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By Thornton L. Neathery

Geologic investigation of a mineralized zone in eastern Alabama indicates that large quantities of talc and soapstone are scattered over a wide area close to the surface. Laboratory experiments show that this material may be upgraded to a high-quality talc. A market survey indicates that the talc deposits may be of current and long-range interest. The anthophyllite asbestos which is associated with the talc does not appear to occur in sufficient quantities to be considered as a primary commercial source.

Jan 1, 1967

By Ira Brotman

The Virginia Port Authority and the U.S. Army Corps of Engineers are partnering to construct the Craney Island Eastward Expansion (CIEE) to meet the dual purpose of extending the life of Craney Island as a dredged material management area and providing land for a state-of-the-art marine terminal. The over 500-acre (200-hectare) expansion provides additional upland dredged material capacity for the Hampton Roads Harbor by constructing perimeter dikes, that once filled, will provide land for the development of a container terminal. In the winter of 2010/2011 the first stage of sand fill was placed, followed by the installation of approximately 12 million linear feet (MLF) (3.6 million linear meters, MLM) of marine PVDs. With over 36 MLF (10.9 MLM) of PVD required to complete dike construction the project will be one of the largest PVD installation project in the U.S. his paper details the challenges associated with the construction of the cross dikes, in particular the design, testing, installation and monitoring of prefabricated vertical drains (PVDs) installed overwater to depths of over 130 feet (40 meters) for foundation improvement in the insitu very soft Norfolk Clay. With expected settlements of 20?30 ft (7-10 m) and 30 percent average strains, the discharge capacity of the PVDs was of particular concern. Laboratory data is presented showing the magnitudes and variability of discharge capacity under different confining pressures in both a straight and buckled condition. The method of installation and monitoring of the marine PVDs in open water included developing a specialized barge and sophisticated positioning and data collection system to verify installation location, depth of penetration and track quantities. An observational method, including material testing, detailed surveys, periodic in-situ testing, and instrumentation, was utilized by the project team to assess the project?s progress and allow for validation of consolidation and strength gain rates and magnitudes.

By H. L. TERWILLIGER

THOSE of us who have been following rock drilling work for the last 15 or 20 years can recall some of the problems that were encountered with the old piston type of rock drill and the solid steel which it used. There was frequent trouble in keeping a straight hole in badly broken ground when using the ordinary four- point bit that had a flare on the wings of about 14". The drill steel, when pounding down its hole, would follow the line of least resistance and draw away from the desired line when it encountered a weak side in the ground through which it was drilling. Some would overcome the difficulty by making long winged bits to prevent the steel crowding over; this would relieve the troubles to a great extent. There was trouble with the rifling of drill holes and inability to drill round holes in some ground. The cure for these ills was to use the "X" bit, rather than the crossbit. The "2" bits were brought out in an effort to make it easier to drill a round hole in bad ground. Most of these troubles were before the days when the mechanical drill sharpener was in as common use as it is today. It was not until the introduction of the Leyner type of rock drill, requiring hollow steel that the users of rock drills found themselves confronted with more difficult prob- lems than they had ever encountered before with drill steel because the steel had to stand more severe service.

Jan 1, 1924

By S-L. Weeber

Ash fusion temperature is the temperature at which the mineral matter in coal begins to soften, flow and fuse. It is an important parameter relating to coal utilization. Optimum ash fusion temperatures derived from coal in the Witbank Coalfield region are approximately 1400°C, and higher, although temperatures above1300°C may be deemed acceptable. This study attempted to determine which factors, mineralogical or inorganic-chemical, influence variations in the ash fusion temperatures in certain coals. Coal was sampled from the Number 2 coal seam at opencast and underground workings at New Clydesdale Colliery, Witbank Coalfield, South Africa. The samples represented known low and high ash fusion temperature coal. Analyses performed included proximate analyses, calorific value determination, percentage sulphur, ash fusion temperatures, ash analyses (composition of ash), X-ray diffraction, scanning electron microscopy and petrographic studies. Results show that although a complex relationship exists between ash fusion temperature and the various geological and coal parameters, some positive correlative results were obtained. These indicate a possible relationship between low ash fusion temperatures and i) finer size fractions, ii) an increase in iron content present in the form of pyrite and iii) the form in which pyrite is present, namely cleats. High ash fusion temperatures tend to correlate with i) the absence of pyrite or ii) pyrite present as framboids.

