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By Lawrence P. Goldfarb

The City of Alexandria, Virginia, Public Safety Center (PSC) is a 64,000 square foot facility that houses the Police Department, Office of Sheriff and the Office of Magistrate. In addition, the center includes a detention facility for local and federal inmates, operated by the Sheriff. The PSC is composed of a 3-story building to the west and a 6-story building to the east constructed on a landfill in a wetland area in the flood plains of hunting Creek. The existing ground floor of the 3-story building is a floating slab-on-grade, with the interior and exterior columns, exterior walls and upper floors all supported on belled, drilled shafts. Portions of the floating first floor slab have undergone excessive settlement due to the apparent consolidation of the underlying organic soils. The magnitude of the settlements of the floating first floor slab is sufficient to require replacement of the slab and relocation of a portion of the facility. The rehabilitation was complex and required staged construction, consisting of constructing Auger Pressure Grouted (APG) Piles in low overhead conditions. This paper summarizes the geotechnical conditions that lead to the excessive settlement of the floor slab, the construction of the (APG) Pile foundations in low overhead conditions and the evaluation of potential future settlements.

Jan 1, 2009

With unprecedented worldwide growth and increasing global demand for energy expected to swell by 60 per-cent in the next two decades, mining matters as much now, if not more, than it ever has. This was the consensus at the 110th Annual National Western Mining Conference presented by the Colorado Mining Association, Feb. 12-14 at the Westin Hotel in Denver, CO. The role of coal ? America?s most abundant energy source ? the future of uranium and its possible resurgence in the energy marketplace, the skyrocketing value of gold as well as the issues of health, safety, climate change, legislation and government?s role in mining were all discussed during the three-day conference that operated under the banner of ?Mining Matters.? Barbara Filas, chairperson of the 110th National Western Mining Conference, president of Knight Piesold Co. and former SME president, welcomed the record crowd with an inspiring speech in which she pointed out that although ?most normal folks don?t know what role mining plays in their everyday life, mining does matter. ?Our industry,? she said, ?matters to Colorado. It matters to Colorado because it is a $3-billion industry. It matters to the 13,000 people who are employed directly or indirectly by the industry and it matters to schools that receive more than half of the royalties that are generated by mining.? During discussions of mining?s place in Colorado, the western United States and the world, special attention was paid to coal, uranium and the future of energy. ?It is time to rethink our perceptions about coal,? said Mark A. Smith, president and chief executive officer of Chevron Mining Inc. He spoke during the opening reception in a presentation titled, ?Coal to Liquids: Bridging America?s Energy Gap.? Although coal is America?s most abundant, and cheapest energy source, it is also one of the most scrutinized because of the pollution it causes and recent, and heavily publicized, tragedies that have claimed the lives of some who mine it.

Jan 1, 2008

By Bryan Ulrich

Rroundtable 2009, a Knight Piésold and Co.-hosted roundtable discussion on mine closure and cover design was held at the Red Lion Inn and Casino in Elko, NV on Feb. 12, 2009. Knight Piésold?s Bryan Ulrich and Steve Boyce, as well as Knight Piésold representatives Cynthia Parnow and Corey Conrad from Denver, CO, and Rick Frechette from the Tucson, AZ office were on hand to help facilitate the discussion. The meeting played host to approximately three-dozen attendees from four states. Attendees included personnel from seven mining properties and attendees from corporate offices. The majority of attendees were people directly involved with environmental work on a day-to-day basis. Other attendees were project managers whose jobs involve some level of environmental focus. The purpose of Roundtable 2009 was to exchange ideas and information pertaining to mine closure and cover design associated with almost any aspect of a mining operation. This type of forum provides a less inhibited format for discussion, when compared with traditional conferences and symposia. In the roundtable format, lively discussions are encouraged. This discussion was the fourth in the series of Elko Roundtable events. Previous roundtables pertained to heap leach pad design, construction and operation; design, construction and operation of tailings storage facilities and site-wide water considerations. The initial subtopics for Roundtable 2009 included:

Jan 1, 2009

By John R. Wolosick

MACROPILES are defined as ultra-high-capacity micropiles, with working loads in excess of 250 tons. The piles are typically 9-5/8 to 24 inch (244 to 610 mm) outside diameter. They are drilled and grouted in place, with either large diameter steel bars and/or steel pipe reinforcement. The piles are typically tested to twice the working load. Piles with working capacities of up to 500 tons and tested to 1000 tons have been installed. The paper discusses MACROPILE design philosophy, construction techniques, and two case histories where this innovative foundation system has been installed. Macropiles are descended from micropile technology pioneered in the early 1950s by Fernando Lizzi of Italy.

