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This Bureau of Mines report reviews the information presented at the Sixth Mineral Waste Utilization Symposium cosponsored by the Bureau of Mines, U.S. Department of the Interior, and the IIT Research Institute. Environmental scientists and engineers from nine countries participated in the symposium, which was held May 2-3, 1978, at the Chicago campus of IIT Research Institute. The 56 papers presented on the reclamation and recycling of mining and mineral wastes, municipal solid waste, industrial wastes, and scrap metal are summarized herein.

Jan 1, 1980

By S. Z. Pethö

Pillar extraction at shallow depths with small pillars that were not originally intended for secondary extraction can provide a huge benefit to the coal mining industry in those areas where a significant percentage of the remaining coal reserves are locked up in small pillars at shallow depths and where opencast mining methods are simply not as cost-effective and practical to implement. A system considering all of the pertinent geotechnical and mining aspects for the safe and efficient pillar extraction of small pillars at shallow depths at Xstrata Coal South Africa (XCSA) has been further developed and implemented as part of an ongoing improvement process addressing all of the relevant legal and associated risk aspects. This work follows on from the previous pillar extraction work carried out at the ATC, Boschmans, and Spitzkop Collieries. The process involved a number of in-house workshops and sessions arranged with all key personnel from Tavistock Colliery, and also included Professor Nielen van der Merwe of the University of the Witwatersrand, a world renowned authority on pillar extraction, towards reviewing and developing the Modified NEVID pillar extraction system employed previously at Boschmans Colliery. The system is currently being employed at Tavistock Colliery with success and no major accidents, with around 655 000 t of coal having been successfully extracted from the pillar extraction panels.

Jan 1, 2012

By R M. Ennis, J. C. Botham

This paper is one of a series pre-pared to study the role of fuels and reductants in metallurgical processes, especially from the viewpoint of Canadian requirements. The object of these studies is to provide a reason-ably authoritative interpretation on the interrelation of fuels in light of the considerable changes that have taken place in the Canadian energy field during the past few years. Previous papers in this group have dealt with the problem generally, and specifically in terms of the development of the iron and steel industry of Western Canada. These latter papers, presented at the Symposium on Iron and Steel in Western Canada held in Edmonton, Alberta, on September 8-9, 1959, surveyed the ferrous processes of interest for use in Wes tern Canada, especially with regard to solid fuel requirements. At that time it was evident that there was a need for a similar study of the fuels aspect of the non-ferrous metals industry.

Jan 1, 1961

By Charles L. Guild

I will add a few facts about the use and development of the Osterberg Test Load Cell and my association with Jorj. I first met Jorj in 1965 when the Guild Construction Co. drove 12" diameter cast-in-place shell piles for him at the Marquette Cement Co. in Nashville, Tennessee. When I met Jorj at the DFI Trustee's meeting in 1985 at Longboat Key, Florida, he showed me a sketch of his idea about using a test cell at the bottom of a caisson to test the end bearing and side friction on a caisson. He had made a successful trial test in Case International's equipment yard and wondered whether a similar device could be made for a driven pile. At first I was skeptical that it could be done but after thinking about it overnight I told him I felt it was feasible and we would do some work on it. At that time, there was a large bridge job going out for bid in Rhode Island using 14" square prestressed concrete piles'. Based on a record of the Guild Construction Co. Inc. driving over 3,000,000 feet of piling on work for the State of R.I., we felt we would have an excellent chance to be allowed to use them so we designed, detailed and fabricated three for 14" square prestressed concrete piles. As things worked out, we did not test them on this job and have not to date.

Jan 1, 1989

By W. D. Johnston, T. P. Thayer

THE minerals that collectively are known as chromite form an isomorphous series of the general formula (Mg,Fe) 0. (Cr,Al,Fe) 203. So wide is the range in chemical composition in this group that chrome ore consisting entirely of the mineral chromite may range from less than 30 pct to more than 60 pct Cr203. The most comprehensive published data on the chemical com- position of chromite are by Stevens,62 who made complete analyses of 52 samples of chromite concentrate from many localities in North, Cen- [ ] tral, and South America. These samples were mechanically purified to remove associated silicates and might be regarded as the cleanest chromite that could be obtained by any mechanical milling process. Fig 1 shows the predominant zone of isomorphism, within the triangular prism of composition defined by the mineralogical end members of the series, wherein his analyzed samples fell.

Jan 1, 1949

By J. M. Ekenes

New approaches that increase hydrometallurgical recovery from refractory minerals in below-mill-cut-off-grade sulfide copper ore can add significant value, improve profitability and increase ore reserves. This paper describes the development and implementation of an engineered heap (EH) approach to leaching low-grade, chalcopyrite-bearing ore at Freeport-McMoRan?s mine in Morenci, Arizona. The technical evolution of the engineered heap concept is described together with the challenges and benefits following implementation.