Jan 1, 2000

By Darren Medd

Kumtor Gold Company (KGC) currently operates the 500,000 tonnes per day Kumtor open pit gold mine located in the Issyk-Kul region of the Kyrgyz Republic at an elevation of more than 4,000 m. To supplement the open-pit mill feed with high grade underground ore from outside the current pit limits, KGC started pre-production design and development of the underground mine for the SB ore zone in late 2006. The initial phase of pre-production development consists of exploration and haulage declines which, upon completion, will provide ventilation and access to the underground mine. Design and construction of these declines presented many challenges to the project team considering the mines unique location at high altitude, the limited experience with Western underground mining techniques in the Kyrgyz Republic, and the impact of the nearby Davydov glacier and resultant ground conditions. Completion of the exploration and haulage declines was undertaken jointly by KGC and mine contractor, J.S. Redpath Limited (Redpath). The initial phase of development including several ground falls provided detailed information on geotechnical ground types and conditions that were useful in determining the overall mine design and methodology for production. This paper covers the various aspects of the design and construction process of developing the declines under the glacier, minimizing the likelihood of further ground falls, and the journey of both KGC and Redpath which led to the successful breakthrough between the declines on 01 July 2012.

Aug 1, 2013

The Winton Basin is one of three Southland sub-basins. The oldest known sediments are Early Oligocene terrestrial shales, sands and lignites deposited in half grabens formed as a result of oblique extension. A marine transgression in the Oligocene deposited mid-outer shelf to upper bathyal mudstones. Shallowing of the basin and tectonic quiessence lead to limestone deposition in the Early Miocene. Regional tilting led to uplift in the north and east and deposition of terrestrial lignites and gravels across the basin and the basement high to the south.

Jan 1, 1992

By Aline Lima da Silva

The present work is focused on the thermodynamic study of the methane or biogas mixtures conversion on Cu-ceria catalysts. Several experimental studies reported in literature have demonstrated the ability of these materials to operate as SOFC anodes for direct methane oxidation, with the evidence of enhanced tolerance towards sulfur poisoning and carbon deposition. More recently, experimental investigations have shown the feasibility of Cu-ceria anodes to directly operate with simulated biogas feeds at intermediate temperature (1023K). In this way, the effect of the ceria redox properties on the equilibrium composition is investigated, considering methane or biogas mixtures as the fuel. Conditions under which carbon deposition and sulfur poisoning can be prevented are determined. Our study combines results from the classical thermodynamics, obtained with the help of FactSage software, with the new Cu-S and Ni-S diagrams proposed in literature, which were calculated based on the Density Functional Theory (DFT). These diagrams are able to predict a region where sulfur interacts with the metal surface through chemisorption. A comparison between the performances of Ni-YSZ and Cu-CeO2 catalysts is established from a thermodynamic viewpoint. Theoretical results are in agreement with the experimental trends from literature.

Aug 8, 2018

Geophysical methods are useful non-invasive means of collecting subsurface information on the environmental impacts of resource developments. Techniques such as seismic refraction, ground probing radar and magnetics are well established tools for environmental studies of waste disposal sites. Repeat resistivity surveys, gravity surveys, and infrared or multispectral remote sensing hold great promise for monitoring environmental changes. Examples from New Zealand include geothermal field monitoring, which may involve the use of geophysics for .detecting changes of surface thermal activity, hydrothermal eruptions, induced earthquakes, contamination or depletion of shallow groundwater, and subsurface fluid recharge. Other examples include resistivity monitoring of contained effluent disposal ponds, tailings dams and landfills. Experience has shown that care is necessary to identify the natural variability of the parameter measured before drawing conclusions regarding an observed change.

Jan 1, 1994

By G J. Harbort, Z Pokra

It has been observed in several Jameson cell installations where the source for flotation feed is deslime screens, that the recovery of coal particles greater than 0.5 m is not as great as that of finer material. Consequently, a research project was undertaken at a CHPP in the Bowen Basin, Queensland, to assess the possibility of increasing the recovery of coarser particles (+0.5 mm) within the downcomer of the Jameson Cell. The effect of decreasing turbulence and agitation in a commercial-scale downcomer was investigated to assess the effect on the recovery of both coarse and fine coal particles. This paper details the findings of the testwork, summarising the results relating to differences in the operating parameters within the downcomer.

Jan 1, 2005

By K-H. Frohne

This report presents a study of the Cooper sand of the Fork Run pool of Warren and McKean Counties, Pa., and a prediction of the secondary oil recovery by gasflooding the reservoir. A computer program employing a modification of the Craig, Geffen, and Morse secondary recovery calculation was used to make the gas flood performance forecast and is presented in the appendix. The Cooper sand reservoir in the Fork Run pool lies at a depth of about 1,900 feet and covers an area 1/2 mile wide by 2-1/4 miles long. Original oil in place is estimated to have been 8,266,000 STB. The primary recovery mechanism is solution gas drive, and ultimate primary recovery may reach 20 percent over a well life of 90 years. Two computer predictions were made for gas flooding the Cooper reservoir. The first was for a 25-acre pilot five-spot utilizing existing wells, but project economics were poor since only 25 percent of injection gas is utilized for pilot oil recovery. Recovery was 71,000 STB, or 22 percent of oil in place at flood initiation, but required 25,700 scf gas injected per STB of oil recovered. In the second prediction, pilot area performance was projected for the entire Fork Run pool, and economics became good. Recovery was 1,753,000 STB from 25 five-spots after the injection of only 6,400 scf per STB of oil recovered.

