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By Gary D. Aho

The United States on a daily basis no consumes about 15MM barrels (2.38 x 106m3) of oil; 5MM (0.79 x 106 m3) of this is imported. This compares tai a daily consumption of 18MM (2.86 x 106 m3) in 1980 when we imported 8MM (1.27 x 106 m3). We are producing the 10MM barrels (1.59 x 106 m3 ) of conventional oil at home from what amounts to just 2% of our domestic energy reserves. Nearly 90% of our total domestic energy reserves occurs in solid forms such as coal, oil shale, and tar sands; this is more than enough to meet our needs for the next 100 years. Worldwide, oil shale is second only to coal as a potential source of energy and the U.S. has approximately one-half of the world oil shale reserves which average over 25 gallons per ton (10.43 x 10-2 L/kg). Since the United States has immense oil shale resources, including some of the richest in the world, and since oil shale produces a superior transportation fuel, it would seem logical that the U.S. would be prudently developing this domestic resource. Unfortunately, despite over 50 years of research and a number of false starts, there is not a commercial shale oil industry in place today. There are a number of recurring roadblocks which have hindered private industry's efforts to develop oil shale and we will look at some of these.

Jan 1, 1983

By R. R. Fernández

Newmont Mining Corporation has been processing refractory gold ores by roasting since January 1995. The ores are refractory due to the association of the gold with iron sulfides, namely pyrite and marcasite, and the presence of carbonaceous components and is oxidized in an oxygen-enriched gaseous atmosphere. The structural characteristics of the calcine have a strong influence on the eventual recovery of gold by cyanidation. These characteristics are strongly dependent upon the roasting conditions, mainly the roasting temperature. Originally, the sulfides and carbonaceous matter were oxidized at a temperature that typically ranged between 535 and 560 °C. Controlling the roasting temperature within the lower and narrower range of 510 to 515 °C produced a calcine with a larger surface area(e.g. higher porosity), which resulted in a gold recovery increase of3.3 percent in 2001 equivalent to 5.1 million dollars of additional gross revenue. The new strategies of operating at temperatures never tested before are discussed. It constituted a great challenge to the control room operators for the lower operating temperature falls much closer to the ignition temperature of the sulfide ore and smaller and more frequent adjustments in operating parameters were needed to improve and maintain high gold recoveries. Based on the encouraging results that were achieved in 2001, a decision was made to install a “smart” process control system because the roaster temperature control was performed by manual inputs from the control room operators. The development and implementation of the control system to reduce or eliminate the temperature variability between the different control room operators commenced in June of 2002 and was fully operational by the end of October. Lower roaster temperatures were achieved (500 to 505 °C), which resulted in further increase of gold recovery by about two percent. The overall recovery increase equated to 8.0 million dollars of additional revenue for the first 10 months of 2002.

Jan 1, 2003

By K. H. McDaniel

This paper describes the development of a Windows-based interactive mine ventilation simulation software program at the Waste Isolation Pilot Plant (WIPP). To enhance the operation of the underground ventilation system, Westinghouse Electric Corp. developed a program called WIPPVENT. While WIPPVENT includes most of the functions of the commercially available simulation program VNETPC from Mine Ventilation Services Inc. and uses the same subroutine to calculate airflow distributions, the user interface was completely rewritten as a Windows application with screen graphics. WIPPVENT is designed to interact with WIPP ventilation-monitoring systems through the sitewide central monitoring system. Data (e.g., air quantity and differential pressure) can be continuously collected from the underground ventilation remote-monitoring and control system and from the mine's weather stations (psychrometric data). Furthermore, WIPPVENT incorporates regulator characteristic curves specific to the site. The program utilizes this data to create and continuously update a real-time ventilation model. This paper discusses the design, the key features and the interactive capabilities of WIPPVENT.

Jan 1, 1997

By Thomas H. Ferrigno

Modern Plastics (July, 1983) reported that about 2.2 million tons of mineral fillers were expected to be consumed by the plastics industry that year, of which 7096 was limestone derived. The combination of fillers and polymers is called a composite and, in the more general sense includes continuous and discontinuous components in a matrix. The only significant technical advance in the fillers industry has been the greater general availability of surfied (Ferrigno 1959), an acronym for surface modified, fillers. The many reasons for this occurrence will be given in detail later, but the primary reason lie with differences between inorganic filler surfaces and the polymers which bind them together to form the composite. Minerals and glasses (fiberglass, fly-ash and beads) have surface tensions in excess of 200 dynes/cm, whereas organic materials have surface tensions less than 75 dynes cm. Water has a surface tension of 72 dynes/cm and is always present as an absorbed layer on high surface tension materials to reduce the surface tension. Although almost any organic liquid or polymer has a surface tension low enough to displace the water layer, the highly polar nature of filler surfaces requires highly polar agents to produce a permanent effect, and frequently the water is so tightly bonded or so much more active that the displacement is temporary. Furthermore; the water layer causes tiny particles to adhere to each other (agglomerate) to make sepaartion or dispersion of the individual particles very difficult. The solution to these problems is then to form a chemically bonded layer on the filler surface similar to that of the polymer so that immediate wetting, dispersion and uniform distribution of the filler particles is obtained.

