, one involving a drilling program on private property in California and the other involving a drilling program and the removal of a bulk sample for metallurgical tests from federal land in Nevada. The cases are used to discuss jurisdictional issues and application of certain federal, state and county laws and regulations that pertain to mineral exploration. The final section contains a brief analysis of three important recent United States Supreme Court decisions. These decisions address the scope of the federal pre-emption doctrine as it applies to activities conducted on unpatented mining claims and the constitutional limits of permissible state and local land use and zoning regulations. PERMITTING PRACTICES The environmental impacts associated with mineral exploration generally result from the construction of drill sites, roads or trenches. Consequently, after the regulatory authority has considered the issues of permissible land use, the primary emphasis of the permitting process is to address problems related to pre-construction site identification and clearance, and post-construction site reclamation. The approaches taken to address these and other related issues vary with the scope of proposed work, the site, the appli-

Jan 1, 1987

"Foreword by Emily SarverAssistant professor, Mining and Minerals Engineering, Virginia Tech, Blacksburg, VAThe Mineral Processing Division hosted its fifth Student Poster Contest during the 2014 SME Annual Meeting and Exhibit in Salt Lake City, UT – and, by all accounts, it was a huge success! This year, the contest more than doubled in numbers of individual entries and schools represented. A total of 30 students participated, including 23 graduates and 7 undergraduates, representing 13 US and international institutions: Colorado School of Mines, Michigan Tech, Missouri University of Science and Technology, Montana Tech, New Mexico Tech, South Dakota School of Mines, University of Kentucky, University of Utah, Virginia Tech, West Virginia University, Autonomous University of Chihuahua (Mexico), UNAL Medellin (Colombia), University of British Columbia (Canada). In addition to constructing their posters, students submitted abstracts and gave short oral presentations highlighting their research. Based on tallied scores from all three components of the contest, the judging panel selected 1st, 2nd and 3rd place winners at the undergraduate and graduate levels, which were announced during the MPD Luncheon on February 26.In the undergraduate division, University of Utah’s Lucas Pich was awarded the 1st place prize for his poster “Solid-liquid mixing studies in lab-scale flotation tank using electrical resistance tomography.” His extended abstract is included in this issue of Minerals & Metallurgical Processing. Joshua Chidester, also of Utah, won 2nd place for his poster presenting “Evaluation of detectors for radiotracer RTD measurement by MCNP.” And Lucas Rojas-Mendoza, of UNAL Medellin, took 3rd place for his poster on “Preg-robbing in Colombian gold ores.”In the graduate division, 1st place went to Caelen Anderson, of the Colorado School of Mines, who also placed in this contest in 2012 and 2013! The 2nd and 3rd place prizes were awarded to Jacob McDonald and Joseph Halt, respectively, both of Michigan Tech. Extended abstracts describing the work of these up-and-coming researchers are also included in this issue.The 2014 Contest was chaired by Emily Sarver (Virginia Tech) and Lisa Schlink (Freeport-McMoran Copper and Gold, Inc.). Aaron Noble (West Virginia University), David Perkins (Derrick Corporation) and Derek Novotny (Eriez) graciously served on the judging panel this year.Special thanks are extended to all sponsors of the 2014 MPD Student Poster Contest, and to all student participants. Please watch for upcoming details on the 2015 Contest. We look forward to seeing you in Denver!"

