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By Jeff Schwoebel, Arcy, D&apos Horner

The Deep Coal Seam Project is a multi- year, large-scale research and development effort between the Gas Research Institute (GRI) and Resource Enterprises, Inc. (REI). The project is being conducted at the Red Mountain Site, a multi-well test site located in the southeastern portion of the Piceance Basin near Collbran in Mesa County, Colorado. The project objective is to develop the drilling, reservoir evaluation, completion and production technology required to produce gas from a thick, deeply buried coal seam. To understand the parameters controlling gas production, project efforts are focused on the Cameo "D" coal reservoir which lies at a depth of about 1707 m (5,600 ft) at the test site. This paper overviews the drilling, testing, completion, and production techniques used on the 1, 2 and 3 Deep Seam wells and implications for resource development.

Jan 1, 1987

By Kenneth N. Han, Xinghui Meng, A. J. Monhemius, G. W. Warren, E. Peters

The leaching of gold in ammoniacal solutions containing various oxidants in an autoclave has been investigated. Also studied are thermodynamic and kinetic aspects of the ammonia leaching of gold and silver. The variables studied included stirring speed, temperature, concentration of ammonia, ammonium, and various anions. Arrhenius activation energy values were found to be between 47.1 kJ/mol and 86.2 kJ/mol depending upon the kinds of oxidants used. An electrochemical reaction controlling mechanism has been proposed for the dissolution reaction. The leaching behavior of gold and silver from various ores in ammoniacal solutions containing various oxidants has also been investigated. The samples tested included sulfidic as well as carbonaceous refractory ores. The recoveries of gold and silver from these refractory ores were better than 96% within 2-3 hours of leaching time.

Jan 1, 1993

By Z. F. Wang, W. K. Choi, A. E. Torma

The present study has investigated the bioleachability of low-grade and high-grade pyritic gold ores and the extraction of gold from the leach residues of bioleaching with thiourea solutions. Final gold extractions as high as 96% were obtained from the high-grade ore and above 93% from the low-grade ore. The gold extraction was found to follow the extent of pyrite biooxidation. Using a cyclic voltammetric technique and carbon-paste-FeS2 electrode it was found that the semiconductor pyrite oxidation involves many intermediate electrochemical reactions. Furthermore, the oxidation is solid-state diffusion controlled as suggested by chronoamperometric and chronopotentiometric measurements.Using Sand's approach, the activation energy of solid-state diffusion biooxidation of pyrite was determined to be AEa=22.4 kJ. A generalized model for the mechanisms of pyrite oxidation has been presented.

Jan 1, 1990

By M. Josick Comarmond, John J. Jeffery, John W. Bennett

Oxidation rates of sulfidic mine wastes measured at a range of size scales have been collected from a number of sources. The results suggest that well-designed laboratory columns, under controlled conditions, provide comparable information on oxidation rates to that obtained from field test piles. It has been found in the cases presented that laboratory measurements of oxidation rates of a particular material type can be applied with confidence to the same materials in the field. It is recommended that a further study be undertaken to measure the time-dependence of the oxidation rate for a range of particle sizes and different materials. This study would provide measurements against which models of oxidation rate as a function of time and particle size can be tested, to give confidence in the use of models to describe dump behaviour in the longer term.

Jan 1, 2000

By G. T. Adel

As a prerequisite to removing mineral matter from coal by any physical separation technique, the mineral and coal particles must be sufficiently liberated. In the case of the production of superclean (< 2% ash), low-sulfur products, the appropriate liberation size may be less than 10 µm. Unfortunately, much of the liberation data obtained at these fine sizes is only qualitative due to the lack of appropriate instrumentation. In the present work, computerized image analysis has been used to characterize several common eastern U.S. coals. In most cases, it has been found that micronizing of the coal is necessary in order to achieve sufficient liberation for deep cleaning. Liberation analyses of the products from the microbubble column flotation process have been used to distinguish problems in liberation from problems in selectivity, especially as they pertain to pyrite rejection.

