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By David S. Yang, Osamu Taki

The innovative Soil-Cement Mixing Wall Technique, developed independently in Japan, consists of mixing in-place soils with cement grout using multi-axis augers and mixing paddles to construct overlapping soil-cement columns. The applications of overlapped soil-cement columns include cutoff walls for groundwater control and structural diaphragm walls for excavation support. The special features of this technique include water tightness, versatile strength design, and efficient installation in subsurface materials varying from clayey soils to cobbles or soft rocks. Through the introduction of two recent subway projects in Japan, this paper presents the design parameters, construction procedure, quality control and performance of soil-cement wall for excavation support and groundwater control.

Jan 1, 1989

The design, specification, and performance evaluation of the Communications and Location portions of a Coal Mine Rescue and Survival System are described. The work was performed as part of a nine month effort to develop a mine rescue and survival system using existing technology and state -of-the -art hardware as recommended by the National Academy of Engineering. Three basic subsystems were developed, one for survival, one for communications/location and one for rescue. This report and related equipment manuals describe only the Communications/ Location Subsystem which was designed, fabricated, and tested by the Westinghouse Georesearch Laboratory in Boulder, Colorado. Two basic technologies were used. Electromagnetic signals propagating through-the-earth provide voice downlink and coded beacon up-link communications. Seismic methods were developed to provide means for locating trapped miners. Seismic signalling also provides a backup means for communications. Parallel development programs for the electromagnetic and seismic portions of the system were conducted. The resulting hardware and software have been partially tested in coal mines and under simulated emergency conditions in order to evaluate system performance. The results of these tests are discussed. Further testing is recommended in order to establish quantitative performance limitations tinder a variety of environmental conditions and to develop methods for improving system performance.

Jan 1, 1971

By Atsushi Shibayama, Toyohisa Fujita, Luo Lin, Toshio Miyazaki

A novel process is developed in this study for separation of tungsten and vanadium from a leach solution of tungsten alloy scraps. Specifically, a magnesium salt combined ammonium solution is employed to precipitate vanadium and impurities in the purification of the leach solution. This separates vanadium from tungsten by rejecting tungsten in aqueous solution. Finally, tungsten is recovered as the form of ammonium para-tungstate (APT). Vanadium is recovered as the form of ammonium meta-vanadate(AMV).

Jan 1, 2003

By Charles Findlay

As one of its projects for degasification of major panels of coal prior to mining within them, the Bureau of Mines conducted methane emission studies during development of a set of three headings 1,800 feet in a major coal panel (2,700 by 3,500 feet) which had been completely isolated by sets of main headings for 12 months in the Federal No. 2 mine (Pittsburgh coalbed) in northern West Virginia. Similar emission studies were conducted in the development of two sets of main headings in virgin coal areas nearby. Comparing the two sets of data indicated that the isolated coal panel had been degasified by approximately 70 percent.

Jan 1, 1973

By Dean H. Ambrose

This paper presents the results of a study using computer human modeling to examine machine appendage speed. The objective was to determine the impact of roof bolter machine appendage speed on the likelihood of the operator coming in contact with. A contact means two or more objects intersecting or touching each other, e.g., appendage makes contact with the operator?s hand, arm, head or leg. Incident investigation reports do not usually contain enough information to aid in studying this problem and laboratory experiments with human subjects are also not feasible because of safety and ethical issues. As an alternative, researchers developed a computer model approach as the primary means to gather data. By simulating an operator?s random behavior and machine?s appendage velocity, researchers can study potential hazards of tasks where it is not possible to perform experiments with human subjects. Analysis information is helpful to the mining industry in terms of making recommendations that reduce the likelihood that roof-bolter operators experience injury due to contact with a moving boom. Data analysis of roof bolter simulations show that the virtual-operator?s response time has little effect on the number of contacts experienced. Based on frequency and cross-tabulation, regardless of other variables, contact incidents were always greater when the boom was moving up, were always greater on the palm, and were always greater for the boom part of the machine. Also, regardless of boom speed, the 25th-percentile-sized operators experienced more contacts than did other operator sizes. Furthermore, regardless of boom speed, the 152-cm mine seam experienced more contacts than did other seam heights tested. Results of a survival analytic approach suggest that controlling the boom speed is the most important factor in determining the risk of an operator making contact. Based on the data collected, boom speed greater than 41 cm/s results in a substantial increase in risk to the roof bolter operator and should probably be avoided. At speeds less than or equal to 25 cm/s are associated with a more modest relative risk, which represents an acceptable level of risk. Also, at speeds between 25 and 41 cm/s, there could be a particular boom speed in this range at which a significant inflection point in the relative risk estimates occurs. Based on the results, this issue needs to be addressed by future research.

