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By K. F. Unrug

Martin County Coal Corp. is located in Martin County, KY, in the Appalachian coal fields, near the West Virginia border. The company's total leasehold covers more then 133.5 km' (33,000 acres). Total annual production at Martin County Coal Corp. is currently 2.2 Mt (2.5 million st). In certain years, though, it exceeded 2.7 Mt (3 million st). About 45% of the annual production comes from two surface mines. The balance is produced from five underground mines. Martin County Coal's work schedule consists of two nine-hour shifts a day, 240 days a year. Topography The topography of the area is characterized by rugged hills and ridges and sharp V-shaped valleys demonstrating a cliff and slope topography. This topography consists of alternating benches of outcrop sandstone and slopes. The deep valleys have been carved out by many small streams in the area. These streams are contained within the steep slopes of narrow, twisted mountain ridges. The ridges are underlain by massive sandstones that, being resistant to erosion, create sharp, rocky morphology. The height of the hills above the valley floors ranges from 122 to 244 m (400 to 800 ft).

Jan 1, 1991

By Charles N. Alpers, Jane M. Hammarstrom, Robert R. II Seal, Nora K. Foley

Geoenvironmental models are compilations of geologic, geochemical, and hydrologic information that describe both the pre- and post-mining environmental signatures of mineral deposits. The environmental behavior of seafloor massive sulfide deposits varies according to deposit type. This study has divided massive sulfide deposits into six categories: (1) Noranda-type, (2) Kuroko-type, (3) Cyprus- type, (4) Bathurst-type, (5) Besshi-type, and (6) sedimentary-exhalative deposits. In addition to Fe and Al, the heavy metals most commonly associated with drainage from these deposits are Cu, Zn, Cd, Pb, and As. Metal ratios of mine drainage and natural background waters tend to reflect the primary character of the ores. Variations in pyrite and pyrrhotite contents are reflected in lower pH values associated with pyrite-rich deposit types.

Jan 1, 2000

By J. P. Hedlund

Molycorp's gravity type panel-caving operation employs a system of short raises to transfer ore from the Grizzly Level to the Haulage Level. The raises have normally been developed using a conventional drill-and-blast method or a combination conventional/raiseboring method. A new method was needed that would be less labor intensive, provide a safer work environment for personnel, provide a stable raise that could be self-supporting and a method that would be cost competitive with the conventional system.

Jan 1, 1991

By Richard R. Klimpel

This paper discusses the use of froth flotation as a means of removing metal containing species from a variety of feed streams that generally fall into the classification of waste streams. The variability in solid composition, degree of oxidation, water chemistry, and levels of organic/inorganic contaminants associated with waste streams implies that the collector chemicals used in any flotation process must be much more selective than typically required in normal mineral ore flotation systems. Several examples of such work currently underway will be illustrated showing the potential of flotation to upgrade metal-containing waste streams.

Jan 1, 1992

By Richard Switalski, Mark R. Kritzer, Boro J. Lukajic, Robert Pintabona

Ground freezing was chosen as an initial support method during construction of two deep shafts at the Mill Creek project. The Mill Creek, Phase 2 tunnel (MCT-2) is utilized to convey and store combined storm and sanitary sewage collected from the member communities in the greater Cleveland area. The main objective of groundfreezing was to provide a strong support structure to resist soil and groundwater pressures. This was achieved by creating a watertight, frozen-ground barrier around the shaft perimeter. The paper will provide an overview of ground freezing techniques applied during the construction of two shafts, each 250-feet deep.

Jan 1, 2003

By K. Soucek

Extraction of hard coal reserves, but also of mineral resources in general in the underground coal mines includes in itself many anthropogenic interventions in the earth crust. These interventions are closely associated with the solution of stability problems in the mine and with occupational safety. One of potential applications of such geo-technical interventions in rock mass is the chemical grouting technology. The chemical grouts are very suitable to affect the physical and chemical properties of rock mass. With the present development of chemical grouts, primarily based on polymers, there come into existence new composite materials during the grouting process (the so called geo-composites), which properties significantly differ from the original rock. An important factor, which affects a choice of chemical grouts and at the same time the effectiveness of grouting technology is the resulting properties of geo-composites. The properties of a coal geo-composite differ from the ones of the unmodified coal seam. On the basis of the laboratory geo-mechanical tests, the differences of properties of both material types were found. While the pure coal samples were destroyed very brittle and explosive, the geo-composite samples were making higher level of tenacity and load bearing ability after overstep of material strength. The presented paper discusses the different behaviour of these original and modified coal samples. The X-ray CT scans were used for observation and demonstration of failure evolution in these samples of pure coal and coal geo-composites after compressive loading.