Jan 1, 1969

By S. Rideout

As Assistant Director for Program Support for the Office of Surface Mining Reclamation and Enforcement (OSM), a bureau of the U.S. Department of the Interior, I am responsible for the regulatory and abandoned mine land programs under the Surface Mining Control and Reclamation Act of 1977, which governs the environmental impacts of coal mining. My perspective is influenced by my current position and my previous positions in government and private industry. Sustainability is a cooperative effort of many parties and can only be achieved if each assumes their responsibilities for making it happen. I will highlight some of my thoughts on the role of government in achieving sustainability in the mining arena.

Jan 1, 2007

By Edward (Ted) R. Lord

The application of thickened/paste tailings for surface disposal has been practiced for many years but has recently started to gain wider international acceptance. With tailings ponds coming under increasing environmental scrutiny, there is growing momentum towards mine/tailings plans that greatly reduce the size or even eliminate tailings ponds completely. This paper provides examples from the author's own experiences of the application of thickened/paste tailings for surface disposal in different countries, under different climatic conditions and in different industries. The paper will also comment on current research initiatives and future trends.

May 1, 2001

By V. A. Marple

At the Twin Cities "lining Research Center (TCMRC) a project is underway to determine how varying the parameters of a coal-cutting process would affect the amount and the size distribution of the generated dust. The cutting parameters being investigated are the cutting speed, depth of cut and shape of the cutting, tool. To accomplish this research ft is necessary to collect and transport the coal dust venerated at the cutting tool to measuring instruments for analysis. The purpose of this contract was to develop and deliver a system of instruments for measuring the size distributions of the generated coal dust. The instruments employed are essentially those developed for particulate air pollution measurements (1, 2). The instrument system covers a particle size range of 0.005 to 20 microns and is capable of performing in situ measurement and presenting data in real time.

Jan 1, 1974

By David Allen Jones

A depleted county gravel pit was rehabilitated by contracting an artist to convert it into sculpture, rather than using traditional reclamation methods. The sculptor's ideas were generally implemented as designed, but problems arose because of a faulty survey and severe weather. Public reaction was critical. A design symposium was presented by retaining six artists to prepare designs for varied sites. A public forum was offered and video-documented for broadcast. A new art-reclamation project grew out of this project.

Jan 1, 1981

By R. Karl Zipf, Suresh Bhatt

Highwall mining is an important coal mining method. It appears that upwards of 60 highwall miners are presently in operation, and they may account for approximately 4% of total U.S. coal production. A review of the Mines Safety and Health Administration (MSHA) data over the 20 year period from 1983 to 2002 identified 9 fatalities attributable to auger and highwall mining of which inadequate ground control accounted for 1/3. In the past 5 years, 1 fatality occurred in highwall mining. Estimates of the manpower requirements in highwall mining suggest that its fatality rate is essentially the same as for surface coal mining, thus highwall mining appears to be a very safe modern mining method. Highwall stability is the major ground control related safety concern, and operators are required to develop and follow an appropriate highwall mining ground control plan. The plans usually specify the following geotechnical parameters: hole width, maximum hole depth, maximum overburden depth, seam thickness, web pillar width, barrier pillar width and number of holes between barriers. Calculated web pillar stability factor exceeded 1.3 for most designs evaluated. This study examined records from 5,289 highwall miner holes with a total completed footage of about 2,560,000 feet to understand the reasons for early pull out. Average lost footage is typically about 20% of planned footage. Only 35% of the holes reached planned depth, and 20% were short due to rockfalls. Water and adverse geology accounted for 15% of the losses. Mechanical/electrical problems, guidance, and slope stability problems accounted for the remaining 30%. Web pillar stability factor for these holes also exceeded 1.3 in 95% of cases. Best practices to avoid trapped miners include: avoid mining in stream valleys, avoid mining near outside corners, careful alignment of each hole and the use of an onboard guidance system. Several issues in highwall mining ground control require further investigation including highwall mining through old auger workings, highwall mining near old underground mines, multiple-seam and multiple lift highwall mining and finally the size and frequency of barrier pillars.