Jan 1, 2006

By Peter J. Clarke

The Soviet-controlled Government in Afghanistan continued to emphasize development of the country's mineral resources, primarily to supply raw materials and fuel to industrial areas in the Soviet Central Asian republics. In addition to expanding production of natural gas for export to the U.S.S.R., a $600 million2 Soviet-Afghan cooperation project, 1 of 167 such projects established since 1981, was devoted to exploiting the Ainak copper deposit, south of Kabul in Logar Province. Also being developed was the large Hajigak iron ore deposit in the Hindu Kush Mountains, 100 kilometers northwest of Kabul. In addition to these minerals, Afghanistan already produced small quantities of barite, cement, coal, gypsum, salt, and possibly some lapis lazuli. Afghanistan was the world's leading producer of lapis lazuli, a semiprecious gem stone, prior to the Soviet invasion in 1978, but production, although no longer reported, has probably been significantly reduced. It was also reported that Soviet mining engineers and technicians have commenced producing uranium from Lashkangah in the mountainous Khawaja Rawash area near Kabul.3 The Government was also considering mining chromite from Herserak and Mohammed Agha Kulanger, near the border with Pakistan.4 Afghanistan's overall economy remained stagnant in 1983, a result of continuing armed resistance to the Soviet-installed government. The gross domestic product (GDP) was estimated at about $2.8 billion, only marginally higher than the 1982 level. The value of exports was estimated at $720 million, up less than 2% over that of 1982, while imports rose approximately 8% over the same period. Natural gas was by far the leading export, earning about $295 million, up 4% over that of 1982. Approximately 90% of Afghanistan's natural gas production was exported to the U.S.S.R. Gas exports were used to pay the country's debt to the U.S.S.R., and also to pay for its supplies of petroleum products and other goods, which were imported almost exclusively from the Soviet Union. Some of Afghanistan's petroleum products were supplied by the U.S.S.R. as grants in aid, as Afghanistan did not have any domestic petroleum refining capacity.

Jan 1, 1985

By S. Atallah

A survey was conducted relating to the current practices for the classification of hazardous locations in coal preparation plants. Several plants processing bituminous, anthracite and lignite coal in Pennsylvania, West Virginia, North Dakota, Colorado, Montana and Wyoming were visited. Coal preparation plant operations and designers as well as MESA inspectors were interviewed. The National Electrical Code was discussed with selected members of the NFPA committee and electrical equipment manufacturers. Data provided by MESA on fire and explosion accidents in coal preparation plants were examined. The requirements of the pertinent Federal Regulations, National Electrical Code, National Electrical Manufacturers Association and Underwriters' Laboratories were compared and evaluated. This report consists of two parts. Part I: "Analysis and Review" provides a summary of the findings. Part II: "Recommended Guidelines" consists of recommended uniform guidelines that may be used for interpreting the National Electrical Code as it applies to the classification of hazardous areas in coal preparation plants.

Jan 1, 1977

By E K. Leeka

Process control limitations have led to suboptimal performance of the crushing section of Sishen MineÆs Jig Plant. The performance of the PID (proportional-integral-derivative) controller implemented during commissioning was hampered by the relatively small buffer capacity between the crushers and screens. The inability to maintain the tertiary crushing chamber under full choke conditions lead to inefficient crushing and reduced crusher product cubicity.Model predictive control (MPC) was implemented in the tertiary crusher plant in May 2012 and resulted in a throughput improvement of six per cent in its first month. The controller was further optimised and indicated a throughput improvement of 16 per cent during on/off testing in July 2012. The throughput improvement is attributable to the finer crusher product resulting from operating the crusher under full choke conditions and controlled feed rate to the tertiary crusher plant screens. The next step is to couple the model predictive controller, automated gap control system and an economic optimiser to ensure maximised throughput and value from the resource.CITATION:Leeka, E K, 2013. Performance of model predictive control on the crushing circuit at Sishen Mine, in Proceedings Iron Ore 2013 , pp 417-420 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By K C. Williams, A W. Roberts, J D. Prigge

