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By Joseph Renk, David Akers, Glenn Shirey

Each year, US coal cleaning plants landfill or impound millions of tons of high-quality, fine-sized coal. This coal is not only difficult and expensive to capture during cleaning, but, if captured, can pose serious materials handling problems. The GranuFlow. Technology was developed and patented by the U.S. Department of Energy (DOE) to address these problems. GranuFlow involves the addition of a coal binding agent such as an asphalt or heavy oil emulsion to coal to reduce moisture, dusting, and freezing and to improve the flow properties of the coal in bins and chutes (1, 2, and 3). When the emulsion is added before mechanical dewatering, the binding agent causes the formation of fine-sized coal agglomerates that dewater better than untreated coal. In addition, the binding agent increases the capture of ultra-fine coal in screen-bowl centrifuges. Previous work by DOE has also demonstrated that such treatment results in a significant reduction in dustiness and a reduced potential to freeze. To address concerns about the handling and combustion characteristics of GranuFlow treated coal, DOE performed a pilot-scale pulverization and combustion test (4). No problems were encountered during pulverization or combustion, and use of this fuel in a p.c. boiler was found to be feasible from a technical perspective. CQ Inc. has an exclusive license from DOE to market this technology and is currently performing a series of commercial demonstrations to determine if GranuFlow is both technically and economically viable.

Jan 1, 2005

By Adrian Fleming

Adrian Fleming is Executive Vice President of Exploration for Golden Star Resources Ltd., Denver. Adrian is an Australian who graduated in 1973 with an honors degree in geology from Newcastle University, New South Wales. His extensive international experience has spanned exploration, project development, and operations for both large and small companies in Australasia, Southeast Asia, North and South America, and Africa. Adrian has been with the Golden Star group of companies for four years and he is responsible for all exploration activity. ABSTRACT Golden Star acquired the rights to the Omai prospect in 1985 at a time when the country of Guyana was out of favor with the exploration fraternity. Subsequently in the late 1980s and early 1990s, Golden Star acquired exploration properties in Suriname and French Guiana well ahead of its competitors. Golden Star's strategy entailed identifying windows of opportunity and aggressively pursuing them. We also recognized that the Guiana Shield hosted a significant area of highly prospective greenstones which were comparable in metallogenic potential to similar terrains in eastern Canada, western Australia and west Africa. The geological skills Golden Star developed and the exploration techniques employed to explore deeply weathered rocks are described. The paper highlights the key elements of Golden Star's strategy and illustrates how some of the milestones reached by the company led Golden Star to establish an enviable portfolio of gold and diamond properties in the Guiana Shield.

Jan 1, 1998

By J. C. Edwards, C. C. Hwang

A computational fluid dynamics (CFD) program was applied to fire spread along combustibles in a ventilated mine entry. The rate of flame spread was evaluated for the ribs and roof of a coal mine entry; timber sets; and a conveyor belt. The CFD program models char forming materials with temperature dependent thermal properties. The program solves three dimensional time dependent flow equations with a mixture fraction model for the gas phase reactions. Radiant heat exchange is evaluated for non-scattering gas. The CFD program predicted a flame spread rate of 0.0145 m / s for an actual coal mine fire in which the estimated flame spread rate was 0.0086 m / s. This overestimated flame spread rate was a possible consequence of the presence of inert materials in the mine entry’s roof and ribs. CFD fire spread rate predictions of 0.043 m / s and 0.73 m / s bounded the measured value of 0.27 m / s for fire spread along Douglas Fir timber sets in a tunnel.

Jan 1, 2006

By Tadashi Nishida

Subsidence due to mining caused various kinds of damage to the surface structures, and actually great deal of mining damage becomes the severe social problem at some time in many coal fields, but the most of mining damage was restored at present. Recently, the effect of old coal working on the deformation of newly constructed structures has become into question, because it was obliged to plan many engineering structures in old mining areas for the shortage of adequate construction sites and the difficulty of getting location. That is, building, dams, bridges for railroads and highway, power plants, tunnels, storage tanks and so, have to be built on the ground which has old coal working.