Jan 1, 1989

By R. V. Ramani, S. Tan

A computer-oriented systems simulator (CMHS) has been developed for analysis of continuous materials handling systems. Special emphasis has been placed in the model on several features that are unique to these systems. These features include periodic pattern of material arrival from several sources, several types of material to he transferred, material dispatch processes, intermediate storage capacities, and multiple material destinations. Both the deterministic factors of the continuous material handling system, such as the physical decomposition of the system and the scheme and schedule of its operation, and the stochastic factors, such as variations of material arrival, material pattern on the conveyor, and availabilities of the system elements, are considered in the simulator. The application, of the model is demonstrated through a study of an underground conveyor belt network serving long- wall and continuous miner sections.

Jan 1, 1990

By T. Ko, K. N. Han, C. S. Park, N. S. Kim, C. Yoon, H. Yoon

Quantitative analysis of Platinum Group Metals from ore samples and industrial materials using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS), Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES), Atomic Absorption Spectrometer(AAS), and X-ray Fluorescence (XRF) techniques was conducted and the performance of various techniques was compared. The effects of different matrices in the sample materials were compared and discussed for each analytical technique. The ICP-AES technique exhibited better accuracy than AAS but showed limitations in its application due to strong spectral interference in the presence of common matrix elements such as iron. The ICP-MS showed the lowest detection limit and less spectral interferences than the previous two techniques. The XRF technique was also applied to examine the total amount of PGM from industrial materials. Results from each analytical method on various sources were presented and discussed.

Jan 1, 2003

By S. E. Phifer

The Haile gold mine was the largest gold producer east of the Mississippi River before 1942. It was the first gold mine in the Southeast to reopen following deregulation of the gold price by the United States Government. The Haile mine was also the first gold mine in the Southeast to use heap leaching and carbon recovery for gold production. Current production involves mining and heap leaching about 1.8 kt/d (1600 stpd). Carbon is used as a recovery medium. Due to the clay and excessive fines in the oxidized ore, agglomeration using portland cement is required before leaching. Agglomerated ore ranges in screen size from 50 mm (2 in.) to less than 75 µm (200 mesh). The agglomerating step combined with certain other conditions has enabled Piedmont Mining Co. to achieve recoveries of about 90% or better.

Jan 1, 1987

By R. S. Sheeta, C. J. Bise

The search for a more effective means of coping with methane liberation has resulted in the expanded use of seam degasification. Its advantages are measured not only in reducing the hazards due to methane, but also in producing a marketable commodity, the gas itself. However, the success of a methane drainage system is the culmination of many complex factors, the most important being the coal seam permeability. The two most popular drainage techniques used in mining today are the vertically stimulated borehole method and the in-seam horizontal borehole method. The objective of this paper is to determine the permeability range in which the selection of the degasification technique is based primarily on equipment and economic analysis. A discussion of the equipment involved will be incorporated into examples evaluated by the Pennsylvania State University coal methane simulation model.

Jan 1, 1990

A series of laboratory based push and pull tests were carried out to investigate how surface profile influence the load transfer mechanism of bolt/resin interface. Tests were carried out in both 75 mm and 150 mm long steel sleeves. Three types of bolts were examined, they were bolts most commonly used for strata reinforcements in underground coal mines in Australia. The bolts had near equal core diameter but of different profile configurations. The change in the length of the encapsulation sleeve was examined in light of the small number of profiles encapsulated effectively in short 75 mm long sleeves. The results showed that peak loads and displacements were directly related to the height and the spacing of the bolt surface profiles. Profile spacing appears to have greater influence on load transfer capacity than the profile height.