Jan 1, 2012

By Matthias Pulsfort, Markus Herten, Rolf Breitenbücher, Claudia Fierenkothen

"Secant bored pile walls are frequently used as retaining walls in watertight excavations to cut off ground water aquifers and are subsequently exposed to ground water pressure loading in addition to earth pressure loads. To avoid extra loading from ground water pressure in soils with limited permeability, it can be useful to arrange drainage windows within secant bored pile walls by means of single primary piles filled with porous concrete without reinforcement cages, which usually have to be placed within casings in submerged conditions. This concrete may serve as a horizontal arch between the reinforced secondary piles, but it must however enable vertical draining between load carrying construction beams and the bottom of the excavated pit. In the present submission, the results of several material tests with different mix designs of porous concrete with certain admixtures are presented together with first and important experiences with a wellsuited placement technique for porous concrete casings in small- and large-scale laboratory tests. It can be shown that the usual placement technique of employing a tremie pipe is not suited for this type of unsaturated concrete. Instead, pouring with a particular kind of cone and an open conductor pipe has proven successful.Additionally, special testing methods are currently developed for judging the suitability of the desired concrete mix design in preparation for an upcoming real-scale experimental pile installation in Germany.1. INTRODUCTIONRetaining walls are often built as secant bored pile walls in order to cut off aquifers saturated with groundwater against deep building pits. In soil types with relatively low permeability, however, seepage flow may be permitted, because the quantity of groundwater to be pumped is limited, and the range of influence due to dewatering is not reaching far. Thus, the hydrostatic water pressure on the retaining wall can be considerably reduced, leading to a more economic design (see Fig. 1).In unsaturated soils, the dewatering effect can be achieved by means of porous pervious concrete with a uniform grainsize distribution of aggregates typically placed in a borehole under dry conditions. With regard to the use of porous concrete to be placed at the ground surface in road pavement applications, experience is sufficiently available as shown, for instance, by Neithalath et el. (2010). However placing the porous concrete in a bored pile using a tremie pipe under submerged conditions is a challenge and a completely new approach, because there is a considerable risk of segregation of the fresh concrete, separating the cement lime paste from the aggregates when in contact with water and leaving only neat gravel on the one hand as well as a tight cemented area at the bottom of the pile on the other hand. If this concrete placement is successful, additional dewatering by means of extra wells behind the retaining wall can be avoided. Of course the seepage flow in the adjacent soil needs to be regarded seriously."

Jan 1, 2017

By Christopher J. Bise

INTRODUCTION The transportation of men, supplies, and mined material from an underground operation is the connecting link between the mine plant and the surface plant. Unless the mine is accessed by a drift or adit, some form of hoisting system is necessary for slopes or shafts. This chapter will deal with the selection of wire ropes and hoists, two of the most important consider¬ations when designing a hoisting system for an under¬ground mine. WIRE ROPES General A wire rope is designed to transmit forces longitudi¬nally along its axis. Wire rope is used in a variety of mining applications because of its flexibility, high ten¬sile strength, and dependability. Shaft hoisting ropes and principal slope haulage ropes are usually custom-¬built; however, proper rope selection for slushers, car spotters, etc. should not be overlooked. Wire ropes for shafts and slopes, since they represent the life line for the mines, should be of the very highest quality improved plow steel. This quality is necessary to deal with the conditions of loading, winding, vibration, abrasion, and corrosion. Tables I and 2 display the specifications for the typical wire ropes used for mine haulage applications. The 6 x 19-class haulage rope is used for most hoisting where abrasion is not critical. On the other hand, where abrasion is critical, such as a slope application, 6 X 7-class haulage ropes are preferred. For other mining applications, manufactur¬ers' handbooks should be consulted. Selection The selection of a wire rope for a mining situation consists of simply applying appropriate safety factors to a calculated maximum rope pull and comparing the result to the listed breaking strength of the rope under consideration. Table 3 can be used for determin¬ing the minimum factors of safety for wire ropes. To determine the maximum rope pull, the following quantities must be known: the rope weight in pounds (x), the conveyance weight in pounds (y), and the weight in pounds of the load in the conveyance (z). These values are used to calculate the load due to gravity, the load due to conveyance friction, and the load due to rope friction. When these loads are added together, as shown in Eq. 1, the maximum (static) rope pull (RPS) can be derived:

Jan 1, 1986

By Thomas Prietl

The use of gas stirring systems through the furnace bottom is common for anode and holding furnaces in the copper industry The first implementation of a gas stirring COP KIN® system in a Peirce-Smith converter was performed at the New Boliden smelter, Rönnskar, Sweden. In addition to other benefits, a decrease in process time and a decrease of the oxygen content in the blister copper were observed. To determine the effects of the gas stirring system and the process endpoint, an optical production control ?Semtech OPC system? was used. The light emission of the converter flame as an optical process parameter provides qualitative on-line process information, and is also used for endpoint determination of the slag making process, on-line control of iron content in white metal, quality control of slag etc. The results, benefits and risks of using the COP KIN® and OPC system for a Peirce-Smith converter are reported.

Jan 1, 2005

By D. Bienstock

As part of the development of the hot-carbonate scrubbing process by the Bureau of Mines, the corrosion rates of steel in boiling solutions of potassium carbonate saturated with carbon dioxide and hydrogen sulfide were determined, and the effectiveness of various inhibitors was evaluated by Bureau researchers. The highly corrosive solution of carbonate saturated with carbon dioxide can be inhibited with a 0.2-percent concentration of either potassium chromate or sodium metavanadate. Solutions of carbonate saturated with carbon dioxide and hydrogen sulfide are mildly corrosive, 0.01 inch per year. Complete absence of corrosion is obtained with 0.2 percent sodium metavanadate or 0.15 percent vanadium pentoxide. Oxidizing inhibitors such as potassium chromate are destroyed in the alkaline sulfide mixture, N-alkyl trimethylene diamines, at a concentration of 0.1 percent, lower the corrosion rate to about 0.005. Sodium metasilicate, at a concentration of 0.6 percent, completely inhibits the corrosion but may deposit free silica in the system. Commercial cladding materials such as the epoxy coatings also prevent corrosion.

Jan 1, 1962

By George S. Rice

"The emission of hydrocarbon gases from coal beds and contiguous strata causes many accidents in coal—mine workings, the number of fatalities so caused being second only to those due to falls of roof. Gases tend to increase in amount with depth of coal mining, hence the danger of explosion is increased with depth. The pressure of the gas in virgin—coal areas at a distance from mine workings likewise tends to increase with depth from the surface, probably due to corresponding increase in hydraulic head and possibly, when the gas is held in nonporous formations, to greater ground pressure. The rise in gas pressure with depth under usual conditions is shown in wells drilled from the surface and in some coal fields in drill holes into the face of workings; however, under normal conditions of coal formation gas does not issue into workings under high pressure because the coal and adjacent strata have many bedding and joint planes which allow the gas to escape freely at the face of the workings. The rare occurrence of instantaneous outbursts of gas, with violent effects referred to later, constitute the exception.Variations of volume and pressure of fire-damp or methane found in different coal beds by wells at a distance from mine workings, are analogous to variations in volume and pressure of natural gas found in different gas and oil sands, although in general the pressure tends to increase with the depth. Sometimes, however, in tight sands higher in the formation the pressure of gas therein is abnormally high, and on drilling the well deeper gas in the lower strata may be found at lower pressure."

Jun 1, 1934

By Harold W. Lipper

BUREAU OF MINES helium plants produced a. record-breaking 477 million cubic feet of this essential element in 1959. The supply of helium was less than the demand before operations were resumed at the Navajo plant in July and begun Sit a. new plant at Keyes, Okla., in August. Helium was in abundant supply after August, and the informal allocation system which had been in use intermittently since 1955 was discontinued Delivery of 26 new tank cars in August and September increased the total in the tank-car pool to 163. Defense and space agencies and the Atomic Energy Commission continued to use more helium in their operations and research.