By Keet B. A, Waid J. S

The Gippsland Basin is one of Australia's most important producers of petroleum products. An inevitable byproduct of the production, refinement and transport of the millions of barrels of oil is thousands of tonnes of waste. These wastes are generated from the wellhead through to the petrol bowser and range from oily brines and coal tars to oil and petrol contaminated soils. The vast majority of these wastes are of a relatively low toxicity and most importantly are carbon-based and biodegradable. Current disposal practices tend to ignore the latter characteristic and inappropriate and/or expensive waste disposal solutions such as landfilling (tipping), incineration or ocean outfalls are the result. A very cost effective and environmentally friendly alternative is land treatment of such wastes. Landfarming, as it is called, has been successfully practiced in Europe for over a decade. Essential features of the system are: ò Application of a predetermined quantity of biodegradable waste in liquid, sludge or highly contaminated soil form, to pre-ploughed soil with concurrent addition of nutrients (N, P and trace elements) and lime to encourage bacterial activity. ò Harmless bacteria already present within the soil break down the carbon-based compounds into carbon dioxide, water and waste heat, WHILE concurrently generating new cells. The breakdown occurs over a period of weeks to months and continues with time with the extremely low levels of the more difficult waste types being the last to disappear. ò Further waste is applied to the soil at regular intervals. The treatment area may be dedicated to landfarming or may be used alternatively for agricultural purposes. Application rates vary but may be as high as 800 tonnes per hectare per year for wastes such as refinery sludges.

Jan 1, 1992

By Hart G. H

In tectonically disturbed zones within coal seams, decreases in the amount of kaolinite in the cellular structure of inertiniterich coal are accompanied by increasing kaolinite contents in fractures within the coal and/or rocks of immediately overlying horizons. This is due to fracturing of the inertinite microstructure by tectonic disturbance and remobilization and redistribution of free, fine-grained material (kaolinite and/or inertodetrinite.) Ascending waters are believed to transport the kaolinite in suspension, and redeposit it in the fractures and pores in the overlying horizons. This removal of material from the inertinite-rich coal leads to an increase in porosity (higher free gas storage), a presumed reduction in coal strength and an apparent increased proneness to instantaneous outbursts of coal and gas.

Jan 1, 1983

By S. B. Robertson, D. R. Dolinar, G. E. Hinshaw, G. M. Molinda, D. M. Pappas

Rock falls in coal mines cause many injuries each year. Most of these injuries are not caused by major roof collapses, but from falls of smaller rocks from the immediate top or roof skin. Even though safety professionals and mine operators strive to reduce these types of injuries, there has not been a substantial decrease in the rock fall injury rate over the past decade. Various surface controls are used in mines to control the roof skin. One control that has proven to be very effective is roof screening. Roof screen effectively controls roof skin and provides a high roof surface coverage. Although many mines are reluctant to use screen for primary skin control because of the additional costs of time and materials, others are having great success at controlling both the costs and surface rock. In this study, injury data are presented that show a dramatic reduction in roof skin injuries when screening is used. Much of this success is due to the protection from falling rock that the operators receive from roof screen. Five case studies in which roof screen was used are presented along with the associated costs of materials, impact on bolting advance rates, and potential ergonomic risks. The effects of roof screening on skin control and safety are also included. Finally, this paper provides information about best practices and features of roof bolting machines that affect production and safety.

By Silvia Misk, Cristina Araújo, João Felipe Costa, Roberto Rolo

Linear estimation methods are widely used for resource evaluation. Among the existing linear estimation methods, ordinary Kriging (OK) was accepted as the best estimator to determine the average ore grade of each block. However, OK is inadequate for modeling small blocks in relation to data spacing, resulting in over-smoothed models. In this study, the results of the recoverable resource from the short-term model are compared to estimated models generated by the traditional method, i.e., OK, and non-linear methods. The conclusion is that non-linear methods improve the accuracy and precision of the long-term model when compared to the model generated by OK.

Jun 25, 2023

Nowadays, technology has improved to extract dimensional stone blocks at quarry sites and also to process these at processing plants for making slabs and tiles. In the process of quarrying and processing, performance evaluation of machinery is very important to achieve optimum output at minimum cost with improved technology. Cost analysis of improved technology includes parameters such as manpower, energy consumption, tool consumption, depreciation, maintenance and also others. The chainsaw machine with long boom and rail in marble quarries and multi-diamond wire saw machine for slab making from granite blocks at processing plants have recently been introduced in India. Thus, a study was carried out under a research project on these machines to assess their suitability. In this paper, performance evaluation and cost analysis of chainsaw and multi-diamond wire saw have been carried out with existing machines on the basis of research findings.

Dec 6, 2010