Jan 1, 2006

By Catherine T. Aimone

A computerized cost model has been developed to simulate the technical and economic effects of strip mine blasting in the vicinity of structures. Current surface mining regulations restrict the allowable level of production blasting as a function of this distance. Blast design modifications,' therefore must be employed when blasting in the vicinity of homes to ensure compliance with federal and state regulations specifying limits to the seismic effects generated from a blast. The blasting level allowed. is computed by the charge weight of explosives per delay from the following scaled distance formula: [ ] where W is the charge weight per delay, in kilograms (pounds), D is the distance factor corresponding to the regulatory limit of peak particle velocity to which a structure may be subjected to. Current regulations specify 2.54 cm (1.0 in.) per second corresponding to a SD factor of 27 (60) (Federal Register, 1977).

Jan 1, 1982

By Harry M. Edenborn, Richard W. Hammack

Experiments were done to determine if a mushroom compost-based sulfate reduction system could be used to treat nickel-contaminated mine waters. Sulfate reduction systems were established in columns containing acid-washed mushroom compost. Simulated mine waters containing 2000 mg/L sulfate and 50 to 1000 mg/L nickel were adjusted to pH 4.5 and pumped through the columns at flow rates between 15 and 25 mL/hr. During the first nine days of operation, virtually all influent nickel was removed in the columns by sorption and ion exchange mechanisms. The nickel removal rate then dropped to 18 to 30 mg Ni/day (7.8 to 12.8 nmol/ g-substrate/day), probably due to low sulfate reduction rates. When sodium lactate was added to the inflow, a sustained and seven-fold increase in the nickel removal rate was observed. Bacterial sulfate reduction rates measured in mushroom compost-based wetlands exposed to coal mine drainage are 2 to 20 times faster than the rates observed in this study. Low sulfate reduction rates in the columns may have been due to the inhibition of microbial activity by high nickel concentrations and the removal of labile organic compounds from the mushroom compost substrate during acid-washing. Results of this study indicate that bacterial sulfate reduction can effectively treat nickel concentrations up to 500 mg/L if labile carbon is nonlimiting.

Jan 1, 1992

By D. W. Horsfall

The different types of processes used in fine coal beneficiation in the Republic of South Africa are listed, together with data giving an indication of their separating efficiencies The two classes of coal, fines and ultra-fines, present in the -0,s m fraction of the run of mine coal are discussed, with special reference to their beneficiation characteristics. Using those properties, together with the data on plant efficiency, case studies are worked out to indicate the advantages and disadvantages of the different processing routes available. The paper closes with an indication of areas where research is required to enable some of the processes to be applied to a greater extent than is presently the case.

Jan 1, 1988

By M. G. Hester, G. S. Adisoma

To address the problem of grade estimation in a general three-dimensional shape and the uncertainty associated with the estimate, the technique of jackknifing/ block-kriging shortcut is proposed. A new estimator called jackknife kriging is introduced first. Through the jackknife variance, a confidence limit for the reserve-grade estimate can be calculated. Unlike the kriging variance, which is more a measure of data configuration and which is independent of data values, the jackknife variance reflects the true variability of the data. This approach provides a simple way to set a confidence level for global estimation of resources.

Jan 1, 1997

By R. J. Wahrer

In 1996, the Office of Surface Mining (OSM) and the U.S. Fish and Wildlife Service (FWS) completed an Endangered Species Act (ESA) programmatic Section 7 consultation. From the resultant Biological Opinion, it was found that coal mining operations conducted under federally approved state regulatory programs would not likely jeopardize the continuation of federally listed species nor result in the destruction or adverse modification of critical habitats. The requirements of the ESA and their integration into the SMCRA permitting process and the responsibilities of the regulatory agency, the FWS and the coal operator will be discussed. Guidance on the development of protection and enhancement plans will be provided and site-specific examples given.