Jan 1, 2003

By Phil Pennington, D. Jack Adams, G. Ward Wilson, Virginia T. McLemore, Luiza Aline F Gutierrez, Rodney Shields, Steven Lockwood, Samuel Tachie-Menson

Microorganisms are directly or indirectly involved in many chemical alterations and in the decomposition of minerals required for their growth. Microbial dissolution of sulfide minerals under acidic conditions can produce over 1,000 times more Acid Rock Drainage (ARD) than chemical action alone. Microbial actions can cause precipitation of minerals, adsorption or release of metals, and formation/destruction of organic-metallic complexes. Soluble minerals can serve as oxidizing substrates, electron donors/acceptors in redox reactions, and can be directly involved in cell metabolism. Microorganisms and microbial oxidation-reduction reactions and their contribution to mineral mobilization and stabilization will be discussed.

Jan 1, 2005

By J. H. Adkins

The goal of this program was to produce a set of baseline health and safety training materials that could be used by the metal/nonmetal mining industry to reduce injuries and to comply with federal training requirements. The materials developed are arranged in a two level outline format. The first level provides the title, course goals, background and topical outline while the second level provides a detailed outline of the course content. Visuals, designed to portray miners in a positive, attractive fashion, were done in simple line drawing so they would reproduce for handouts without loss of quality. Each of the required units in the Baseline Guides have one or more self-checks. These are designed to be suggestive of evaluation techniques the users can develop for themselves. An instructors guide and a mining terms glossary are included. In a second phase the program developed performance based training guides for Annual Retraining and Experienced New Hires in the Underground Salt Industry.

Jan 1, 1983

By Robert B. Johnson

The refraction seismic method has been used as an indirect means of exploring for fluorspar in southern Illinois by the Illinois State Geological Survey. Use of the method has been restricted to those areas where mineralization is associated with faults, a restriction necessitated by the operating principles of the refraction method. The seismic data enable the interpreter to locate fault zones in the subsurface and, under ideal circumstances, to make estimates of dip direction and magnitude and vertical displacement provided the local stratigraphic units are known and are geophysically recognizable. In this instance, refraction seismic exploration has been successful in the surface mapping of well-developed faults, both simple and complex with which fluorspar may or may not be associated. However, less clear results have been obtained where faulting has been less severe and where there are numerous accompanying mineralized joints.

Jan 1, 1964

By Brooke T. Mossman

Asbestos fibers are highly fibrous silicate fibers that are distinguished by having a large aspect (length to diameter) ratio and are crystallized in an asbestiform habit that causes them to separate into very thin fibers or fibrils. These fibers are distinct from nonasbestiform cleavage fragments and may appear as thick, short fibers which break along cleavage planes without the high strength and flexibility of asbestiform fibers. Since cleavage fragments of respirable dimensions have generally proven nonpathogenic in animal studies, little data exists on assessing well-characterized preparations of cleavage fragments in in vitro models. The available studies show that cleavage fragments are less bioreactive and cytotoxic than asbestiform fibers. © 2007 Elsevier Inc. All rights reserved. Keywords: Asbestiform; Cleavage; Fibers; Fibrous

Jan 1, 2007

By Jorge Blacker Bendezú

Existen historias registradas sobre descubrimientos de ciertos elementos de la Química que mostraban propiedades especiales de difícil identificación. En este grupo de elementos químicos (17) se encuentran "las tierras raras" que, conjuntamente con otro grupo de sustancias estratégicas, contribuyen al cabal desarrollo de la ciencia y su correcta aplicación mediante su permanente progreso tecnológico. Por ello, el presente texto señala los mitos y realidades sobre estas "tierras raras" y otros metales estratégicos (comercio, alternativas de explotación y costos)

Jan 1, 2014

By H. M. Chikashi

Keywords: Pyrometallurgy, furnace, bath agitation, regression analysis, entrainment This paper presents the results of linear regression analysis of the influence that each component of slag has on the losses of copper in slag-cleaning-furnace slag. Data used for the analysis are actual plant data collected over the past two years of operation. Facts obtained from the study will be helpful for smelter management to control these components in the flash smelting furnace feed and slag, to levels which will enable better control of copper in slag, and smoother operation of the KCM slag-cleaning furnace.