Jan 1, 2015

By J. LaForest, R. Riggle

In today’s challenging mining environment, everyone is focused on minimizing cost per ton. With haulage costs approaching up to 45% of the overall mining costs, and loader performance driving production, optimizing payload on the truck is a big opportunity. This paper will focus on technology’s role in loaders achieving the truck target payload. There are constantly new innovations in technology, but not everyone uses them correctly. Technology is intended to help achieve the next level of performance, but still requires the right people and processes to effectively utilize the benefits. In today’s mining business, miners, engineers, trainers, supervisors, and managers have ever increasing roles and responsibilities as never seen before in past decades. Technology can make these roles more efficient, but fully relying on the technology can detract from optimization. Sometimes the old-fashioned method of loading to a consistent pass match will provide a lower cost per ton. Before blindly trusting your technology feedback, know these three areas discussed in this paper: (1) Prerequisites to utilize technology in payload management; (2) Types of payload management technology; (3) How to use the data to manage operator behavior. The objective of this paper is to provide low-cost recommendations to efficiently increase production. INTRODUCTION Whether miners claim to have been around and experienced it all, or they are the data-driven new generation on the mine site, miners are expected to execute the mine plan at the lowest cost possible. So why is it so difficult to execute this task? Shouldn’t supervisors just have to staff the equipment, tell operators to have a safe day and tally up the numbers at the end of the shift? Let the technology system do the rest; what could go wrong? Lots. Having examined numerous mining operations that use the latest loading technologies over the past several years, one common denominator is the opportunity to improve loader operator performance. Mining companies seek help from consultants, training departments, performance reporting systems and an arsenal of resources. Armed with all this information, but the improvements don’t happen, what could have gone wrong? It comes down to people, not managing the resources to drive the right behavior and as a result, the mine’s performance is not where it should be. Understanding how to make “Great Miners” out of these people is critical to this constant struggle to move more with less and get the costs down. Extraction CPT (Cost-Per-Ton) is most sensitive to optimizing loader production which can be generalized into 3 categories of influence: machine specifications, cycle timing, and continuous management using technology. After establishing a basic production machine configuration, utilizing technology to manage cycle times, operator efficiency and payload can be advantageous. Prerequisites to Utilize Payload Management Technology It is important to begin with the primary considerations that enable the use of technology to continuously manage loading productivity. All systems are interdependent in mining, but these are divided into the simplest terms to remember. First, fix your timing and geometry.

Jan 1, 2019

By K. Lagnese, C. Robinson, S. Muddasani

"Mine water generated from underground coal mining operations contains both dissolved and particulate solids. Dissolved solids primarily consist of sodium, calcium, magnesium, potassium, chlorides and sulfates. When discharged to a receiving stream without treatment, these constituents create a potentially toxic environment for aquatic life. A case study is presented to discuss how a centralized treatment plant treats mine water from six locations to meet discharge limitations for chlorides. Located in West Virginia, this facility consistently achieves less than the NPDES permit limitation of 218 mg/L chlorides in the discharge while generating almost zero liquid waste. The dissolved solids concentration in the influent ranges between 5,000 and 10,000 mg/L, with chloride concentrations of 1,000 to 2,000 mg/L and sulfate concentrations of 2,000 to 6,000 mg/L. The mine water is treated using advanced treatment technology to produce clean water for discharge or reuse. The treatment process comprises aeration, softening, filtration, reverse osmosis, RO reject softening, evaporation, crystallization, final effluent remineralization and sludge dewatering. The solid waste generated in the treatment process is landfilled on site. The leachate is sent back to the facility’s thermal treatment process. Because no liquid waste leaves the property, this plant is termed a “Zero Liquid Waste” (ZLW) facility. INTRODUCTION The advanced water treatment system was built to meet a new 218 mg/l regulatory limitation imposed by the West Virginia Department of Environmental Protection for chlorides discharged to surface waters. The system is designed to treat a maximum flow of approximately 5 million gallons per day (795 m3/h) of mine water. The treatment process utilizes reverse osmosis (RO) membrane treatment to achieve the effluent criteria, and evaporation and crystallization technology to manage the RO concentrate from the water treatment process. As a result, the system produces clean water for discharge while generating zero liquid waste. The effluent water can be used for industrial purposes or discharged to a receiving stream. A Water Impact Index (WIIx) study indicated that discharge of this high-quality water into the Monongahela River watershed may improve the water quality for downstream water users. The waste produced in the treatment process, including softening sludge and salt, is disposed of in an on-site landfill."

Jan 1, 2015

Gold cyanide equilibrium adsorption isotherms in the loading range typical of operating carbon-in-pulp/carbon-in-leach plants have been established and the effect of various cations and the presence of copper cyanide species quantified. It was found that the equilibrium loading of gold was enhanced by the presence of sodium or calcium, with calcium having an order of magnitude stronger effect. The presence of copper has an adverse effect on the equilibrium loading of gold. A unified model was developed to predict the effect of sodium and calcium concentrations in solution and the competitive carbon adsorption of copper on the equilibrium loading of gold on carbon. A satisfactory agreement between the measured gold equilibrium loadings and the model results was obtained over a wide range of solution conditions.

Jan 1, 2010

By E. G. Cauda

Diesel engines are a major source of underground miners? exposure to nitrogen dioxide. In an effort to reduce the exposure of underground miners to regulated and unregulated diesel emissions, primarily particulate matter, mining companies in the U.S. are retrofitting existing and introducing new engines with various exhaust aftertreatment technologies. Different aftertreatment devices, or changing the operating temperature of a selected device, can have unexpected effects on the concentration of nitrogen dioxide emitted by a diesel-powered piece of equipment. This paper provides an overview of the effects different exhaust aftertreatment technologies available to the mining industry have on no2 emissions.