Jan 1, 1982

By T. Reed Scollon

Before we can attempt to answer the question of what can be expected from coal research, let us examine why research is done in other fields and what others expect for the money they spend on research and development. Up to 1900 almost all organized research was carried out at universities. Most of the support came from the university, and by present standards the amount of research was extremely small. The motivation for university research was basically discovery of new phenomena, with the objective of advancing knowledge. Side by, side with this organized effort was that of individual inventors who were primarily responsible for applying this new-found knowledge to useful purposes. During this period inventors were rarely supported by anyone, and experimentation was carried out either in their spare time or at the expense of earning a living. Men like Edison, I believe, were the first to demonstrate on a large scale that one could systematically apply newly discovered scientific principles to inventions that would serve useful purposes and would return a profit to those engaged in the effort. The tremendous expansion in research therefore began with the realization and demonstration that the scientific discovered could be applied in such a way as to return a' handsome profit to those who invested in it. The motivation of many of the research personnel however, remained the satisfaction associated with new discoveries, The money to support their efforts came from those interested in a return on their investments. Since the First World War and a rapidly accelerating rate since the Second World War another important motive for supporting research has appeared--the needs associated with national defense; this type of research has been supported almost exclusively by the Government.

Jan 1, 1959

By C. Geier

Previous mine incidents show weaknesses in mine rescue preparedness from poor training in decision making, leadership and incident command center (ICC) protocols. Computer simulations offer a larger range of training opportunities for mine rescue teams focusing on exploration and communications. The mine rescue simulator developed by the Colorado School of Mines and Rite Solutions Inc. utilizes four computers for the instructor and team, with the instructor monitoring the team?s progress. As the team explores, it relays information back to the Fresh Air Base, which then reports to the ICC. This forces a three-step communication procedure, enhancing the team?s overall communication skills and developing ICC protocols. The simulator is decision-based, demanding team decisions be made quickly. Upon completion, teams commented positively. Generally, participants said that the simulator is useful for learning how to communicate and make decisions during mine rescue emergencies. This mine rescue simulator improves team training, providing effective communications practice with an easy setup and no production interruption.

Feb 1, 2014

By Raoul Fernandez, Bernard Catalano, Guillaume Roux

The Thaumasia Joint-Venture, composed of Bouygues Travaux Publics, Soletanche- Bachy and Bessac, completed the construction of the underground section of line 2 of the Nice tramway, which comprised a 3.2 km twin track tunnel and four underground stations, in a particularly complex urban and geotechnical context. The density of the surface structures, as well as the presence of many historic buildings on its route made the construction of the tunnel even more sensitive, with a settlement threshold of Half an Inch. The joint venture faced a complex subsoil, varying from one extreme to another from highly plastic clay layers to fibrous peat and to cobbles with very high permeability, with artesian ground water, and with unforeseen anthropogenic obstacles in the tunnel section Due to the diversity of the problems encountered and their variability over short distances, the construction of the underground section of the Nice tramway, in its very sensitive urban context, undeniably constituted an unprecedented challenge.

Jun 13, 2023

By M. Niec

Lignite deposits in Poland occur within clastic Tertiary series at the depth suitable for opencast mining. Aboundant aquifers with the good quality waters that should be protected against contamination or depletion often accompany them. Landscape and underground water protection are the main regional environ-mental factors that limit the possibility of exploration and mining; presented on map of lignite bearing series distribution allow to delimit areas "free" for exploration and mining and areas where some limitations can be met up to no admittance of any industrial activity.