Jan 1, 2011

n the early days of the Hauraki goldfield (1866 to 1889) almost the only system of ore treatment was wet crushing followed by copper plate amalgamation. A further saving of bullion was in most cases obtained from the tailings by means of pans or berdans. Though this system was not always as efficient as might have been desired it answered fairly well for the bulk of the gold-bearing quartz of the Thames and Coromandel districts, where the gold occurs chiefly in the form of visible particles, and there is not a great deal of silver. It failed, however, with most of the ore found in the Upper Thames or Ohinemuri district, especially in the Karangahake and Waihi portions of the field. In those days the cyanide process was not, and the usual prescription of the mining " expert" was smelting. At Karangahake, many attempts were made to discover a payable method of treatment for the so-called" refractory" ore, but on thewhole with very 'little success, and the district struggled along for a number of years without adding very materially to the production of gold in New Zealand. At Waihi, the Martha Co.'s stamp battery treated by wet crushing and copper plate amalgamation some 18,000 tons from the Martha Reef, worth probablyat least £4 per ton, but the average return was considerably less than £1 per ton, a sum which barely paid working, expenses, and consequently the shareholders were glad...

Jan 1, 1903

By Julian Malnic

Transplanting the steps used in exploring and developing mineral deposits on land into the marine environment will help developers. While familiar to oil and gas explorers and many other sea-based industries, the marine environment is so alien to the 90s terrestrial miner that the phrase ?terrestrial mines in the sea? is useful for reinforcing the fundamental parallels in mining sulphides at sea and on land. As on land, the processes of ?pre-feasibility study? and ?feasibility study? will determine the economics of mining a deposit. For many, the step into the sea can detract from the need to follow these familiar and recognised steps used when any new deposit is found on land. The technology to mine sulphides in the 1500 to 2000 m depth range exists. Currently, it is not found in a single, integrated and commercially available system but every element available to build such as system is. Transplanting the thinking of the leaders of the terrestrial mining industry into the sea will perhaps be the greatest challenge and reinforcing the basic steps of discovery - pre-feasibility through to feasibility is the best way to achieve this. After all on land one doesn?t ask ?Can we profitably mine it?? before one can authoritatively answer ?What have we found??. Research by Nautilus Minerals Corporation suggests that the mining of seafloor massive sulphides (SMS) will not only be profitable but potentially lower in both capital and operating costs than prevail in most terrestrial deposits. Nautilus is also acutely aware that with the first SMS deposits under title, it will be setting the standards for seafloor mining into the new millenium. Indeed, we have trained on us not only the eyes of the mining industry waiting to see if SMS deposits really do offer radically better returns, but other stakeholders of the sea and the capital markets. Mistakes by any SMS developer could land all developers in ?hot water?. The rush to exploit our deposits for economic gain will be tempered by ensuring there is adequate public debate and consultation for our environmental code. Failure in any facet of a marine mining development could set back the move to the ocean floor.

Jan 1, 1998

By M. F. Bradley, G. M. Schoen

The Magmont Mine, a 50/50 venture between Cominco American Incorporated (the Operator) and Dresser Industries, Inc., (Halliburton), is a metallic mining and milling facility in the new lead belt of Missouri. The mine is located approximately 100 miles southwest of St. Louis. Legislation passed in 1992 by the Missouri legislature requires all metallic mining and processing facilities to apply for a Metallic Minerals Waste Management permit (MMWM) for their waste facilities. Regulations were subsequently promulgated by the Missouri Department of Natural Resources (DNR). Cominco obtained a MMWM permit (MM-006) from the Missouri DNR in 1992.