Jan 1, 2010

By D. Leppert

Mr. Garrett brings up several interesting points with respect to the proposed API specification for "nontreated bentonite." However, although not explicitly stated, these specifications are being written based strictly on bentonites from the Wyoming/South Dakota area. Other sodium bentonites may be suitable for use as drill mud but will be unacceptable since the specifications are designed for Wyoming bentonites. Regardless of the API's intent that its specifications are intended only as guidelines, they are generally adhered to on an international basis and, for practical purposes, might as well be chiseled in stone. Estes (1986) notes that the quality of bentonite available from Wyoming producers has steadily declined since the early 1960's. The plastic viscosity: yield point (PV:YP) ratio was included in the current API 13A specification primarily to prevent excessive polymer treatment of lower quality bentonites to make drill mud. However, with development of polymers designed to control YP, this specification cannot ensure that only high-quality bentonites are used for drill mud. Nor will the new specifications for untreated bentonites. Other sodium bentonites are available. Bentonite produced in southeast Oregon demonstrates superior performance characteristics without addition of polymer or other chemicals. However, the exceptionally high purity of these deposits leads to a relatively high YP:PV ratio since the naturally high YP probably results from the higher purity and smaller particle size of this bentonite (Rath, 1986 and personal communication). These bentonites typically have a smectite component exceeding 90% (Rath, 1985), compared with 70% to 75% smectite for typical Wyoming bentonites, as determined by X¬ray diffraction and tests for colloid content. As evident from the accompanying table, the untreated Oregon bentonite has excellent rheological properties, though different from Wyoming bentonites due to the high purity. Additionally, this bentonite reacts well with polymers typically used in the oil industry, making it eminently suitable for use in a low-solids mud system. The extremely low grit content, less that 0.5% on a 75 mm (200-mesh) wet sieve, greatly exceeds the standards set for Wyoming bentonite. Optimum rheological properties are obtained at a higher moisture content than Wyoming bentonites. At 10% moisture, API 13A maximum, the clay is overdried, again reflecting the high smectite content. In summary, the specifications proposed by the API Task Group will ensure that only Wyoming producers can supply "nontreated" bentonite to the oilfield since specifications are

Jan 1, 1989

By E. Bloomstein

The Lone Tree gold mine is located about 4S kilometers east from Winnemucca on the west flank of Lone Tree Hill in Humboldt County, Nevada. The deposit occurs at the north end of the low, rolling Havallah Hills and is about 1 kilometer south of Interstate Highway 80, in sections 11 and 14, Township 34 North, Range 42 East, Mount Diablo Base and Meridian (Fig. 1). The Lone Tree deposit is outside of any previously established mining district and all lands are owned or controlled by Santa Fe Pacific Gold or affiliated companies.

Jan 1, 1993

By D. W. Park

A vast majority of longwall operations in the United States use shield-type hydraulic supports to provide ground control along the longwall face. The three-dimensional finite-element technique combined with a progressive failure approach was utilized to simulate interaction between shields and surrounding strata and determine various loading conditions. In addition, a separate finite element model of the shield structure was made to study responses of each long wall shield to the different loading conditions. Shield responses under various loading conditions and the shield characteristics, such as shield stiffness, the ability of resisting horizontal forces, and the effect of shield height, were studied based on the results from finite-element analyses. The results can provide the basis of effective shield design and be used for evaluation of the shield performance. It is suggested to develop a technique incorporating the finite-element method to evaluate the real-time shield performance for the purpose of effective ground control.

Jan 1, 1992

By M. A. Evanto

Since the late 1970's, the Roof Control Division (RCD) of MSHA's Technical Support has been performing linear analyses for the enhancement of miners' safety. This remote sensing process uses Landsat data to predict areas of potentially hazardous ground conditions in underground mines. To date approximately 700 analyses have been completed by the RCD, with nearly 75 being performed with the current equipment, software and methodology which was updated in early 1995. While success is difficult to measure, requests for linear analyses continue to come from large and small mining companies which suggests the industry's acceptance of the process.