Jan 1, 1985

By Harry H. Peek

Artesian pressures of unusual magnitude occur in the deeper aquifer units beneath a considerable part of southeastern North Carolina and extend into South Carolina. The high pressures were first observed in 1968 in wells near Wilmington that were drilled to "basement" rock and which were screened between depths of about 260 to 300 m (meters). The pressure was recognized by Peek and Heath1 as an anomalous geo-pressure and unrelated to recharge conditions in the region. Since 1973, much new information has been obtained on hydro-geologic conditions in the area and a preliminary report on the deep artesian pressures was published in 1975.2 Most of the basic information has been obtained from groundwater research stations constructed by the Groundwater Section of the North Carolina Department of Natural and Economic Resources as a part of Ground-water studies in the Coastal Plain Region. These stations consist of an exploratory well drilled to basement rock with wells completed in each principal aquifer unit to provide data on aquifer characterestics, water levels and water quality.

Jan 1, 1977

By N. Langsford

The Archaean Yilgam craton has been a major gold province since 1888 with production and reserves of about 4700 tonnes. Production in 1994 was about 135 tonnes. The largest deposit, the famous Kalgoorlie Golden Mile, contains about 2000 tonnes of gold. About 40 deposits containing more than 35 tonnes (1Moz) of gold has been discovered so far in the Yilgarn. Most of the craton has deep weathering profiles inherited from previous tropical climatic conditions, modified by subsequent arid conditions. A mantle of transported material covers much of the variably stripped weathering profiles. Resolving the geology of the volcanic-sedimentary units (greenstones) and the structures that host the gold mineralization relies heavily on aeromagnetics and shallow drilling.

Jan 1, 1995

By R. J. Sheets

In 2009 the Gold Quarry open pit mine, located 11 km northwest of Carlin, Nevada, USA, experienced multiple large-scale slope instabilities of the upper east highwall that reduced gold ore extraction for nearly 18 months. The slope instabilities occurred within a weak, consolidated sedimentary sequence that exhibits strength characteristics that are transitional between soil and rock. Instability initiated as mining exposed the lower clay-rich sub-units of the Carlin Formation (Fm.). This deformation created preferential flow paths that allowed groundwater from the upper sandy sub-units to infiltrate low permeability clay-rich sub-units, thereby enhancing deformation of the slope toe which in turn destabilized the upper portion of the highwall. The outcome was a 160 m high slope instability that had a lateral run-out of 850 m. The effort to return the pit to ore production required both the geotechnical and hydrogeological investigations and the preliminary remediation mining activity to be concurrent. This approach required the development of detailed safety procedures and a requirement to modify the remediation design as new results were obtained. An initial challenge was to mitigate a near vertical, 90 m headscarp with blast induced, localized slope failures. Back-analyses applying numerical modeling indicated that the failure surface did not coincide with initial interpretations based on field observations; drilling results eventually confirmed this alternative failure geometry. The final remediation design incorporated shallower slope geometries and an approximately 3 Mt buttress along the base of the Carlin Formation and bedrock contact to reinforce the lower clay-rich sub-units. The outcome is a stable highwall within the Carlin Fm. following nearly ten years of repeated slope instability, and an example of the necessity to conduct appropriate geotechnical and hydrogeological studies during the early stages of a new layback evaluation or new open pit development.

Feb 23, 2014

By L. Bernoth, I. Firth, S. Rhodes, P. McAllister

As biotechnologies emerge from laboratories into main-stream application, the benefits they offer are judged against competing technologies and business criteria. Bioremediation technologies have passed this test and are now widely used for the remediation of contaminated soils and groundwaters. Bioremediation includes several distinct techniques that are used for the treatment of excavated soil and includes other techniques that are used for in situ applications. They play an important and growing role in the mining industry, for cost-effective waste management and site remediation. Most applications have been for petroleum contaminants, but advances continue to be made in the treatment of more difficult organic and inorganic species. This paper discusses the role of biotechnologies in remediation and pollution control from a mining-industry perspective. Several case studies are presented, including the land application of oily wastewater from maintenance workshops, the composting of hydrocarbon-contaminated soils and sludges, the bioventing of hydrocarbon solvents, the intrinsic bioremediation of diesel hydrocarbons, the biotreatment of cyanide in water from a gold mine, and the removal of manganese from acidic mine drainage.