For stockpile design, the flowability and structural interfaces are critically dependant on the stress conditions throughout the pile. Historically, the predictive methodologies for stress determination have been too conservative, which adds inefficiency to the stockpile reclaim interface selections, especially for live reclaim stockpile systems. In addition, accurate pressure profiling throughout stockpile is essential to correctly design the stockpile support structures, which are buried within the stockpile. Such buried structures include trestle legs or columns to support load-out conveyors or the roof of bulk storage sheds. Improved methodologies with respect to the development of the hoop stress condition which exists in material ædrawn-downÆ within the stockpile has been developed. This hoop stress approach has significantly improved the live capacity prediction to over 90 per cent accuracy and improved rathole structure prediction within live reclaim stockpiles. Additionally the methodologies in estimating the vertical and circumferential stress variation acting on buried stockpile structures have been significantly progressed, with experimental testing shown good agreement with the theory.CITATION:Williams, K C, Roberts, A W and Prigge, J D, 2013. Recent developments in stress analysis and live reclaim prediction within iron ore stockpiles, in Proceedings Iron Ore 2013 , pp 501-510 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

CONTENTS:1. Introduct'iona. Previous Accountsb. Summary of Geologyc. Physiography2. Morgan Groupa. Lithologyb. Structurec. Faulting3. The Mineral Deposita. Descriptioni. Size and Shapeii. Compositioniii. Effects of Oxidationb. Relationship to Structurec. Genesis of Ored. Mount Morgan Orebodye. Sugarloaf Orebody4. Granitea. Mount Morgan Graniteb. Town Granite'c. Moonmera Granite5. Calliungal Beds6. Razorback Beds7. Acknowledgments8. References

Jan 1, 1952

By G. M. Ritcey, K. E. Haque, S. H. Lucas

"Laboratory-scale hydrochloric acid leach tests were conducted on an Elliot Lake uranium ore. Hydrochloric acid leaches without an oxidant or with molecular oxygen (i.e., air or pure oxygen gas) as an oxidant favoured uranium and radium extractions. Conditions for maximum uranium, thorium and radium extractions with hydrochloric acid in the presence of sodium chlorate were determined. The highest extractions of uranium (96%), thorium (81%) and radium (91%) were obtained using a mixture of 44.0 kg HCI and 2.5 kg NaCIOJ per tonne of ore at 75°C with 18 hours ' retention.Flowsheets for two-stage leaching are proposed. The residues obtained from the second-stage leach contain uranium (0.002%), thorium (0.006%) and radium (15 to 20 pCi/g). Tailings of this nature are considered suitable for mine backfill, and, if pyrite is removed, suitable for surface disposal.IntroductionThe nuclear energy industry forecasts an increasing demand for uranium. This increasing demand requires not only largescale mining and processing of conventional and complex uranium ores, but also leads to the consideration of new and nonconventional sources of uranium, e.g., black shales, phosphate rocks, granite, sea water and fossil-fuel ash."

Jan 1, 1980

By F. Burat

Large reserves of feldspar ore exist in the Aegean region of Turkey. The main colored impurities in these ores are iron- and titanium-bearing minerals such as anatase, rutile, sphene and ilmenite. In this study, a potassium feldspar ore containing mainly quartz and coloring impurities was subjected to beneficiation tests involving magnetic separation and flotation, which were applied either separately or in combination. Bench-scale flotation experiments using cationic collectors G-TAP and Flotigam V-4343 and using HF and H2SO4 as modifiers were employed to separate feldspar from quartz and to remove part of the titanium impurities. The best results were achieved with a combination of high-intensity wet magnetic separation and flotation. A feldspar concentrate containing 16.28% Al2O3, 10.75% K2O, 2.84% Na2O, 69.97% SiO2 and 0.16% Fe2O3 was produced. A quartz concentrate containing 2.30% Al2O3, 0.48% K2O, 0.42% Na2O, 0.07% Fe2O3 and 96.20% SiO2 was also obtained