Jan 1, 1960

By Luis-Fernando Contreras, Juliano Maran, Richard LeSueur

A risk study was carried out at the Cerrejon coal mine in order to assess the impacts of pit slope failure in terms of safety of personnel and destruction of equipment with economic consequences. Results of the assessment enabled the definition of risk treatment requirements and the identification of key aspects to consider in a risk treatment plan. The approach included the following tasks: (1) Assessment of the total probability of failure (POF) representative of the stability conditions of typical footwall and highwall slopes. For this purpose, stability analyses were carried out to define the Design POF, which accounts for the variability of strength parameters and represents the normal conditions considered for slope design. Strength parameters for highwall slope analysis were derived from borehole data obtained with a geotechnical drilling campaign. The Total POF was estimated through the use of Source Response Diagrams (SRD) in order to incorporate other sources of uncertainty not accounted for, like changes in geometry, variability of rock conditions due to geological or operational factors, changes in groundwater conditions and occurrence of seismic events. (2) Assessment of the consequences of footwall and highwall slope failure on safety of personnel. The assessment was performed through the use of event tree analysis to establish the probability of fatality caused by slope failures, from the Total POF defined in the previous task. This analysis required the evaluation of personal exposure to slope failures. Also, the assessment included benchmarking of acceptability criteria in terms of probability of fatality and the evaluation of options of risk mitigation to comply with these criteria. (3) Assessment of the consequences of footwall and highwall slope failure in terms of economic losses associated with impact on equipment. The analysis included the evaluation of equipment exposure to slope failures, and it was performed through event tree analysis to establish the probability of an economic loss associated to total or partial lost of equipment, from the total POF value defined in the first task. The magnitude of the economic losses was estimated from the costs of damaged equipment, lost production and site restoration. Options of risk mitigation were also examined in terms of economic losses. The risk assessment process applied to the Cerrejón mine showed how the system can be applied to evaluate the consequences of failure in terms of personnel safety and economics and to identify the more adequate risk mitigation options. The system can be an extremely powerful tool in the mine design process and provides the opportunity to rationalize the geotechnical information requirements, once the risk criteria have been defined by management. The main purpose of this paper is to present the process; therefore, the emphasis has been put on the methodology followed rather than on the actual results obtained.

Jan 1, 2006

Common brattice cloths in use in Australian coal mines are compared by permeability measurements. The respective advantages of twill weave and tarpauling* weave cloths are listed, and the improvements to be obtained in the ventilation of a mine by using tarpauling cloths instead of the commonly used twill cloths are stressed. Plastic cloths are widely used overseas and are briefly discussed.INTRODUCTIONThe onset of extensive full-scale mechanization in Australian coal mines during the past few years has increased attention given to the ventilation of working places. Many inadequacies of the present system have been brought to light and not the least of these is connected with the use of brattice cloth, both in directing the flow of air around the face and in acting as a temporary sealing mechanism. A well-constructed line of brattice will only provide fair ventilation for a distance of 100 ft. Beyond this point the volume or air reaching the face falls off rapidly.Some of the shortcomings associated' with the use of brattice cloths are:1. Hurried installation, necessitated by a rapid advance, often results in poor workmanship with, consequently, an excessively high leakage rate.2. High places caused by falls of roof are difficult and time-consuming to seal.3. Curtains, in lines of brattice crossing transport routes, are difficult to maintain.4. Lines of brattice interfere with rock-dusting and clean-up of fine coal.5. Repair and maintenance of brattice consumes much...

Jan 1, 1959

By Silvana Costa

In the last two decades, there have been nearly no new mining towns built in Canada. Governments and mining companies have viewed long distance commuting (LDC), commonly known as fly-in-flyout or fly-in mines, as a way to avoid problems associated with building a new community and providing for its sustainability after mine closure. LDC is also considered more cost-effective than building a mine town. The intensification of the use of LDC in the Canadian mining sector has been quite rapid, particularly in northern regions. However, LDC has implications to employees, their families and communities, which deserve further examination, particularly considering the significant expansion in Northern mining and Aboriginal participation in this sector. This paper presents a review of the major issues in long distance commuting, both from an industry and community perspectives. It is a result of preliminary investigation for a PhD research project that will be pursued by a Bridge Fellow and UBC Mining Sustainability Working Group member, and guided by an interdisciplinary research team at the University of British Columbia (UBC). The Bridge Fellowship Program is research-training program linking the UBC?s Faculties of Medicine, Engineering and Graduate Studies. Its mission is to develop creative evidence-based prevention measures for public, environmental and occupational health problems. The SWG is an interdisciplinary student group based in the UBC Department of Mining Engineering, committed to respond to the complex sustainability-related challenges currently faced by the mining industry. In other to pursue this project, it is paramount that industry and local communities alike participate in the development and clarification of research questions as well as in the research design. It is hoped that this paper will function as an invitation for industrial and community partners for such study. The main themes identified for this research are occupational health and safety of LDC employees, family life impacts and community health impacts of this model of resource development.

May 1, 2004

By Seal. Thom

Large heap leach operations around the world contain significant under-leached metal values that present recovery challenges to operators. The first challenge is to find the location of the highest inventory. High resolution resistivity ? has proven sensitive enough to detect such zones in the interior of heap leach pads to target treatment or re-leaching. Newmont Mining Corp. has adapted the high pressure fracturing technology, used in oil wells to stimulate select zones in heap leach pads to add reagents in 3-D for re-leaching, changing zonal chemistry for improved recovery and heap closure. High Resolution Resistivity ? is able to subsequently monitor injected solution flow and determine directional permeability during Hydro-Jex stimulation. The combination of these technologies has shown strong economic success, for selecting targets in the heaps and monitoring solution application. These technologies are now available to the mining industry for adoption.

