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By Serge Ouellet

Identification and quantification of cementitious phases in cemented paste backfill (CPB) is difficult due to the fineness of tailings and the low binder content used in the mixture. Techniques such as X-ray diffraction and thermogravimetry were ineffective (mainly due to tailing mineral interference) to identify and quantify hydration products in most works reported in the literature. On the other hand, scanning electron microscopy (SEM) was used in many cases but mainly for qualitative purposes. This paper presents the development of a new approach based on a computer program (SEM-XMAP) that combines X-ray dot mapping images acquired by SEM and generates a coloured image representing the mineralogy and the microstructure of a given CPB specimen. The technique is applied to one CPB sample mixed with blast furnace slag (BFS) and acidic sulphated mixing water sampled in a mine dewatering system. The technique allowed identifying calcic matrix, unhydrated and partially hydrated BFS particles, and sulphated phases.

May 1, 2007

By Alfred Wild

The Kraftile Co. plant, Fremont, Alameda County, Calif.--the largest producer of glazed, structural wall units west of the Rocky Mountains--maintains modern processing facilities to evaluate and blend a wide variety of clays from several sources to produce quality products. The report desribes the prospecting, exploration, and test methods used to locate raw material sources and covers processing methods, cost factors, and trends. Also, the geologic and ceramic factors are considered in a general discussion of the economics, potentials, and requirements of clays as raw materials for ceramic tile manufacturing.

Jan 1, 1963

By Paul C. Schmall, John F. Donohoe, Arthur B. Corwin, Derek Maishman

Ground freezing was utilized to provide complete stability of the excavation face and complete groundwater cut-off for the jacking of the three tunnel boxes for the Interstate 90 / Interstate 93 approach to the Fort Point Channel crossing. Through a wide range of geological conditions and large buried obstructions, the freezing provided complete stability of the face so that a 11.5 m (38 ft) high free standing vertical face could be mined without the need for any additional face support. Obstructions were incorporated into the massive frozen ground matrix, and held in place so that they could be excavated with a minimum of disturbance. The freezing provided an absolute groundwater cut-off, and permitted the work to be done without disturbance to the active rail system immediately above. With the use of instrumentation such as borehole thermocouples, the effectiveness of the freezing was guaranteed and the jacking proceeded with complete confidence and assurance of the ground conditions ahead.

Jan 1, 2001

Gold was determined directly in eight different mill cyanide solutions, by atomic absorption spectroscopy in an acetylene-air flame. Some of the mill solutions were diluted with water to bring them into the most sensitive absorption region (5-50 p.p.m. Au) whereas those solutions with very low gold content «2 p.p.m.) were concentrated by evaporation.Calcium was complexed with ethylene diamine tetra-acetic acid (EDTA) to avoid the undesirable effect of a precipitate on atomization.When added to standard gold solutions, EDTA had no effect on absorption, nor did any of the impurities common in mill cyanide solutions.Known amounts of gold, ranging from 2 to 30 p.p.m., were added to mill solution'aliquots and recovered to within 100 ± 2·5 per cent. For duplicate determinations under normal worKing conditions, standard deviation was 1·32 p.p.m.Excellent agreement was found between atomic absorption gold values and accurate fire assay values.INTRODUCTIONAtomic absorption spectroscopy has been shown to offer a rapid and accurate method for the determination of trace amounts of a number of metal ions. In the field of primary metallurgy atomic adsorption has been used for routine determinations of lead, copper, silver, zinc, cadmium and iron in a variety of raw materials and intermediate products.The scope of atomic absorption spectroscopy was reviewed recently by Willis (1963).The noble metals silver, gold, platinum, rhodium and palladium were determined by atomic absorption from chloride solutions by Lockyer ·and Hames (1959). In their determination of gold down to 1 p.p.m., they found no interference from the noble metals, nor from considerable excess...