Jan 1, 1994

By M. R. Smith

Barrick Goldstrike Inc.'s Betze/Post Open Pit is located at the north end of the Carlin Trend, in Eureka County, Nevada, U.S.A. (see location Map, Figure 1). About ten open pit gold mines exist on the trend, which strikes northwesterly, through the north end of Eureka County and into Elko County. The final Betze/Post Pit configuration is shown in Figure 2, Pit Configuration. The final pit will be about 2450m long by 1550m wide, elongate in a west-northwesterly direction. The pit straddles the Barrick/Newmont property boundary. The highest elevation of the pit perimeter is 1800m at the south wall, with the east end pit bottom elevation at 1200m.

Jan 1, 1993

By Clyde N. Garman

The Homestake-New Mexico Partners consist of Homestake Mining Company of Lead, South Dakota; Rio de Ore Uranium Mines, Inc; United Western Minerals Company; White, Weld and Company; J.H. Whitney; San Jacinto Petroleum Corporation; and Clyde Osborn, Homestake Mining Company is the general partner, the others are limited partners. The Rio de Ore Uranium Mines, Inc. has. a mine in the Ambrosia Lake area; this was the first mine to go into production in this area. The United Western Minerals Company also has a mine in the Ambrosia Lake which is operated as a "farm out" from the San Jacinto Petroleum Corporation. These mines are the principal sources of ore for the mill. This group was the first to obtain a contract with AEC to make uranium concentrate from Ambrosia Lake ores and the first to have a mill in operation specifically for these ores. With Clyde Osborn as the sparkplug and co-ordinator holding the ore suppliers of, this group together, a contract with AEC was agreed on as to its essential points by mid-summer, 1956, At that time, there was no general partner and no financing, so me formal contract could be signed. By December, 1956 when the contract was signed and the present partnership officially formed, much of the basic engineering was done and purchasing of main elements of the mill waited on the formalizing of agreements, at the specifications and sizes agreed on previously. Ground for the mill was broken in April, 1957. The sampling plant went into operation in October and ore was first fed to the ball mills on February 5, 1958, ten months after construction actually started. Filling of the circuit with sodium carbonate bicarbonate solution had begun a week before that.

Jan 1, 1959

By S. C. Schmelter

The destabilizing effect of water pressure on rock mass stability is examined quantitatively by the finite element method. A coupled code that accounts for the simultaneous effects of rock mass deformation and transient fluid flow is used for this purpose. The traditional soil mechanics assumption of an incompressible fluid is shown to be untenable for the analysis of porous, fractured rock slopes. A Mandel-Cryer effect, a transitory but elevated and potentially destabilizing water pressure following a cut, was not observed.

Jan 1, 1997

By Matthias Neuenschwander, Andreas Theiler, Patrick Steinle, John Singer, Martin Vogel, Diego Martini, Ömer Ündül, Markus Weh

"Quartz Dust is a major health hazard in underground works, wherever the ground contains quartz and depending on the chosen method of excavation. A research project initiated by the Swiss Tunnelling Society and realized by the Swiss Federal Institut of Technology, Zurich, established a correlation between the potential of quartz dust generation during excavation and well known geotechnical characteristics – the Cerchar Abrasivity Index CAI and the Uniaxial Compressive Strength UCS - of ten typical Swiss rocks. The results are at the center of a new guideline by the Swiss Society of Engineers and Architects on the requirements for early project stages regarding ventilation and logistics in function of the quartz dust related risk of the expected ground type of the project. The approach presented could be applied worldwide, contributing to more effective health protection as well as to better cost stability in underground works. CONTEXT Respirable quartz dust (aerodynamic diameter of particles < 10 micron) is universally recognized as a major workplace health hazard. Chronic bronchitis, silicosis and lung cancer can be caused by excessive exposure to quartz dust, as has been proved by many medical studies. Therefore, the legislations of many nations specify a maximum workplace concentration (Maximale Arbeitsplatzkonzentration MAK, Occupational Exposure Level OEL). In Switzerland, for example, the Threshold Limit Value TLV for respirable Quartz or Crystalline Silica imposed by the Federal Committee on Exposure Levels (Grenzwertkommission) is 0.15mg/m3 air. Some nations refrain from establishing a OEL because of the carcinogenic nature of quartz."