Jan 1, 1998

By N. A. Karl, D. R. Wilburn

"This summary of international mineral exploration activities for the year 2015 draws upon information from industry sources, published literature, SNL Metals & Mining (SNL) (Charlottesville, VA) database and specialists in the U.S. Geological Survey (USGS) National Minerals Information Center. The summary provides data on exploration budgets by region and mineral commodity, identifies significant mineral discoveries and areas of mineral exploration, discusses government programs affecting the mineral exploration industry, and presents analyses of exploration activities performed by the mineral industry.Three types of information are reported and analyzed in this annual review of international exploration: budgetary statistics expressed in U.S. dollars provided by SNL; regional and site-specific exploration activities that took place in 2015 as compiled by the USGS; and regional events that affected exploration activities including economic, social and political conditions, which were derived from published sources and discussions with USGS and industry specialists. Commodity and regional compilations are presented in this summary. Because multiple sources were used to develop commodity and regional compilations, statistics may vary depending on the source and type of data that are being reported.The SNL data summarize planned company budgets for worldwide exploration activities in 2015 for 24 nonfuel mineral commodities and metal alloys and are based on company surveys. Surveys focused on precious metals (gold, platinum-group metals and silver), base metals, (cobalt, copper, lead, molybdenum, nickel, tin and zinc), bulk commodities (bauxite, chromite, iron ore, manganese, phosphate and potash), and other commodities (diamond, graphite, heavy-mineral sands, lithium, niobium, rareearth elements (REE), tantalum, tungsten and uranium).USGS data compilations and analyses are based on information provided by USGS mineral commodity and country specialists, as well as industry contacts and published trade journals. The USGS data summarize exploration site data collected for more than 80 minerals and materials, with a focus on base metals, diamond and precious metals. The USGS analyzed available information to assess the level of exploration activity in 2015 and to report trends in mineral exploration activity for the period 2005 through 2015. These analyses identify where mineral exploration is occurring by commodity and region and the intensity of activity that is taking place in each region for selected mineral commodities, and determines those factors that most affect changes in exploration activity."

May 1, 2016

By Harold F. Yde

Hydraulic tailings fill in the Butte deep level mines was based upon studies made in 1958 by the Anaconda Company Mining Research Department, which published Bulletin No. 35, entitled "Hydraulic Stope Filling". Since then, many things have changed. At the time of the Research Departments study, dry mine tailings were hauled by rail cars from the Anaconda tailings ponds, twenty-five miles distant, to the underground mines' tailings fill plants at the Leonard Anselmo, and Mt. Con Mines. Now, with the installation of the new Weed Concentrator in Butte, tailings is delivered by pipeline to a cyclone at the Kelley Shaft, and stope filling has become more highly automated and streamlined. Presently, mill tailings at approximately thirty percent solids by weight, is pumped from the concentrator, eight thousand feet horizontally and upward, to the Kelley Fill Plant, where they are dewatered and deslimed by three Krebs Model D20B Cyclones, which discharge the material into the cased and grouted mine delivery bore holes at desired densities up to seventy percent solids. The vertical boreholes and four-inch rubber lined Victaulic pipe carry the material downward to horizontal distribution lines, which in turn tap into the stops-filling, three inch, unlined steel Victaulic pipelines. The slurry may travel several thousand feet before it finally discharges into the stope, where it lends support to the mined-out area.

Jan 1, 1969

By F. W. Pereira

The Montana Talc ore body was discovered in the summer of 1983, in the Gravelly Range, approximately 25 miles south of Ennis, Montana. Initial drilling indicated a plus-million-ton ore body of high-purity talc. Preliminary analyses were performed on the ore cuttings, .including chemical analysis, brightness measurements, and microscopic evaluations of the structure of the talc. The results indicated the talc was similar to that currently being marketed from Montana and probably would have good commercial value.

Jan 1, 1989

By William Gleason

Despite a global slowdown in most mining sectors, Caterpillar, the world?s largest mining equipment maker continues to forge ahead with new, and improved offerings to the global mining industry. On Nov. 10, as part of its Loading and Hauling Mining Focus Session at its Tinaja Hills proving grounds south of Tucson, AZ, Caterpillar unveiled to customers and media its two latest mining products, the 994K wheel loader and 6020B hydraulic shovel. The Caterpillar 994K wheel loader builds on a nearly 25-year history of the 994 model but with one noticeable difference ? the 994K is bigger ? much bigger. Weighing in at 239,142 kg (527,218 lb) the 994 K is up to 20 percent larger and comes with up to 30 percent increase in payload capacity. This behemoth of a machine is currently being tested at Caterpillar?s Tucson Proving Grounds, Anglo Gold Ashanti?s Cripple Creek and Victor gold mine in Colorado and Taseko?s Gibraltor copper and molybdenum mine in British Columbia, Canada.