Jan 1, 1964

By B. Arjang

ABSTRACT: Ground stresses are one of the significant factors in the context of rockbursts and underground instability at some hard rock mines in Canada. Overcoring strain relief measurements using triaxiaI strain eel is were performed at depths between 60 to 1890 m at several mine sites to provide stress data for stability analysis and optimum mine design. Pre-mining ground stress determinations from 64 stress tensor analyses resulted in the following average stress gradients: Maximum horizontal stress. -Hmax - 8.18 - 0.0122 MPa/m depth Minimum horizontal stress. _-,,min - 3.64 - 0.0276 MPa/m depth Average horizontal stress. -11, 5.91 - 0.03-19 MPs m depth Vertical stress. '-, - 0.0266 - 0.008 MPa/m depth The maximum and minimum horizontal compressive stresses. with an average ratio of 1.75 ,0..45. prevail in east--west and northerly directions. respectively. Horizontal compressive stresses in excess of vertical overburden load were determined. indicating large variations in ratios to a depth of about 1000 m with decreasing trend towards depth. From present data. a particular regional zoning for the magnitude and direction of horizontal stress fields cannot be outlined. A common feature at mines with near vertical orebodies is that the maximum horizontal compressive stress acts perpendicular to strike while the minimum horizontal compressive stress is aligned on-strike. The vertical stress components approach the gravitational overburden load.

Jan 1, 1989

Study on Iron Ore Sintering with High Proportion of Specularite Concentrates Specularite iron ores have poor hydrophilicity and ballability as well as bad high-temperature reactivity, which restricts the large-scale application in the sinter and pellet production. In order to make the best use of the specularite concentrates, a novel process of Composite Agglomeration Process (CAP) is applied in this research. By the CAP, the percentage of specularite concentrates in the sinter mixture is increased to no less than 40 per cent as well as the coke breeze dosage is reduced by 0.3 per cent~0.6 per cent. Moreover, all the sintering indexes are obviously improved compared with the traditional sintering process. Researches on the metallurgical performances shows the finished composite agglomerates are high-quality burdens for blast furnaces. This investigation can provide an effective route to utilize the inferior specularite concentrates in the sintering.

Sep 13, 2010

By M. A. Leosson, S. H. Bottrell, R. J. Newton

Sylvite at Boulby is mined 1 140 m beneath the sea and the mine suffers from the influx of water. This is of two kinds: persistent flows originating in the Sherwood Sandstone aquifer and entering the evaporite sequence through fractures in the intervening mudstone, and impersistent flows which are transient in nature and of uncertain origin. Water from the overlying sandstone has become enriched with NaCl and large amounts of KCl and some Mg and Br have been added by interaction with the evaporites. Waters from the transient flows are isotopically distinct from those in the Sherwood Sandstone, being enriched in H and O. They are also saturated with respect to halite and sylvite, but have higher K/Na than the persistent flows and are much more enriched in Mg and Br

Jun 18, 1905

By T. R. Roy

"This paper presents an objective model for the estimation of fire risk potential of an underground coal mine panel by the bord-and-pillar method of mining where extraction is carried out by depillaring with caving. The fire risk rating procedure for the estimation of fire risk potential involved in the panel is described in detail. The model developed thereof is tested with the field data collected from different collieries across the country along with the laboratory data for critical assessment of fitness of the model. Some results showing the validity of the model are also cited here. Introduction The occurrence of fire in underground coal mine panels is quite common in India and elsewhere. These fires cause extensive loss of resources.Although substantial work has already been done by different research organizations, the problem has not been fully eliminated.The causes of panel fires depend not only on the spontaneous heating susceptibility of coal, but also on the extraneous conditions created in the panel due to the mining operations. From the studies done so far by various organizations, it is apparent that two types of parameters associated with spontaneous heating of a coal mine panel exist: intrinsic and extrinsic. Parameters related to the nature of coal, i.e., its physicochemical characteristics, petrographic distribution and mineral make-up are intrinsic, while the extrinsic parameters are related to the atmospheric, geological and mining conditions such as scope of leakage of air into the panel, wetness of mines, heat dissipation capacity of the panel, gassiness of seam, geological disturbances, method of extraction, size of panel, etc.Banerjee (1982) identified twenty-two mine parameters such as spontaneous heating susceptibility of coal, method of mining, geological disturbances, quality of overburden, degree of consolidation of coal mass, scope of accumulation of coal fines, etc. that can influence spontaneous heating in underground mines. He used the terms “high” and “low” for fire risk rating of each of these parameters. Since this approach is oversimplified, it can not determine the exact fire risk potential of an underground working."