Jan 1, 2016

By Clement K. Chase

Although flotation is the generally accepted process employed to recover gold and silver as well as copper, lead, and zinc from primary sulfide ores, the metallurgical requirements for the treatment of massive sulfide ore deposits differ markedly in many respects from those employed for the more common disseminated porphyry deposits. In Arizona, some properties classified as other then massive sulfide deposits because of mining and geological characteristics have produced mill-feeds similar to those from massive deposits. Several such occurrences are noted. The process requirements for massive sulfide deposits and unique mill-design implications are discussed in the perspective of world-wide economic considerations and the individual regional metallurgical and economic constraints in the United States.

Jan 1, 1986

By G. S. Adisoma, J. J. K. Daemen, R. O. Roko

A common assumption in determining the shear strength of a rock joint using a direct shear test is that the surfaces undergoing relative shear are in complete contact. Furthermore, the limiting displacement associated with the residual strength values is obtained based on engineering judgement through visual inspection of shear force versus displacement curves. This study proposes a systematic way of determining the residual shear strength of rock joints by evaluating the limiting displacement leading to a minimum cohesive strength value and taking the true area of contact into account. The results of the study indicate that there is a limiting displacement associated with the residual shear strength, and some rocks may have an inherent interface residual cohesive strength different from zero. When the cohesion is different from zero, the residual shear strength is likely to be underestimated if the true area of contact is not considered. In the case where zero calculated cohesion is obtained, the area of contact has no bearing on the shear strength equation because the frictional force depends only on the normal load.

Jan 1, 1986

By R. W. Brann, R. C. Freas

Franklin Industrial Minerals operates several mines/quarries, including two room and pillar underground mines. Both of these mines are operated as multiple level room and pillar including heading and bench operations on one or both of the levels. This paper focuses on Franklin’s Crab Orchard, Tennessee mine, which produces both high purity chemical grade limestone and crushed stone for construction applications. The high purity chemical specifications for the chemical grade limestone and filler/extender applications are inconsistent with the non-chemical rock being produced to supply the crushed stone market. As a consequence Franklin has developed a unique mine plan and operation to maintain both product balance and a safe and stable working environment.

Jan 1, 2003

By Y. Zeng

Experiments were performed under batchwise wet grinding conditions with dolomite mineral. The vibration signal was received by an accelerometer and transmitted to a mini-processor. The signal was first stored on a digital tape recorder (OAT) in voltage format during the grinding tests. The original signal was then re-sampled and converted into data format for IBM or compatible personal computer by a digital oscilloscope. The root-mean-square (RMS) and power spectrum was estimated on the time-domain vibration signal. A partial correlation analysis was applied to the frequency-domain signal to detect the non-zero correlation between the frequency bands and the operating parameters. A multiple stepwise regression was used to locate the key frequency bands for describing a particular operating parameter. After vibration analysis, the operating parameters in grinding, for example, the mill speed, the powder filling, the pulp density, the pulp temperature and the particle size were found to be strongly correlated with a few frequency bands. The grinding process could therefore be monitored using the vibration signal.

Jan 1, 1992

By C. Braux

The aim of this study was to develop an integrated approach to enable identification of areas favourable for the presence of massive sulphide deposits in a given region (Las Herrerias, Spain). It is based on geochemical soil exploration, geophysical surveying (ground gravimetry), detailed geological mapping and a knowledge of the deposits of the South Iberian Massive Sulphide Belt. The multi-dataset approach consists, in the first instance, in standardizing and combining all the geochemical data with reference to their geological setting. Next, the "heavy" anomalies are extracted from the gravimetric survey, regardless of the surrounding context (heavy or light). The results from these two stages are then crossed, so that areas where heavy anomalies are associated with geochemical anomalies can be identified and classified. Crossing the geochemical and geophysical data enables a much tighter selection of anomalies than does the manual superposition of data provided by each method (geology, geophysics, geochemistry).