Jan 1, 2007

By Reginald Dias

Mining equipment life may be extended through preventive maintenance and the proper application of quality lubricants. There are several practices mine operators should consider implementing to preserve their equipment. An exercise in review — Begin by reviewing original equipment manufacturer (OEM) recommendations regarding servicing and maintenance intervals for each part of the equipment, especially the engine. And the verdict is — If the manufacturer’s recommendations have been followed, good. If not, owners/operators should begin periodic service work on equipment, to help minimize equipment downtime and extend engine life.

Jan 1, 2004

By D. S. Pye, J. P. Gallus

Successful hydraulic pressure treatment of oil and gas wells that have long producing intervals, multiple pay zones, fluid thief zones, or natural or induced fractures has long been a serious problem plaguing the petroleum industry. High fluid-injection rates, straddle packers, ball sealers, and either liquid or solid additives to the treating fluids are being used to cope with this difficult and costly problem.l-6 The use of ball sealers and straddle packers is limited, in practice, to wells that have been completed with perforated cemented casings or liners. Well stimulation with ball sealers and straddle packers is usually successful as long as the cement remains competent. The other techniques of diverting are used with all types of completions. However, there are two significant disadvantages of the high rate method: excessive horsepower requirements, and the need of large treating-fluid volume. Consequently, most well stimulation techniques that involve diverting depend upon ball sealers or granular materials. Liquid diverting agents, and some of the solid ones in use today, frequently will cause formation damage. On the other hand, the most popular particulate diverting agents often are so soluble in the treating fluid that they become largely ineffective; their particle size is severely reduced as they dissolve while being transported through thousands of feet of pipe to the formation face down hole. In our attempts to deal with the shortcomings of these diverting agents, we experimented with a large variety of potentially suitable deformable materials the solubility of which could be controlled. Following are the criteria for the diverting agent sought: 1. The material must be effective in reducing fluid loss to thief zones, including existing fractures and very high permeability layers in the formation to be pressure treated. 2. The material must have enough strength to bridge under the treating pressure. 3. The material must be insoluble or slowly soluble in the treating fluids so that the particles retain sufficient size to be effective after they reach the formation face. 4. The material must be completely soluble in the produced oil or condensate liquid so that it can be removed readily; it must not cause formation damage. A number of products consisting of various polymers blended with waxes and other solid hydrocarbons were examined. All these materials satisfied the criteria for a diverting agent and also exhibited some degree of plastic deformability. On the basis of initial tests of strength and hardness, several blends of wax and polymer were selected for extensive testing in the laboratory and the field. These compounds have congealing temperatures ranging from 140 to 190F; they are insoluble in water and soluble in oil. They conformed, therefore, to the criteria specified for a theoretically superior diverting agent. Laboratory and field tests were conducted using these wax-polymer materials to demonstrate that the use of a deformable diverting agent can significantly improve fluid diverting performance. Data in this

Jan 1, 1970

By Holdgate G. R, Thompson B. R, Webster R. L, Bolger P. F

The Gippsland Basin in south-eastern Australia has an area of approximately 46 000 sq km. It is one of the world's major coal and petroleum bearing basins, with most of the former occurring in the smaller one fifth on-shore part. The stratigraphy, structure and economic resources of the Tertiary sedimentary pile is now well known through extensive drilling for coal and petroleum. In contrast, the older Cretaceous sequences through their lesser economic importance are relatively less explored. The sedimentational history of the Gippsland Basin has largely followed along similar lines of development to the many other southern Australian basins since the Cretaceous break-up of Gondwanaland. However, the scale of accumulation of coal and hydrocarbon source rocks is unprecedented and differentiates this basin, for reasons less well understood, from the others. Large scale open cut brown coal mining since the late-1920s has been carried out in the western extremities of the basin, while vigorous extraction of some two thirds of Australian petroleum products taken place in the offshore part. Brown coal seam thicknesses and economically winnable reserves are huge and outrank most other brown coal basins of the world. Development of the resource currently meets the need for electricity generation throughout the State of Victoria, but other future developments such as conversion to oil, being investigated.