Jan 1, 2000

By J. J. Harrington

The pH control system at Kennecott Copper Corporation's Nevada Mines Division concentrator consists of two independent systems, lime dilution and lime addition. Lime dilution is accomplished in a mixing tank where slaked lime and water are introduced proportionately. The desired dilution of the milk of lime is determined by the electrical inputs provided by eight pH probes, one per grinding section. The inputs are averaged and applied to a time base generator. The summation output of the time base generator determines the proportion of lime and water that are to be mixed and applies this input to a voltage sensitive switching device. The switching device provides a signal to one of two relays which will add either slaked lime or water, dependent upon the summation output. The entire cycle is based on a two-minute repetition rate to allow for sufficient mix time. Responsivity is controlled by maintaining a limited maxi- mum solution level in the mix tank. Lime addition is controlled independently within each grinding section. The electrical input from the pH probe in a given section controls the solenoid valves which provide lime to each of the ball mills. The valves remain open within a time range capable of maintaining the pH of flotation feed at a given set point.

Jan 1, 1975

By W. R. Reed, J. P. Rider

"The National Institute for Occupational Safety and Health (NIOSH) Office of Mine Safety and Health Research (OMSHR) has recently developed a series of models utilizing computational fluid dynamics (CFD) to study airflows and respirable dust distribution associated with a medium-sized surface blasthole drill shroud with a dry dust collector system. CFD models were constructed in ANSYS FLUENT Version 15. Previously run experiments conducted in the NIOSH full-scale drill shroud laboratory were utilized to validate the models. The setup values in CFD models were calculated using experimental data obtained from the drill shroud laboratory and measurements of test material particle size. Subsequent simulation results were compared with the experimental data for test scenarios, including 0.14 m3/s (300 cfm) bailing airflow with 2:1, 3:1, and 4:1 dust collector-to-bailing airflow ratios and 0.24 m3/s (500 cfm) bailing airflow cases with 2:1, 3:1 and 4:1 dust collector-to-bailing airflow ratios. For the 2:1 and 3:1 ratios, results showed the calculated dust concentrations from the CFD models were within the 95% confidence intervals of the lab experimental dust concentrations. This paper describes the methodology used to develop the CFD models, to calculate the model dust input, and to validate the models based on experimental data. Problem regions were identified and revealed by the simulation of a dry dust collector system. The simulation results could be used for future development of dust control methods for a surface mine blasthole drill shroud. INTRODUCTION In surface mines, production drilling is an essential process in blasting which fractures the hard rock overburden for removal. Holes with a predetermined pattern, diameter, and depth are drilled into the overburden to introduce explosives. During the drilling process, considerable amounts of respirable dust are produced. Past research conducting area sampling at blasthole drills has documented time-weighted average respirable dust concentrations ranging from 8.68 to 95.15 mg/m3 [1] and 1.04 to 52.30 mg/m3 [2]. These high dust concentrations, which may contain silica, can lead to respirable dust over-exposures for the drill operator, drill helper, and other personnel in the vicinity. These over-exposures can lead to silicosis, an occupational lung disease that has no cure and is ultimately fatal. In order to prevent the development of silicosis to mine workers, the Mine Safety and Health Administration (MSHA) regulates the exposure to respirable dust. For metal/nonmetal (M/NM) mines, MSHA has adopted the threshold limit values recommended in 1973 by the American Conference of Governmental Industrial Hygienists (ACGIH) [3]. The total airborne dust standard is 10 mg/m3. However, if the sample contains greater than 1 percent quartz (the most common form of crystalline silica), a respirable dust standard is calculated with the following equation: Respirable dust standard = (10 mg/m3) / (% respirable quartz + 2)"

Jan 1, 2016

Traction of mining vehicles is well understood for a variety of unfrozen road surfaces, allowing optimal design of mine access and haulage roads. However, no such characterizations exist for the frozen or partially frozen surfaces typically encountered in Northern regions. Recent work by U. S. Army researchers suggests methods for characterizing roadway traction for any vehicle on the basis of test measurements made with a standard test vehicle. Such a test vehicle was designed, and several sets of test data were recorded at the onset of winter in Fairbanks, Alaska. This work suggests methods for future research and possibilities for the use of such research in designing drive systems, tires, and mine roads for Arctic and sub-Arctic mines.