Jan 1, 2001

By Bruce Pinkston

This report presents a description of the Prototype Demonstration Vehicle developed under U.S. Bureau of Mines Contract No. JO 366003, "Improving Man Transit Safety". This vehicle was constructed to assess the feasibility of a set of equipment related guidelines which were drafted in Phase I of the same contract. State-of-the-Art improvements were embodied in such areas as collision survivability, occupant comfort, and multiple mode (on and off rail) operation. The electric battery-powered vehicle carries a twelve man section crew at speeds up to 12 mph. The description of the demonstration vehicle is presented in Volume I. Safety Guidelines are presented in Volume II.

Jan 1, 1981

By L. J. Moore

Introduction Hydrometallurgical solvent extraction (SX) processes – featuring large quantities of combustible or flammable organic solvents - are common in the mining industry for recovering non-ferrous metals such as copper, nickel, cobalt, uranium, tungsten, iodine and lithium. Recent fire loss incidents and the widespread use of sub-grade tank farms and piping trenches, plastic piping, poor drainage, and closely spaced buildings demonstrate opportunities to improve the use of Inherent Safety (IS) in this industry. The mining industry has designed and constructed facilities with an emphasis on personnel safety, production efficiency and cost effectiveness. The use of IS to eliminate or minimize property fire exposures has not seen widespread practice. Lessons learned from the mainstream CPI have not been communicated or applied. As an example, copper SX plants have consistently used design of gravity flow as a cost and production-effective solution for transferring liquids and minerals through the process. In fact, Jergensen1 recommends to “utilize gravity to the fullest extent possible” in design of SX plants. This philosophy has been achieved by laying out SX plants with process equipment at different grade levels so that solutions can flow “downhill”. Because of the use of large quantities of flammable liquids and the potential for these liquids - if released – to flow unimpeded into other areas – gravity SX processes represent severe inherent fire consequences unless costly barriers, drainage and channeling are also provided. It appears that little thought has been given to the fire protection consequences and challenges of this design feature during the evolution of SX plants and most copper SX plants constructed today use some form of a sub-grade processing area (tank farm) and one-way gravity flow. While this layout is used to assure a cost effective operation it has resulted in significant exposures to high value production. The use of sub-grade production units is an inherently unsafe layout where flammable liquids are used and is a layout that would rarely if ever be used today by the mainstream CPI. Gravity-assist layout is only one example where copper SX plants have been designed and constructed without IS in mind. The use of combustible and frangible corrosion-resistant materials – such as glass, wood and plastic - for flammable liquid storage, processing and piping systems has significantly increased the hazards of these facilities. These materials of construction are not rigorous and allow for rapid failure and release of flammable contents during fire exposure. The use of combustible or frangible systems to handle or transport flammable liquids is not a practice seen today in the CPI.

Jan 1, 2006

By Stefan Larsson, Sebastian Adevik, Sadek Baker, Razvan Ignat

"Abstract Uncertain strength, deformation and flow properties in dry deep mixing columns often lead to conservative choices concerning design values where the design is regularly complemented with a surcharge fill. The surcharge not only leads to increased cost but also to logistical problems where the surcharge is a physical obstacle. The deformation properties of a ground improvement were studied by means of two small embankment load tests. The settlement measurements were also used in FEM analyses, where the effect of surcharge on creep settlements was investigated. Based on the results, the effects of the surcharge were considered negligible and could safely be ignored. The project is an example how the contractor can use a field test as an effective design approach.IntroductionGround improvement of soft soils with dry deep mixing columns, or lime-cement columns, is often combined with a surcharge fill. The main reason for using a surcharge is to force the primary settlement and some of the secondary settlement that would have occurred under the final embankment height alone, to take place under the surcharge loading. Another reason is to level out uneven settlements. Strength and deformation properties in improved soil cannot be sufficiently assessed in advance, before columns have been tested on-site, and this uncertainty often lead to conservative choices concerning design values. In order to compensate for a slow forecasted consolidation process, the design is regularly complemented with a surcharge. The surcharge not only leads to increased cost but also to logistical problems where the surcharge is a physical obstacle.Extensive research undertaken by Åhnberg (2006, 2007) shows, by means of triaxial and oedometer tests, that cementation processes and a load acting on the columns during hardening, makes the improved soil to behave as a heavily over-consolidated soil due to an increase in quasi pre-consolidation pressure. The effects of using a surcharge on the time for consolidation and creep properties are thus probably small, since the stress level does not normally exceed this quasi pre-consolidation pressure. A study presented by Venda Oliveira et al. (2013) shows that the stress level within small ranges has limited effect on the creep properties.This paper presents a case study where the deformation properties of a ground improvement using dry deep mixing columns was investigated by load tests on two small test embankments. The tests were performed at the Interchange Värtan project site, which is part of the Norra länken infrastructure project in Stockholm. The tests were not performed as a research project but simple load tests performed by the contractor with the purpose of rationalizing the design delivered by the client. One purpose of the load tests was to assess the deformations when the columns are loaded temporarily by overlaying concrete works. Another purpose was to provide some input data to a study of the effects of using surcharge on creep settlements. The analysis was conducted as finite element modeling using the commercial code PLAXIS, where creep settlements can be simulated using the built-in Soft Soil Creep model."