By Diler Katircioglu-Bayel

This study aims to investigate the effect of combined mechanical and ultrasonic milling on the size reduction of talc. Firstly, the talc sample was wet ground in a stirred media mill for five different times (30, 60, 90, 120, and 150 min), and the optimum result was subsequently achieved with treatment by ultrasonication. The effects of amplitude (20, 35, and 50 μm), solid content (2.5, 5, 7.5, and 10%), and sonication time (60, 120, and 240 min) on the sizes of the final product were investigated. The pre-milling by wet grinding caused a decrease in the grinding resistance of talc. Sequential ultrasonic treatment, which was applied to the talc sample, generated smaller particles in comparison to those acquired by stirred media milling alone. Experimental results were assessed based on the product particle size (d10, d50), reduction ratio, and specific energy consumption. Submicron particles prepared by ultrasonic treatment were perfectly stable compared to stirred media milling alone as investigated in terms of particle size. In addition, the effects of mechanical and ultrasonic milling on structural properties of talc particles were characterized by XRD analysis.

By Eleanor Kentish, Nathan Bond, Edward Batty, Simon Webber, Alan Skarda

"Crossrail is Europe’s largest construction project — a new 100km rail route running through central London. A joint venture of BAM, Ferrovial and Kier (BFK) has constructed the tunnels and escalator shafts at the new Bond Street and Farringdon Stations. The recent trend in the UK industry towards sprayed secondary linings is driven by the potential for significant savings in cost and time. BFK is unique within Crossrail by constructing both sprayed and cast secondary linings. This paper presents a direct comparison between sprayed and traditional cast in situ secondary linings at Bond Street and Farringdon Crossrail Stations. An objective comparison is drawn between procurement and mobilisation periods, production rates, flexibility, tolerances and logistics in the tunnels. The technical challenges surrounding cast and sprayed secondary linings are explored, and recommendations are made of how each method could be improved for future use. INTRODUCTION It is well established that sprayed concrete offers a fast and effective method to seal the face of an excavation. In a relatively short space of time, sprayed concrete can be applied to an open face to support the short term ground loading on the tunnels during construction. Advances in sprayed concrete lining (SCL) technology — such as the use of wet mix processes, improved accelerators, fiber reinforcement, remotely controlled spraying robots, innovative surveying equipment and nozzleman competency schemes — have greatly increased the speed and safety of tunnel excavations using this technique. As a result, design engineers have become increasingly confident to use SCL primary linings as part of the permanent structural lining (Su 2014). Historically, long term ground and water pressure loads have been considered to be carried by the main structural or secondary lining, constructed using cast in situ concrete (Pickett 2014). However, the advances described above have made sprayed secondary linings a viable option, which has already been proven on the A3 Hindhead Tunnel (Arnold 2012). Sprayed concrete secondary linings offer potentially significant savings in cost and time during the construction process. The contractor does not need to procure a bespoke formwork system for each different sized tunnel — the SCL plant required is already on site for the primary lining. Each bay is sprayed with accelerated concrete, becoming self-supporting almost immediately — compared to moving and resetting the shutter, pumping concrete and waiting for it to cure. With sprayed concrete, working sequences and cross sections can easily be changed."

Jan 1, 2016

By N. A. Karl, D. R. Wilburn

"This summary of international mineral exploration activities for the year 2016 draws upon information from industry sources, published literature, SNL Metals & Mining (SNL), an offering of S&P Global Market Intelligence (New York, NY), and specialists in the U.S. Geological Survey (USGS) National Minerals Information Center. Three types of information are reported and analyzed in this annual review of international exploration: 1) budgetary statistics expressed in U.S. dollars provided by SNL; 2) regional and site-specific exploration activities that took place in 2016 as compiled by the USGS and 3) regional events and legislation that affected exploration activities including economic, social and political conditions, which were derived from published sources and discussions with USGS and industry specialists. Commodity and regional compilations are presented in this summary. Because multiple sources were used to develop commodity and regional compilations, statistics may vary depending on the source and type of data that are being reported. The SNL data summarize budget estimates for worldwide exploration activities in 2016 for 30 nonfuel mineral commodities and metal alloys, based on company surveys. Surveys focused on precious metals (gold, platinumgroup platinumgroup metals (PGMs) and silver), base metals, (cobalt, copper, lead, molybdenum, nickel, tin and zinc), bulk commodities (bauxite, chromite, iron ore, manganese, phosphate and potash) and other commodities (aluminum, antimony, diamond, graphite, heavy-mineral sands, lithium, niobium, rare-earth elements (REEs), scandium, tantalum, tungsten, uranium, vanadium and yttrium). Information on uranium exploration activities was included in SNL’s survey for the first time in 2007. Data on lithium, niobium, phosphate, potash, REE and tungsten were compiled for the first time in 2010, and scandium, vanadium and yttrium were added in 2014 because of their increased topical significance. Since 1999, companies with exploration budgets of $100,000 and greater were included in the SNL surveys. SNL budget estimates exclude coal, and oil and gas. The 2016 SNL mining company survey compilation was reported by SNL to include an estimated 95 percent of the world’s nonfuel mineral exploration budgets. The 5 percent that was not covered was accounted for by companies that chose not to participate in the SNL survey, private companies that do not publish their budget data and government-funded exploration activities."