Jan 1, 2003

By H. G. Linge

Pyrrhotite (FeS1+x ,0<x<0.15) is an iron sulfide which is considered to be a pest in carbon-in-pulp/ leach (CIP/L) gold processing [l].The perceived influence of pyrrhotite on gold processing by CIP/L is a competing consumption of 02 and CN­as the pyrrhotite dissolves by oxidation [1,2]. The few studies of the oxidation chemistry, kinetics and mechanism of the oxidation ofpyrrhotite are reviewed in detail elsewhere [3].There is broad agreement that the surface of pyrrhotite is very rapidly oxidized to form a thin (e.g. 10 nm) ferric hydroxy-oxide layer which overlays an iron-deficient sulfide lattice covering the original pyrrhotite. The reaction can be summarized thus:

Jan 1, 1995

By Daniel W. Kappes

In late 1995 at the Randol symposium in Squaw Valley, I gave a paper which described the Itos project flowsheet. At that time, project construction was nearly completed and stmtup was close. This paper describes the ltos operation since then. To summa­rize things, startup occurred partially in late 1995 with full start­up of all components in about mid 1996. From then until now, April 1998, the plant has been running at partial capacity and has yet to achieve full production rates.

Jan 1, 1998

By A. H. Reitsema, Hans E. van Dam

In CIP, CIL, and Heap Leach gold recovery operations, a sub-optimal activated carbon performance invariably causes a significant loss of revenues. In this paper it is shown, how dedicated analyses of carbon samples can be used as a guide in plant performance optimiza­tion. Firstly, a brief outline is given of the most important methods of analyses, including the specialized methods not normally used by mining operations, but provided by carbon manufacturers. Then, a number of practical cases are discussed in which carbon sample analyses provided insight which allowed significant improvements.

Jan 1, 1995

By H. R. Cooper

Refinements and increased sophistication in modeling and simulation, and introduction of advanced techniques in automatic control made feasible with digital processor handling of data, represent the most significant fields of advancement during the past ten years. Extensions in capability to predict performance of beneficiation and other mineral extraction techniques now provide powerful assistance to developers and and designers of minerals processing unit operations and complete plant flowsheets. Computer aided advances are categorized by work in the following fields: - Steady state modeling and simulation of processes - Dynamic modeling and simulation of processes - Optimization methodology in crushing, grinding, and flotation - Optimal process control methods - Expert systems in process control

Jan 1, 1989

By Jim Salley, Mohammad Saleem, Indra Banerjee, Kevin Sapp

"On underground construction projects, effective Quality Management is essential for ensuring facility durability, life cycle performance and low maintainability. Furthermore, follow on contracts also rely on an effective quality management system for interface congruency. An effective Quality Management System (QMS) is also essential in mitigating risks and meeting schedule and budget performance objectives. For the past 15 years Central Puget Sound Regional Transit Authority’s Link Light Rail extension has successfully completed over 10 miles of twin bore tunneling and associated underground features including cross passages, deep sump structures and shafts. After the completion of each segment, lessons learned have successfully been implemented to improve the quality of delivered projects. This paper presents the Sound Transit QMS with regard to a number of project elements of tunnel construction projects, with specific focus on quality performance of slurry wall construction, TBM tunnel excavation assessment, segment production and segmental lining installation, and other associated construction features. A collaborated total QMS will be presented in this paper that will serve as a guide for successful implementation of Quality Assurance and Quality Control processes. INTRODUCTION Implementation of a robust Quality Management System reduces defects, errors and omissions, identifies and addresses nonconformance in a timely manner and increases stakeholder confidence in the project. In fact and effective QMS helps ensure that optimal project outcomes are realized both in terms of project delivery and life cycle performance. The two key components of QMS are quality control and quality assurance. Quality Control (QC) is the procedure implemented to achieve a certain level of quality and ensure that products, processes and services meet specific requirements. Quality Assurance (QA) activities are carried out to evaluate the effectiveness of the quality control measures and ensure that the QC process is working. A team obligation that recognizes that quality is built into every aspect of a project is the basic concept of a successful QMS."