Jan 1, 2003

By Sidney Katell

This report, covering the period January 1968 through December 1968, is a continuation of a series that began with the publication of Information Circular 7516 in October 1949. It is the tenth in a series of reports prepared in cooperation with the American Association of Cost Engineers. The abstracted articles are concerned with all phases of cost of engineering in the field of chemical and petroleum plants and related subjects. They are from the following sources: 1. American Association of Cost Engineers Bulletin. 2. Bureau of Lines Information Circulars. 3. Bureau of Mines Reports of Investigations. 4. Chemical Engineering. 5. Chemical Engineering Progress s 6. Chemical Week. 7. Coal Age. 8. Coal Mining and Processing. 9. Cost Engineering. 10. European Chemical News. 3 11. Hydrocarbon Processing. 12. Industrial and Engineering Chemistry 13. Oil and Gas Journal. 14. Petroleum Engineer. 15. World Oil.

Jan 1, 1969

By Bob Turnbull

The International Society of Explosives Engineers (ISEE), at its 1995 annual conference, established a Seismograph Standards Working Group to develop performance standards for blast vibration seismographs. This group was transformed into the Blast Vibration and Seismograph Section in 1997 with 5 working committees one of which was the Seismograph Standards Committee. Standards are essential to ensure that vibration records from different seismographs would report the same vibration levels within a stated tolerance. In 2000, the ISEE through the work of the Blast Vibration and Seismograph Section published the “Performance Specifications for Blasting Seismographs.” This document is available on the ISEE web site at www.isee.org/sections/blast.htm.

Jan 1, 2007

By T. Warren, R. Pender

"Significant strides have been made during the past decade to integrate the traditionally separate administrative functions of financial management, materials management and maintenance management.In 1983, Key Lake Mining Corporation (KLMC) brought on-stream one of the most technologically advanced mining operations in North America. There was a requirement to support this new facility with state-of-the-art management information systems.This paper will discuss the development and evolution of the corporation's computerized information systems with specific emphasis on the utilization of computer systems to assist maintenance personnel in performing their work activities:Note: In August of 1989, the administration and operation of the Key Lake Mine was assumed by CAMECO - A Canadian Mining and Energy Corporation.IntroductionThe Key Lake Mining Corporation was incorporated in 1979 and operates a $500 million uranium mining and milling complex located in northern Saskatchewan.The feasibility study and environmental impact statements for the Key Lake Mine were submitted in 1979and in August of 1981, following a public inquiry, approval to proceed with construction was granted. Ore processing commenced in October of 1983 and during 1984 a total of 10.4 million pounds of uranium oxide (U3O8) was produced. In 1987, an annual production of 13.5 million pounds was achieved clearly establishing Key Lake Mining Corporation as the world's leading producer of uranium oxide. Current ore resources are expected to extend production of the Key Lake facility into the year 2000."

Jan 1, 1990

By Berny F. Rivera-Vasquez

La enargita es un mineral refractario que genera penalidades en la venta de concentrados, problemas ambientales y manipuleo durante los procesos de fundición. En ese sentido, el presente texto señala que la lixiviación de enargita es posible en un medio de sulfato ácido a presión atmosférica y temperaturas moderadas. Esta nueva alternativa de lixiviación abre nuevos horizontes, ya que este proceso es el único proceso de lixiviación química en medio sulfato capaz de disolver eficientemente concentrados de cobre con apreciables contenidos de arsénico.