Jan 1, 2006

By M. G. Rylatt

BHP Diamonds is developing Canada&apos;s first diamond mine, Ekati, located in the Northwest Territories (NWT). The mine is a joint venture between manager and operator BHP (51%), Dia Met Minerals (29%), Charles Fipke (10%) and Stuart Blusson (10%). BHP Diamonds is part of BHP Minerals: Production at Ekati began Oct. 14,1998. The mine is situated on a 3,450-km2 (853,000-acre) claim block located in the Lac de Gras region of the NWT (Fig. 1). It is about 300 km (185 miles) northeast of Yellowknife and 100 km (60 miles) south of the Arctic Circle. The seasonal winter ice road to Echo Bay&apos;s Lupin Mine passes along the eastern margin of the project area. This allows road access each year from mid-January to mid-April. For the remainder of the year, the project is accessible only by air.

Jan 1, 1999

By Winfield G. Wright, Greg P. Meeker, Philip L. Verplanck, Douglas B. Yager, Dana J. Bove, M. Alisa Mast

A really extensive acid sulfate-altered and mineralized rock in the southeast Red Mountains area is noted for its association with naturally occurring and mine-related acidic and metal-rich waters. Integrated geologic and aqueous geochemical studies demonstrate that the degree of metal mobilization and acid production in natural waters correlates well with the type of hydrothermally altered rock and structural features in which these water interact. Quartz-sericite-pyrite, quartz-alunite, and argillic alteration assemblages are associated with some of the most naturally acidic, high-metal waters in the study area; calcite-bearing propylitic rocks are related to the most pristine waters and buffer sulfate-rich, acidic waters produced by pyrite oxidation. Trace metals in natural waters are mostly derived from enargite, zinc-rich tetrahedrite and sphalerite. Pyrite oxidation contributes very little with respect to base-metals in these natural waters.

Jan 1, 2000

By Graham A. Mathieson

A detailed breakdown of capital and operating costs is an essential element in the planning and evaluation of any mining project. The OPCOST System was developed by Golder Associates to provide mining engineers with the facility to synthesize detailed cost estimates for all aspects of an operating or potential open pit mine. The system can also be applied to underground mines equally as well. Such estimates can be prepared at a variety of levels depending on the detail required by the project. The OPCOST System is a suite of computer programs linked through a common hierarchical data base. It simulates the thought and reasoning processes within the quantity takeoff and cost estimation phases of a mining project. The system was developed as a mining cost engineering tool on the basis that it would have to satisfy a variety of purposes, namely:

Jan 1, 1982

By Hans von Michaelis

Gold metallurgy has advanced remarkably over the last decade. Even more significant progress will be made over the next five years, particularly in the application of advanced comminution techniques and control, preconcentration (flotation, ore sorting and coal gold agglomeration), enhancement of cyanide leaching technology, non- cyanide leaching, treatment of refractory ores and concentrates, and improved recovery systems. Carbon adsorption processes have become standard practice for ores with relatively high gold/silver ratios, but ion exchange potentially offers distinct advantages and has recently been demonstrated to perform better in at least one application. Even in the established zinc precipitation and CIP processes several important practical improvements are emerging as experience is gained at the ever increasing number of operating plants. Improved process control and reduction of reagent consumption costs are two important goals of industry at this time.

Jan 1, 1989

By R. Woods, O. A. Kiehn, C. A. Born, F. N. Bender

Development of the flotation reagent scheme at Climax Molybdenum Company&apos;s mine at Climax Colorado is reviewed. Features of the mineralogy, milling practice and background of reagent changes are outlined. Special attention is given to the hitherto unpublished details of the application of depressants for copper and lead impurities. The present rougher flotation reagent scheme utilizes a neutral hydrocarbon oil, low in unsaturates and wax, as collector with a sulfated coconut oil emulsifier and pine oil frother. Lime and sodium silicate are used as rougher conditioning and slime dispersant agents. Chalcopyrite and galena impurities are de- pressed in both rougher and cleaner plants by stage addition of Nokes reagent and sodium cyanide to yield a metallurgical grade molybdenite concentrate containing greater than 90% molybdenite and less than 0.5%, 0.1% and 0.05% iron, copper and lead impurities, respectively.