Jan 1, 1994

By W. W. Hartley

Following a Major underground coal mine incident there followed a review of the role of mines rescue ? the Queensland Mines Rescue Brigade. It wasn?t until 2002 that the real change started to happen. The issue of geographical distance was addressed by mines rescue sub stations being located on the mines sites with parent rescue stations in a central location. The funding was by means of a levy on the mining industry with legislative standards and performance included. The previous Rescue Brigades were not well organised (central districts) and the application of recognised quality management practices within local management was lacking. The structure was based on other nations models and miners managing miners was an issue for the organisation. The reform was some what painful and the QMRS organisation will still evolve with continuous improvement. Queensland has the National Champion mines rescue team for the eighth year. QMRS is participating at the level in the industry of influencing emergency systems and training senior mine management in ?Emergency Mine Management? coaching the industry in emergency response systems. We have come a long way. We have had some success and there is always the challenge of setting the standards, those we should aspire to and the courage to influence the industry to higher goals of a safer future.

Jan 1, 2010

By E. Turner

This is the 3rd Paper in a series by this author, the first two being published at the two previous International Conferences. Since the Aachen Conference, Rio Tinto has carried out an extensive benchmarking exercise to see how we are positioned with respect to other leading companies (in our sector and other sectors of major economic importance). We need to be sure that Rio Tinto is at the forefront of best practises in Sustainable Development (SD) and is using the most effective tools and methods. This paper will present key findings from this work. Rio Tinto Minerals, working as representatives of IMA-Europe was a leading contributor to the European Commission DG Enterprise Voluntary Reporting Scheme for SD Indicators in the Non-Energy Extractive Industry. In Rio Tinto Minerals we have been using these SDIs in the management of our business and the paper will report on how they contribute to the management of our business and the paper will report on how they contribute to business value in: deepening customer relationships, eco-efficiency of operations, land use planning and permitting for new and expanding facilities, community relations, policy engagement with government authorities and strengthening the bond between the company and employees. We continue to support the Voluntary SDI Reporting Scheme, considering it to be important in the expanding EU and as a model for other regions globally. For example we have ore suppliers in developing countries and we use these SDIs in assisting them to better their performance, for we have an obligation to use our influence for continuous improvement. The paper will describe this work. Over the last 12 months our company has created a new Industrial Minerals unit called Rio Tinto Minerals which brings together all the borates, talc and salt operations, R&D, marketing, sales and customer care worldwide. The paper will present also the new Sustainability Policy of Rio Tinto Minerals.

Jan 1, 2007

By Duluth Engineers' Club, Engineers' Club of Northern Minnesota

"During the last ten years great strides have been made, on the Mesabi Range, in the practice of beneficiating low grade iron ore material. By .beneficiation is meant all methods of removing impurities, and raising the iron content to a point where it can be sold in open market, the principal impurities being silica and moisture. The • general processes to which low grade iron ores are amenable are as follows:1. Thermal(a) Drying ; removes hydroscopic or atmospheric moisture. .(b) Calcining; removes carbon dioxide from iron carbonate, molecular water from hydrated hematites, and atmospheric moisture.Roasting; removes sulphur, carbon dioxide, molecular water and atmospheric moisture.Agglomeration; primarily for the purpose of preparing finely divided material for blast furnace; briquetting and sintering.2. MechanicalScreen sizing; removes rock and sand.Classification; removes sand by means of currents of water of varying velocities.Log washing; removes fine sand.Jigging; removes larger particles of impurities than is possible by log washing. Certain types of jigs remove fine sand.Reciprocating tables; recover fine iron particles from sand discarded by above processes.Magnetic separation; applicable to the commercial separation of the magnetic oxide of iron from gangue material. From a scientific standpoint it is possible to separate certain hematites and limonites from their gangue:(g) Miscellaneous processes; comprise dry concentration, electro-static separation and other processes."

Jan 1, 1920