Jan 1, 2014

By Abraham Naupari

El presente texto señala la metodología utilizada desarrollada por CENTROMIN PERÚ para determinar el rendimiento del equipo pesado empleado en el tajo McCune de Cerro de Pasco, evaluando las diferentes actividades dentro de las operaciones para optimizar la utilizacion de las mismas. También se describen las condiciones actuales de operación del equipo, los estudios de tiempo de operación, la determinación del rendimiento del equipo y el rendimiento propuesto del mismo.

Nov 20, 1978

1. Paper1?Identification and enumeration of asbestos fibers in the mining environment: mission and modification to the federal asbestos standard Arthur M. Langer Asbestos-related disease is increased with cumulative exposure (the concentration of asbestos in the air and duration of exposure). The maximum duration is assumed to be a working lifetime so federal agencies control cumulative exposure by limiting the airborne concentration of asbestos fibers equal to or greater than 5 lm in length. Air samples are collected in the environment of interest by entraining the airborne particulates including fibers on membrane filters and then counting the number of fibers using phase-contrast light microscopy. In addition to length, the fibers must have a length to width ratio of at least 3 to 1. This ratio is also referred to as the aspect ratio. Some counting strategies placed an upper limit on the fiber width restricting the counting to respirable fibers. Airborne asbestos is controlled by monitoring a sub-population of the airborne asbestos. No asbestos fibers shorter than 5 lm or fibers of any length having widths less than the resolution of the light optical method are counted. In the non-occupational environment, the Environmental Protection Agency requires the use of analytical transmission electron microscopy and fibers and counting fibers with lengths of 0.5 lm or greater and aspect ratios of 5 to 1 or greater are counted. The permissible exposure limit for asbestos has been reduced by more than 120-fold since 1969, when the standard was 12 fiber/ml and the current monitoring methodology was developed. The manufacturing and mining worksites are regulated by two different federal agencies and the asbestos exposure limit was higher in the mining environment until recently (Mine Safety and Health Administration 30 CFR Part 56, 57, and 7, Federal Registry, February 29, 2008). Currently the permissible exposure limit (PEL) is the same in both types of workplace and it is 0.1 fibers per milliliter (fiber/ml) over an 8-h shift as a time-weighted average (TWA). A milliliter (ml) is equivalent to a cubic centimeter (cc) and sometimes this standard is reported as 0.1 f/cc. As the phase-contrast methodology was used to monitor lower exposures and environments, other fibrous mineral particulates were incorrectly characterized as asbestos. These occurred in talc deposits and taconite ores from the Eastern Mesabi Range.

Jan 1, 2008

By Hendrick A. D. Kirsten, A. Clayr Alexander

Stillwater Mining Company is currently developing a second underground palladium and platinum mine approximately 21 km (13 miles) west of their existing Nye operation in the Bear tooth Mountains of southern Montana. Portals for the two access tunnels required at the new site were excavated in limestone talus to accommodate4.6 m (15 feet) diameter tunnel boring machines. A review of the technical design, field conditions and construction of the portals is presented.

Jan 1, 2001