Jan 1, 1992

By James A. Mason

The State of California has instrumented numerous buildings, bridges, and dams throughout the state with earthquake recording devices. These accelerometers are strategically placed to measure the response of the structure to a specific seismic event. This comprehensive program enlightens the field of seismic engineering after each earthquake. The Office of Strong Motion Studies, California Strong Motion Instrumentation Program, a sub-branch of the Division of Mines and Geology, provides a professional service unequalled in the world. Within hours of a local earthquake, a preliminary report with the epicenter / hypocenter, structural damage, and time history records are available to all interested parties. The included partial report in the appendix, see section 5.1, is one of the reports that C.S.M.I.P. produced after the Loma Prieta Earthquake of October 17,1989. The diagram on the cover is even of interest. This is a small portion of San Francisco. The values on the diagram are the recorded maximum horizontal ground accelerations at that location in the city. For example, the acceleration at Yerba Buena Island was 0.06g. (The "g" refers to the acceleration of gravity. Thus, a 0.06g acceleration refers to the force, F=m*a, that the structure would experience. For this case, the force would be six percent, 6 % , of the mass of the structure.) Yet, directly on the other side of the Bay Bridge, at Treasure Island, the acceleration was 0.16g. Yerba Buena Island is a natural island composed of hard granular material. Whereas, Treasure Island is a man-made island of imported filled. Here one can see the absorption / transmission difference between hard material, which interact with short seismic wavelengths, and soft cohesive material, which interact with long seismic wavelengths.

Jan 1, 1993

By Rixon K. L

Hargraves (1983) has reviewed the phenomenon of instantaneous outbursts of coal and gas with special attention to Australian occurrences. The purpose of this discussion is to highlight some problems and omissions in his review that reflect particularly on the authors' structural geological investigations of outburst-prone coal seams.It is surprising to find that much of the authors' reported work has either been glossed over or the results distorted by Hargraves (1983) and it is, therefore, important to clarify the contribution that structural analysis of coal seams can make.For many years it has been known that faults provided preferred loci for gas outbursts (for example, Briggs 1920-21) but the roie that faults played in outburstprone seams was unclear. The present authors reviewed the association of faults and outbursts drawing upon local investigations and the world-wide literature (Shepherd et aI., 1981), and discussed some wideranging aspects that result from the high coincidence of faults and outburst sites. Without repeating large segments of this article the authors will discuss four aspects of coal seam faulting and fracturing.

Jan 1, 1983

By L. V. Clark, Arthur La Motte

"INTRODUCTION The U. S. Bureau of Mines in 1930 and 1931 made a study of the properties and characteristics of liquid-oxygen explosives (L.O.X.) at the request of one of the largest users, in order to determine and eliminate the hazards attending its use.This report deals with the examination of absorbents for L.O.X. to (1) determine their most desirable and most undesirable characteristics, (2) to find ways and means of desensitizing absorbents to mechanical shock, and (3) to determine the effect that such desensitization of absorbents has on the explosive Characteristics of L.O.X.ABSORBENT MATERIALS The absorbent used in driving the Simplon Tunnel, the earliest project in which L.O.X. was used, was composed of crude petroleum, soot, and kieselguhr. During the World War, powdered cork, soot, sawdust, powdered straw, or other similar powdered materials were mentioned in the German military instructions for use of ""liquid air"" explosives. At that time the common types of absorbent, materials were compounded ones containing the above ingredients as well as kieselguhr, paraffin, gas oils, charcoal, bituminous coal, etc.Kuryla and Clevenger4 investigated absorbents of the above type and made the following statement concerning them:"