Jan 1, 1976

By K. Kavouridis

On 30 April 2004, a large scale slope failure incident occurred at the external waste dump facility of the South Field Mine, in the Western Macedonia Lignite Center, Greece. This landslide involved the mobilization of waste overburden material (that was continuously deposited for the last 20 years) in the order of 40 Mm3, while the material that moved outside the boundaries of the waste dump was in the order of 3 Mm3. The factors that led to failure as well as the procedures and measures taken in order to stabilize the failure and resume normal operations at the South Field Mine are presented and discussed. Emphasis is given to the impact on mine operations and the cost related to resuming of normal production operation as well as to implementing important modifications and improvements of the materials handling system.

Jan 1, 2006

By N. Zouridakis

Radon is an established lung carcinogen and remains the most important environmental radiation exposure. It was estimated that inhalation of radon and its short-lived decay products accounts on average for about one half of the effective dose equivalent from all natural sources of radiation. Radon contained in household water can transferred into room air as a result of agitation or heating. An indoor air concentration of 400 Bq/m3 is obtained if the radon concentration in household water is 4 kBq/L. A typical concentration of radon in ground water is about 1000 times lower than this concentration but sometime elevated concentrations of some kBq/L in ground water are reported. In this work a Liquid Scintillation counting system is used to obtain fast and accurate measurements of radon (222Rn) in water samples from Argolida, Greece.

Jan 1, 2007

By Scott G. Britton

Traditionally, water removal has taken a backseat to many other coal mining functions. However, it is a vital part of the total mine support system. In many US coal mines, more tons of water are removed each year than tons of coal. An excellent discussion of general drainage characteristics can be found in Chapter 8 of Elements of Practical Coal Mining, published by SME-AIME. This chapter is organized into three major sections. These are: designing effective drainage systems; constructing the main mine pumping station (static system); and constructing a portable pumping station (dynamic system). Each topic presents a separate discussion of the elements a construction foreman or engineer should consider for effective installation and operation of the mine drainage system. In addition, a list of pumping equipment manufacturers is available to interested persons and follows these sections.

Jan 1, 1983

By W. Ghyoot, J. Boonstra, H. Dijkman, C. Buisman, M. Picavet

Paques and Umicore have demonstrated the feasibility of biological treatment of the highly complex Hoboken wastewaters in a1 m3/h pilot plant at Umicore Precious Metals, Hoboken, Belgium. In the first step arsenic was precipitated from copper smelter effluent as As2S3using biogenic produced H2S. Other metals such as copper, lead and cadmium were also removed as MeS to concentrations well below the discharge levels. Subsequently, sulfate and nitrate were removed to low concentrations (<300 mg/l and < 5 mg/l respectively) in high rate engineered bioreactors. Sulfide produced in the sulfate reduction process was recycled to step 1 for metals precipitation. Selenite/selenate was partly removed in the sulfide precipitation step, whereas the excess was biologically reduced and removed as selenium to concentrations <0.2 mg/l.

Jan 1, 2003

By P. Shang

Fly ash and zeolite have strong absorption to cations since their porous microstructure. The porosities of fly ash and zeolite can also be increased by modification, which improves the absorption of the materials. This research showed that the effects of modified fly ash and zeolite to remove ammonia nitrogen from rainwater. The optimal reaction time, additive amount of materials, and pH value of the stormwater to remove ammonia nitrogen were experimentally determined. For modified fly ash, the optimal removal rate of ammonia nitrogen from 100 ml stormwater was 74.41% with the addition of 10.0g fly ash, 1.5 hours of the reaction time, and 8 of pH value. To the modified zeolite, the optimal removal rate of ammonia nitrogen was 51.22% at the reaction conditions of 2.0g of zeolite, 1 hour of reaction time, and 7 of pH value.

Jan 1, 2010