Jan 1, 1995

By P. M. Krishna

A five-year effort by the ASTM subcommittee E10.14 on Uranium Resource Evaluation has culminated in the approval of E901-82, Classification System for Uranium Resources. The standard classification was prepared with participation of representatives from the Dept. of Energy, the Dept. of Interior's Geological Survey and Bureau of Mines, utilities, and consultants. The classification of a resource is based on level of knowledge and the economic producibility of the resource at a given time. Alpha-numeric identifiers are used rather than words to avoid confusion with existing terms, definitions, and classifications. An effort is underway to develop estimation criteria to guide users in classifying a resource according to the above format.

Jan 1, 1983

By J. A. Oraniscak

Longwall mining operations continue to increase extraction rates and the potential to generate higher amounts of airborne respirable dust (ARD). The National Institute for Occupational Safety and Health (NIOSH) has gathered data from underground longwall surveys and laboratory crushing tests to identify the important factors influencing the amount of ARD levels generated. Coal-seam characteristics, operational parameters (i.e.,cut sequence, mining height, etc.), extraction rates and dust-control parameters (i.e., airflow, water flow, etc.) were examined to determine their influence on ARD levels measured at longwalls during actual mining operations. ARD generated by a laboratory crusher while crushing bituminous coal samples collected from underground longwalls was also examined to determine if there were cor relations with coal-seam properties. Results from the longwall and laboratory data collected indicated that low-ash, high-volatile coals (low moist fuel ratio or MFR coals) generate higher amounts of ARD. It was found that face ventilation and water application to the coal product are essential elements to controlling longwall ARD levels.

Jan 1, 2000

By R. Pixler

Arch Mineral Corporation and Rocky Mountain Energy's Medicine Bow Mine in Wyoming presented an interesting challenge to the concept of mining a multiple-seam, dipping coal in the Hanna Basin. The 3362 and 2962 pits at MBCC were designed in a multiple seam coal consisting of 4 (and in some areas 5) bands of coal; these coal beds are all in the Ferris formation. The area was subject to some localized faulting and a major fault caused a physical restraint that we mined up against in our final cut. Using a 1570 dragline as the principal stripping machine, the concept of developing a bench for stripping the lower seams from the low-wall side of the pit was initiated. The results of this method of stripping were very satisfying for this pit through the completion of pit life and prompted us to use it in other areas at MBCC and at our other operations. Mining a dipping coal presents a small twist to conventional "flat" coal stripping. The spoil has a tendency to continually try to slide into the pit and the increased overburden on each cut as you mine down the dip creates spoil problems unless adequate design provisions are made prior to stripping.

Jan 1, 1986

By A. Iannacchione

Most legacy drift mines entered the coal reserve from outcrop and developed up-dip. The Surface Mining Control and Reclamation Act of 1977 changed this way of mining, requiring all new mines with acid- or iron-producing coal seams to be designed so as to prevent gravity water discharges from the mine. This Act requires engineered barriers to contain the mine pool. In many cases, mine layout designs focus primarily on the size and hydraulic performance of the un-mined coal barrier between the up-dip mine pool and areas where down-dip surface discharge is possible. In other cases, designs focus on preventing discharges from barriers contained within the strata surrounding the mined coalbed. This paper focuses on a detailed analysis of the factors responsible for preventing mine pool discharges to surface waters. Important factors include: mine layouts, mining methods, hydraulic head and conductivity, and geology. While the exact causes for the successes and failures could not always be determined, reasonable mechanisms are presented.

Feb 23, 2014

The 6th International Mine Ventilation Congress (IMVC) was held May 17-22,1997, in Pittsburgh, PA. This marked the second time that the IMVC was held in the United States. The first congress, organized in 1975 by the Mine Ventilation Society of South Africa, was held in Johannesburg. Since then, the meetings have been held every four or five years, with the 1979 meeting being held in Reno, NV. This was followed by Harrogot, England, in 1984; Brisbane, Australia, in 1988; and Johannesburg, South Africa, again in 1992. The IMVC provides an international forum in the field of mine ventilation for the purpose of sharing technology and experience. The meetings are attended by ventilation engineers, academics, consultants, government employees and vendors interested in mine ventilation. As was evident from this meeting, significant progress has been made in the field of mine ventilation. However, disasters continue to occur around the world and long-term health problems continue to affect workers. So there is a need for further improvements in ventilation technology. The highlight of the conference was the technical sessions in which more than 80 papers were presented by authors from more than 20 countries. In addition to the technical sessions, the conference featured field trips to a number of mine properties throughout the United States. Five short courses were offered on topics ranging from respirable-dust control to mine fires and explosions. The conference also featured a trade show. It exhibited the latest advances in ventilation equipment, computer application software, consulting and engineering services, and health and safety equipment.