Jan 1, 2008

By K. L. Cashdollar, C. K. Man, J. R. Gibbins

Oxyfuel combustion is currently one of the principal technological options being considered for capturing carbon dioxide from pulverised coal power plants. In oxyfuel combustion, coal is burnt in a mixture of recycled flue gases and added oxygen instead of in air. In principle this yields a flue gas containing only carbon dioxide, water vapour and small amounts other impurities. Oxyfuel combustion is superficially similar to combustion in air, but there are inevitable differences. This paper describes ignition tests on pulverised coal suspensions using a suite of coals of different rank and from different countries of origin and over a range of oxygen and coal concentrations of interest for oxyfuel combustion. The ignition tests were carried out using the National Institute for Occupational Safety and Health (NIOSH) 20-litre explosion chamber. The purpose was to determine how easily the various coals ignite and burn in mixtures of O2 and CO2 compared to their combustion in air. The residual char volatile and ash contents for the ignition residues were measured using a thermogravimetric analyser (TGA), allowing Q factors (i.e., enhancement in apparent volatile yield due to higher heating rates and/or heterogeneous reactions) to be determined and compared. An ignition index has been derived from the explosion and char data. This index has been used to rank low volatile coals for ignition propensity in air. The results show that to obtain ignition and combustion comparable to that in air, the oxyfuel O2-CO2 gas mixture must contain over 30% O2. Keywords: CO2 capture, combustion, pyrolysis, oxyfuel.

By P D. Katsabanis

This chapter describes the principles for the derivation of the equations for a detonation wave. The importance of the equation of state for the detonation products is demonstrated and commonly used equations of state are discussed. Furthermore a brief introduction to the TIGER code is presented.

Jan 1, 1991

By Mario Terceros H, Bengt H. Fellenius

"ABSTRACTThe city of Santa Cruz, Bolivia, is historically dominated by houses and three to five storey buildings.The geology in and around the city is such that even very light buildings need to be supported onpiles. The recent increase of the Bolivian economy, notably that of Santa Cruz, has created a demandfor new residential as well as office and industrial buildings, which mostly consist of multi-storey orhigh-rise buildings with significantly larger foundation loads. Foundation piles have become largerand longer, and the load on individual piles is increased. The development has resulted in an increasein the demand for more sophisticated design and construction methods and stricter approach toverifying the quality of the construction processes and results.This paper describes to geology of the Santa Cruz region and how the geotechnical conditions areconsidered in the design and construction of piled foundations. The improvement of past constructionand design techniques, based mostly on bored piles constructed with bentonite slurry, is beingreplaced with new methods of constructing bored piles, e.g. the Full Displacement Pile (FDP) andincorporation of techniques such as enlarging the pile toe, e.g., with the Expander Body. This paperpresents the results of several full-scale tests and discusses the incorporation of the test results indesign and construction.1 GEOLOGY OF THE REGIONSanta Cruz de la Sierra is located in the eastern lowlands and sub-Andean zone of Bolivia, SouthAmerica. The area lies at an elevation of about +400 m and the geology is a Paleozoic (250 millionyears old) sedimentary basin. The soils of interest to civil engineering construction are quaternarywith the dominant minerals being calcite, silica and feldspar. The main agent is the Piray River and itstributaries. Their past meandering over the area has resulted in a sedimentation-erosionsedimentationprocess and a profile dominated by fine to medium sands with intermittent layers ofclay or clayey sand. With increasing distance from the river, the clay-containing layers are thicker.Fig.1.- View of Bolivia with location of Santa Cruz and map of Santa CruzThe upper about 15 to 18 m thick part of the profile consists of normally consolidated layers of clays,silts, sands, in various combination and thickness. Below, the soil is more homogeneous and consistsmostly of sand and gravel. The groundwater table lies typically at a depth of about 6 m in the highestpart of the city and at about 1 to 3 m depth in the lowest part of the city."

Jan 1, 2014

The estimation of the spatial variation of the b-value of the Gutenberg- Richter relationship is important for both the general interpretation of the mechanism of rock mass response and seismic hazard assessment. The interpretation of b-value as a parameter of rock mass response is discussed in this paper. The methods applied to evaluate the spatial variation of b-value and the algorithm for obtaining the magnitude of completeness and b-value for subsets of data are presented with some verification analyses. The algorithms presented enable the automation of a spatial evaluation of b-value.

Jan 1, 2014