Apr 1, 1932

By Elbridge W. Gresseth

Rock deformational structures in a deep mine were analyzed by petrofabric techniques to learn (1) the relative magnitude and direction of the principal stresses involved in tectonic deformations prior to mining, (2) the preferred orientation of rock planar discontinuities which define rock anistropy prior to mining, and (3) the relationship of mining-induced rock failure to inherent rock stresses and inherent rock anisotropy. Rock fabric elements used for petrofabric analysis consisted of bedding planes, faults, joints, fractures, foliation, sericite plane (001), quartz axis [0001], quartz deformation lamellae, and microfractures. Structures and structural symmetries from different areas within the mine and from different scales of observation were compared to learn the nature of rock anisotropy and the orientation of the principal stresses defined by rock deformations. Analysis of such fabric as regional and macroscopic faults, b-c joints, quartz [0001], sericite (001), and microfractures, indicate that during the epochs of tectonic deformation, the maximum and minimum principal stresses were horizontally oriented and acted along northwest and northeast axes, respectively. This condition of regional stress appears to have continued during folding and the associated period of faulting. The most recent tectonic deformation represents a rotation of the minimum principal stresses into a vertical position, as shown by the development of a tensile joint system, quartz deformation lamellae, and microfractures. Good interscale correlation and statistical homogeneity of tectonic fabric indicate a stress field homogeneity in this area during tectonic deformation. Rock physical anisotropy is genetically associated with tectonic fabric and consists of preferentially oriented planar discontinuities intersecting along a nearly vertical axis. The mining-induced deformations were correlated with the inherent rock anisotropy which either directly controls or greatly affects their development. This phase of rock deformation shows a greater degree of stress field heterogeneity than was the case with tectonic deformations This is explained as a result of nonconfinement afforded by underground openings and the increase in ground stresses due to mining activity"

Jan 1, 1968

By D. Nyungu

Despite observations of spalling and damage of mine excavation wall rock in the Bushveld Complex (BC) over the passage of time, there have been very few time-dependent or creep tests carried out in South Africa on rock, particularly on BC rock types. The research described in this paper deals with the investigation of stress and strain conditions influencing spalling of wall rock in BC mine excavations, and the influence of time on the tensile strength of several BC rock types. Time-dependent laboratory testing of BC rocks was carried out in indirect tension. The results show that the magnitude of the tensile strength of BC rock types is approximately 5% of their uniaxial compressive strength magnitudes. The average long-term uniaxial compressive strength of the BC rocks, interpreted from the axial stress-volumetric strain graphs, is 56% of the UCS value. The long-term tensile strength is shown to be less than 70% of the normal tensile strength. Extension strains at tensile strength failure ranged between 0.16 and 0.21 millistrain. Values corresponding with the long-term tensile strength are less than 70% of this range, namely, 0.11 to 0.15 millistrain. These results represent new knowledge, since such rock testing and analysis does not appear to have been carried out previously on BC rock types. Elastic numerical modelling was carried out to illustrate the extents of tensile stress zones and extension zones around of typical BC mine excavations. The models showed that large zones of extension strain can occur around BC excavations, and that the magnitudes of the extension strain can substantially exceed the critical values determined from the laboratory testing. The implication of this is that there are substantial zones surrounding BC mine excavations that will be prone to time-dependent spalling conditions and perhaps more significant failure.

Jan 1, 2014

By John C. Machisak

STATISTICAL data on injuries and employment pertinent to metal mines and to their mills, and/or processing plants are presented in this Information Circular for the calendar year 1960. The information pertains to metal mines, as well as ore-dressing plants and primary nonferrous smelters, refineries and reduction plants, and their auxiliary works. These data are voluntarily submitted annually to the Bureau of Mines by the operators, and contribute greatly toward the promotion of safety in the mineral industries. The data presented are classified according to the principal mineral produced and include information on copper, iron, lead-zinc, gold-silver lode, gold placer, uranium-vanadium and miscellaneous metals. A breakdown of miscellaneous metals by commodities is shown in table 19, page 41. The data also relate to workers engaged in production, exploration, development, construction, and maintenance and repair work, as well as supervisory personnel and office- workers at the mine or plant site. Injury and employment data at metal mines and metallurgical plants in the United States for 1960 are shown under the following general sections:

Jan 1, 1963