Sep 14, 2009

By P. -É. Boileau, VibRG, S. Grenier, M. Smets, T. Eger, J. Stevenson

Load-haul dump vehicles (LHDs) are used to move waste rock and ore in underground mining operations. The LHD is designed for bi-directional operation and the driver sits sideways to the direction of travel. LHD operators have higher reports of low back pain and neck discomfort than other mobile equipment operators who do not sit sideways in the vehicle, but are exposed to whole-body vibration (WBV)1. Exposure to WBV is linked with reports of lower-back pain, neck problems and spinal degeneration2,3. Static sitting postures, sitting with the neck and back twisted, and sitting with the back in an unsupported posture are also linked with an increased risk of developing back pain4. The objective of this study was to determine typical vibration exposure levels and driving postures for LHD operators. Methods Whole-body vibration exposure was measured at the seat-pan, in accordance with the ISO 2631-1 standard5, on seven LHD vehicles with a 10 yard bucket haulage capacity. Vibration data were recorded with a Biometrics™ DataLog II (P3X8) and stored on a 128 Mb Simpletech™ multimedia card. Comparisons were made to the ISO 2631-1 Health Guidance Caution Zone (HGCZ) in order to determine potential injury risk. Operator posture was monitored with three digital video cameras which were secured inside each operator’s cab to the top left corner, top right corner and back right corner. Reflective tape was placed on each driver’s shoulders, head, and back in several locations and in several locations on the vehicle seat in order to aid in posture coding. Posture coding was performed with 3DMatch v4.50 multiple video view analysis feature. Vibration measurement and posture recording occurred simultaneously for 60 minutes while the LHD operator performed typical duties. Results and Discussion Results indicate LHD operators may be exposed to whole-body vibration levels putting them at risk for injury (Table 1). According to ISO 2631-1 the frequency weighted acceleration values corresponding to the lower and upper limits of the HGCZ (for an 8 hr exposure duration) are 0.45 and 0.90 m/s2 respectively5. Six of the seven vehicles showed exposure levels within the HGCZ defined for 8 hours. Preliminary video analysis indicated LHD operators were exposed to potentially harmful levels of WBV while adopting asymmetric postures (Table 2). For example, one LHD operator (Figure 1) worked with his neck twisted greater than 40 degrees for 93 % of a 60 minute work cycle. According to the Swedish National Work Injury Criteria, neck rotation should be less than 15 degrees if the motion is required for greater than 80% of the work time6. Results of this study highlight the need to further examine the contribution of non-neutral working postures and

Jan 6, 2006

By Andre Zingano

The variation in pillar behavior at underground coal mines working in the Bonito coal seam is observed in both research and mining company case studies. There is no consistency in pillar behavior, as it varies from mine to mine. In some cases, it is possible to find rib yields for both excavation modes and pillar sizes. This paper?s objective is to investigate pillar behavior for different load conditions and pillar sizes. Three-dimensional numerical simulation models considering these factors were built. A matrix was then assembled to compare pillar behavior between loading conditions, as well as between different pillar sizes with the same loading condition. The results showed some pillar rib plasticity due to vertical loading and stress relief independent of the pillar size and load. For the same load conditions, the yielding thickness is the same for different pillar sizes.

Jan 1, 2012

By S. J. Schatzel, W. P. Diamond, F. Garcia

Methane explosions have historically been one of the major causes of fatalities and injuries in underground coal mining operations. Advanced numerical models and predictive modeling approaches have the potential to offer optimized methane control solutions for general mine planning purposes and to address specific methane-related operational problems. This paper describes the development of reservoir models for the longwall mining environment and their application for investigating the influence of various completion design parameters on the methane drainage effectiveness of gob gas ventholes. The influence of increasing longwall panel width on the effectiveness of current gob gas venthole completion and placement strategies in the Pittsburgh Coalbed were evaluated and optimized designs developed to capture the expected increase in methane emissions on the larger panel.