Jan 5, 2017

Reaction kinetics for gold dissolution in acid thiourea solutions were investigated using formamidine disulfide as an oxidant. For the conditions studied it appears that a surface reaction limits the rate of gold dissolution. The rate was found to be first order with respect to thiourea concentration and half order with respect to the concentration of formamidine disulfide; the apparent activation energy for the reaction was 10.40 kcal/mol (43.40 kJ/mol); and the reaction rate was independent of pH for the pH range 1.0 to 3.0.

Jan 1, 1999

By A. B. Cecala

An evaluation was recently performed on a district recirculation system at a trona mine in Granger, Wyoming. A 1.52m (5 ft) diameter, 37.3kw (50 hp) vane axial fan was installed in a crosscut between the intake and return airways and recirculated approximately 31.4 m'/sec (66,578 ft'/min) of air back into the intake. This amounted to a recirculation factor of approximately 20 pct of the return air. This air was part of the primary ventilation to three different continuous miner sections at operating distances of between 6l0m (2,000 ft) and 1,829m (6,000 ft) from the recirculation fan. The mine environment was constantly monitored for respirable dust, methane, and carbon monoxide in the operating sections and in the main intake and return entries. In addition, air samples were taken with and without the recirculation system during the evaluation and analyzed using gas chromatography. The results of this study showed only small increases in dust, while all other mine contaminants remained at such low levels that it was impossible to determine any relative changes from the recirculation system. Because of this, a brief SF. tracer gas analysis study was subsequently performed to more precisely determine an increase in a mine contaminant with the recirculation system.

Jan 1, 1991

By Baojie Zhang

The main goal of this study was not only to investigate the effectiveness of the FGX Dry Separator for removing pure rock from run-of-mine coal producing a better feed stock for conventional coal preparation plants but also to optimize the FGX Dry Separator performance for producing a salable clean coal product without using the conventional wet coal preparation processes. A Model FGX-1 Dry Separator with feed throughput capacity of 10 tph was extensively tested at the Illinois Coal Development Park using two coal samples having distinctly different cleaning characteristics. Statistically designed experimental programs were conducted to indentify critical process variables and optimize FGX Dry Separator performance by systematic adjustments of critical process variable parameters. The coal cleaning performance of the FGX Dry Separator was evaluated for the particle size range of 63.5 x 4.76 mm in most cases, although FGX Dry Separator feed consisted of nominal -63.5 mm run-of-mine coals. The best cleaning performance obtained from the FGX Dry Separator is described by specific gravity of separation (SG50) and probable error (Ep) values of 1.98 and 0.17, respectively. The SG50 and Ep values for individual size fractions were as follow: 1.90 and 0.12 for the +50.8 mm size fraction, 1.95 and 0.18 for the 50.8 x 25.4 mm size fraction, 2.01 and 0.19 for the 25.4 x 12.7 mm size fraction, and 2.03 and 0.23 for the 12.7 x 4.76 mm size fraction. These process efficiency measures produced a clean coal with ash content of 13.38% from a feed coal with ash content of 34.45%. Ash content of tailings and middlings streams were 85.09% and 39.57%, respectively. Total sulfur contents of corresponding streams were 3.87%, 4.68%, 6.87%, and 4.62%. For a relatively easy to clean Illinois No 6 seam coal (Cleaning Index: 0.72), only about 0.42% of the clean coal (i.e., 1.6 float fraction) present in the feed was lost to the tailings stream. For a relatively difficult to clean coal (Cleaning Index: 0.53), about 0.98% of the clean coal present in the feed was lost to the tailings stream.

Jan 1, 2012