Jan 1, 2016

By J. Katzur

Recently in Germany, novel artificial humus in combination with water-storing hydrogels has successfully been tested as soil improving material in pot experiments. The novel artificial humus (NOVIHUM®) is derived from lignite through oxidative ammonolysis. The product contains c. 5.5% nitrogen. Using NOVIHUM® as fertiliser, variable amounts of the contained nitrogen are gradually available to the plant, depending on the hydrolysis rates of the different N-compounds. NOVIHUM® is a unique combination of long-term fertiliser and stable humus. The tested hydrogel is a polyacrylate/poly-amide copolymer, which is able to improve the water holding capacity of the soil and to retard significantly desiccation. In May 2000, in Germany (Aue region), an experimental site was set up under extremely difficult growing conditions for trees (Quercus petraea) on a uranium spoil pile of the mining company WISMUT Ltd. The oak plots treated with NOVIHUM® and hydrogel showed increased total increment-values, which mainly are the result of the second growth phase. Obviously, these plants profit from the favourable physical parameters of the substrate and the use of the novel artificial humus as nitrogen source. The oak trees can better use the plant-available NH4-nitrogen released from the artificial humus during the planting year. In Greece, an experiment was set up in December 2000 aiming to the afforestation (Pinus nigra, Abies cephalonica) of a bauxite spoil pile of SILVER & BARYTE ORES MINING Co. S.A., on the Parnassus Mountain. The scope was to demonstrate, that the above soil improving materials are also appropriate for the recultivation of sites under extreme climatic and orographic conditions. The first results revealed, that where NOVIHUM® and hydrogel were combined, plant growth was greater than the average. The one-year results of the experiments fulfil our expectations concerning the application of NOVIHUM® in combination with hydrogel for the afforestation of problematic sites, such as the south-exposed steep slopes of the spoil piles of uranium mining. They may represent the most detrimental sites for afforestation in Europe.

Jan 1, 2002

By T. G. P. Vasquez

The elimination of metal ions from aqueous solutions by biosorption plays an important role in water pollution control. Heavy metals are hazardous to the aquatic ecosystem and pose possible human health risk. Beside the toxic and harmful effects to organisms living in water heavy metals also accumulate throughout the food chain and may affect human beings. Conventional methods for removing metals from aqueous solutions before they are disposed of include chemical precipitation and sludge separation, chemical oxidation or reduction, ion exchange, reverse osmosis, electrochemical treatment, and evaporation. Alternative processing methods are being considered more seriously. Sorption and/or complexation of dissolved metals species based on the chemical activity of biomass, known as biosorption, is the base of the new technology for metal removal and recovery. Different types of biomass (dead and alive) have been investigated for biosorption of heavy metals ions. In the present work, the cadmium biosorption capacity and bioflotation of Rhodococcus opacus were studied. The adsorption capacity of biomass was investigated by batch experiments, the influences of some variables like pH and ion concentration were evaluated and the experimental data obtained for each metal were evaluated and fitted using adsorption and kinetic models. The bioflotation process showed that R. opacus has excellent features as collector and foaming agent after metal biosorption. Around 90% of cadmium uptake by the biomass was achieved by bioflotation.

Jan 1, 2006

By A. Dale Wunderlich

In the past, most people have associated gold scams with the sale of non-existent gold mines, an undivided interest in unmined ore or the sale of gold-plated lead bars. These scams are still available to those who want to speculate. Now, though, the mining industry is plagued with a new type of con artist. Many of the new scams involve large, well established mining companies being victimized. Nearly all legitimate mining companies are in search of good mining prospects. This makes them susceptible to modern day con artists. Many professionals from the mining and petrochemical industries are out of work. Some of them have gotten involved with scams or activities that border on the criminal. Mining companies are losing millions of dollars each year to scams. Some of these scams involve venture-capital fraud. Some involve fraudulent mining proposals. And some involve unqualified individuals who are providing services by the precious metals industry. The author estimates that mining scams may be costing precious metals companies as much in dollar losses annually as employee theft. Employee theft is at an all time high, but so are gold scams. Since January of 1990, the au¬thor has been involved in gold theft investigations in which more than $1 million in gold product has been stolen by employees. In the past, most of the gold mine scam operators have concentrated on the general public, which is generally ignorant of basic mining procedures and practices. A scam artist would tell someone from your neighborhood that they have a wonderful underground mine. It produces 62.2 kg/t (2000 oz per st) of gold ore. Your neighbor might think that sounds like a very good investment. Those involved in the mining industry know better.

Jan 1, 1990

By S. K. M. Chao

The increasing demand for large volumes of relatively low-cost cement has resulted in the need for an equally low-cost high-volume means for transporting that cement. It has been estimated that 20% - 25% of the total cost of cement to the buyer represents delivery expenses from the mills. For instance, during the 1972 cement shortage in the Southeastern region of the U. S., bid prices for a ton of cement delivered increased to $45 compared to $20 average at mill price, i. e. , F. O. B. plant. Much of the increase was caused by the anticipated higher cement shipping costs for longer hauling distance. The exceptionally high bid price, of course, was not the price quoted by the successful bidder. Thus, clearly, cement is not a marketable commodity unless it can be economically transported to the consumer.

Jan 1, 1975