Jan 1, 1997

By V. Rajaram

The Parachute Creek Member of the Green River Formation in the Piceance Basin, Colorado, contains vast reserves of oil shale, nahcolite, dawsonite, and other accessory minerals. The dry alkali process of sulfur dioxide removal using nahcolite (naturally occurring sodium bicarbonate) has great potential. A room and pillar mining scheme has been designed to extract a nahcolite zone occurring at a depth of 472 m, from the lease application area of the Yankee Gulch Joint Venture. Geotechnical parameters affecting mine design will be discussed. A preliminary development plan for mining at the rate of 1000 t/d will be described in detail.

Jan 1, 1977

By D. C. McDonald, P. R. Whincup, H. Duke

Due to grade, overburden depth and stability and the presence of groundwater it was considered impractical to recover gold contained in unconsolidated palaeochannel sediments by conventional mining, dredging or borehole mining techniques. A series of field experiments was conducted to determine the feasibility of recovery of gold by in situ leaching from sediments located at a depth of about 80 metres. The test wellfield site and plant are described together with field test procedures, results and wellfield rehabilitation procedures. Choice of sodium cyanide as leachant and laboratory testing are discussed in relation to groundwater and sediment chemistry and problems encountered in field tests.

Jan 1, 1989

By Werner Wenzel

Whisker growth during the reduction of iron ores The phenomenon of whisker growth can be observed in a number of solid-state crystallisation reactions, which, apparently, appear in6 the first instance as though they are two independent processes. From such reactions, one can find the whisker type of crystallisation on solid bodies. These examples show, that the whisker growth is neither due to certain crystal forms with predetermined temperature and pressureranges, nor to parameters, which, ad hoc, are necessary for the crystallisation. In all cases the whisker formation seems to depend on nucleation and the availability of crystallizing material in direct environment of such a nucleus, under given parameters of a system. One can generally state, that the research of whisker growth with the aim of establishing proper physical laws, to determine the foundamentals of whisker formation and whisker growth, is at present under active study. We can conclude that, although a great number of hypothesis have been proposed; no concluding theory has yet been arrived at. In the institute for ferrous metallurgy of the technical university of Aachen, research works are undertaken to find an explination to various metallurgical phenomena through help of whisker growth which was observed under varying conditions of iron ore reduction. This was possible by using refined microscopic techniques through which the whisker growth on solid oxyde substrates is detected. This refined technique combines the latest methods of surface examination with the help of stereo-scan-electron-microscope and proper and carefull preparation of surface to be stereo-scanned.

Jan 1, 1971

By G. W. McCaa

Plans for a large industrial development in the Upper Ohio Valley between Moundsville and New Martinsville, West Virginia, were announced in the Fall of 1955. This development consisted of a large aluminum plant to be .built by Olin-Mathieson; a 675,000 KW power plant to be constructed by the American Electric Power Service; and a large coal mine adjacent to the power plant to be developed by the Hanna Coal Company Division of Consolidation Coal Company. The Ireland Mine was designed to efficiently supply fuel for the power plant, and this was the first consideration in the location of facilities, design, and development of plant and the selection of the equipment. The first problem was to find a suitable area for the surface facilities. A level bottom area south of the power plant was reserved for future industrial plants and this area was also blocked off from the coal reserves by an old abandoned and flooded mine. The coal storage facilities of the power plant were on the north side of the plant and it was decided to locate the coal mine preparation plant on-the shoulder of a hill above the power plant. This location required the excavation of 70,000 yards of rock but permitted the driving of a belt slope from the plant at an angle so that the haulage roads underground would miss the abandoned Cresap Mine. This location also permitted the plant to be located at an elevation so that the conveyors leaving the plant were horizontal and had sufficient clearance above the highway and railroad tracks. The other surface facilities consisting of air shafts, supply slope, supply yard, office, bathhouse, shop and warehouse were located in the valley some distance north of the preparation plant. This location placed these facilities one mile nearer to the working area. Plans for design and development of the mine were started in November 1955; grading and clearing of surface area was started in January 1956; the air shafts and slopes were started in the Spring and Summer of 1956; and the first coal was produced from the supply slope in October 1956. The preparation plant was put in operation in March 1958, and by July 1959 was producing 8,000 tons per day.

Jan 1, 1959