By David A. Lipton

In 1983, U.S. Bureau of Mines personnel examined mines, prospects, and mineralized areas to determine the mineral resources in the Carrizo Gorge Wilderness Study Area (WSA). The 14,571-acre WSA, located 42 miles east of El Centro, CA, is underlain primarily by Mesozoic granitic rocks and pre-Cretaceous metasedimentary rocks. Six prospects were found within the WSA and two mines are adjacent to it. Mineral deposits within the WSA have had insufficient development and rock exposures for calculating resources. The WSA contains no identified mineral resources; however, further exploration may disclose gem quality minerals. Two mines adjacent to the WSA, the Pack Rat and Beebe Hole, have produced gem quality kunzite and aquamarine from pegmatite dikes. According to the owners, a significant amount of gem minerals have been mined here in the last decade. Based on past production and the characteristic minerals indicating gem-bearing pockets, additional pockets are likely. Similar pegmatite dikes occur from Mt. Tule to Carrizo Gorge and may contain gem-bearing pockets. Pegmatite dikes also occur in the WSA near Rockhouse Canyon, but contained few of the mineral associations indicative of gem-bearing pockets. Manganese occurrences north of the Beebe Hole and Packrat Mines and within the WSA contain low concentrations of manganese. Significant sand and gravel were not identified. There is no evidence of deposits of oil and gas, or geothermal energy.

Jan 1, 1985

By Shosei Ph. D Serata

The Stress Control Method of mine design provides enhanced engineering control over the behavior of underground structures in comparison to conventional mine design methods. The same Method can be applied to achieve design control of surface subsidence. The basic mechanism relating undergroued deformation and surface subsidence is disclosed by mine simulations, using the REM (Rheological Element Method) computer code, whose predictions have been validated by field measurements. The key components of the underlying mechanism of surface subsidence have been shown to be the stress envelopes formed in the process of underground excavation. It has also been demonstrated that significant control of surface subsidence can be achieved by designing the geometry and timing of underground excavation to regulate the formation of stress envelopes. A field example is given in this paper to illustrate this application of the Stress Control Method.

Jan 1, 1986

By John C. Machisak

THIS PUBLICATION presents injury experience and employment data for the nonmetal mining industry in the United States for 1960. Data for the mines and mills are presented separately, as shown in the list of tables. The Bureau of Mines is authorized to send questionnaires to the nonmetal mining industry for their voluntary submission of injury and employment data. As the information submitted contributes largely to the promotion of safety in the industry, special effort has been made to ma e these questionnaires as complete as possible.

Jan 1, 1963

The Wainui Mill was conceived as a 60 - 90 t/d central mill to process gold ores of the Thames area of New Zealand from small mines in the district. The ores of the region exhibit various degrees of refractory response to conventional cyanidation leach due to the fineness of the gold, and association with pyrite. The alternative circuits involving cyanidation, flotation, and possible small-scale smelting are examined. The environmental impacts have been audited by the Commission for the Environment and were found to be acceptable.

Jan 1, 1986

By Thomas A. Simpson

Traveling through the moors and valleys of Cornwall, England, one is reminded of the extensive mining activities of the past. Abandoned shafts, remains of granite block wheel houses and engine houses, battered brick stacks, old calciners, overgrown water wheel pits, count house remains, overgrown waste pits, and old portals are gaunt monuments to a once flourishing mining industry. Cornwall is bordered on the north by Devon and occupies the south-western most tip of Great Britain. The Atlantic Ocean borders the promontory; to the north, the mouth of the famous Bristol Channel faces the open sea; and to the south, the English Channel separates the land masses of Great Britain and Europe. This part of England is probably the most extensively mined ground in all of Europe. Such great mines as Dolcoath and Wheel Vor, Consols and South Carodan, Levant and Bottalack, remain legendary in the annals of metal mining in the nineteenth century. Many US mining districts hold close ties with Cornwall, Devon, and Wales through ancestors who emigrated from there to work in US mines in the eighteenth and early nineteenth centuries. Their descendants can be found in many major US mining districts, and their terms, expressions, customs, and methods have left an impact on the US mining scene that remains with us today.

Jan 9, 1981