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By D. Large, M. H. Davies, B. Driedrichs, U. Matzander

Synthesis report on a project carried out under the EC-funded BRITE-EURAM programme. A prototype high-resolution electromagnetic system, based on the theory of controlled-source magnetotellurics, was developed. The electrical source field is fed into the earth by dipoles at preselected frequencies and a multi-channel receiver measures five electric and three orthogonal magnetic fields. Suitable mapping algorithms and spatial filters are applied to the data and a new technique permits calibration during measurement. The system was field tested over a blind orebody, at 250-550 m depth, in the Aguas Tenidas area of the Iberian Pyrite Belt. Ten lines totalling 12 000 m of profile length were completed in seven days and the orebody was identified. Tests in the Irish Midlands suffered from strong electromagnetic interference of cultural origin

Jun 21, 1905

By G. B. Sonneman

This final report summarizes the work done by The Bendix Corporation, Environmental Science Division, under contract to the Bureau of Mines to design, develop and test two improved systems for remote sampling the air at the working face of a coal mine in conjunction with approved portable methane detectors and machine-mounted methane monitors respectively. The work was started in May 1973 with preliminary design studies and was completed in May 1975. Five portable and two machine-mounted sampling systems were delivered. Contract "add-on" requirements for (1) modification of the machine-mounted system to accommodate a flame safety lamp and (2) a study of sensor response time improvement for the machine-mounted system were also completed.

Jan 1, 1975

By Leonel Lopez

Throughout Mexican history, mining has been an important, traditional activity. Before the "Discovery of America," native miners worked a variety of deposits throughout the country, including Mixtec gold and gem mines in Oaxaca State and Aztec gold, silver and copper from mines in Michoacán. The 500th anniversary of Mining in Mexico after the "Discovery of America" was initiated by the Mexican mining sector on April 15, 1991. As early as 1548, when the Guanajuato mining district was discovered, Mexico had become a leading world producer of precious metals. Since then, Mexican mineral production has developed in cycles, responding to changing technological, economic and political conditions. During the 20th century, Mexican mine output reached its peak in the decades of the 1930s and 1940s, when it was producing about 40% of the world's silver, 15% of its lead, 10% of its zinc, 4% of its copper and 3.5% of its gold. In 1990, by way of contrast, these percentages of world output stood at 13.5% for silver, 4.7% for lead, 4.1% for zinc, 3.2% for copper, and 0.43% for gold. The lowest production levels were recorded during the 1960s and 1970s, when Mexicanization of the industry and increasing state controls weakened mineral economics to a point that mineral exploration budgets were sharply reduced or eliminated, along with the industry's future. Only the noble old mining districts continued to supply production, with occasional eruptions of "bonanzas" and new extensions in established mining districts.

Jan 1, 1994

By Willem Le Roux

1.1 Section 47(1) of the Mine Health and Safety Act, 29 of 1996 (?the MHSA?) establishes a Mine Health and Safety Inspectorate which is administered by the Chief Inspector of Mines. The Mine Health and Safety Inspectorate is part of the Department of Mineral Resources. The Chief Inspector is appointed by the Minister of Mineral Resources (see section 48(1) of the MHSA). 1.2 The Chief Inspector must, amongst other things, ensure that the provisions of the MHSA are complied with and enforced, and that all the duties imposed upon the Chief Inspector and the other Inspectors of Mines in terms of the MHSA and any other law are performed. The Chief Inspector of Mines must appoint Principal Inspectors of Mines and Inspectors of Mines to assist him/her to discharge his/her duties (see section 49(1)(a) and (c) of the MHSA).

Jan 1, 2011

By M. John Brodie

This report reviews the regulatory environment as it pertains to waste rock management and disposal from mining operations, excluding coal and placer gold operations, in the \irate of Alaska. It is based on the EPA's staff position on an effective program to regulate mining waste as presented in the May, 1990 Strawman II document. The unique conditions which occur in pans of the state, including a fragile environment, high seismicity and permafrost, are identified. The special waste management practices which are necessitated by these conditions are delineated. The report provides a detailed outline of the current technologies that are suitable for designing, constructing, operating and closing a waste rock facility to meet environmental protection objectives. Cost implications to the mining industry of potential regulatory actions, such as the degree of groundwater protection, are examined.

Jan 1, 1992

By S. H. Yi, J. R. Kim, Y. S. Lee

The viscosities of CaO-SiO2-Al2O3-MgO-FeO slags were measured under conditions ofCaO/SiO2=1.15–1.6, 10–13 percent Al2O3, 5–10 percent MgO and 5–20 percent FeO. Slag viscosity decreased with increasing FeO content at a fixed basicity (CaO/SiO2) of slag. Slag viscosity at low FeO (<7.5 percent FeO) exhibited a minimum value by increasing MgO content in slag. Viscosity decreased with increasing slag basicity up to 1.3 while it increased as slag basicity increased from 1.3 to 1.5. Thus, it was proposed that the driving force for the decreases of slag viscosity would be an increase in depolymerization of silicate network at C/S=1.3, while the viscous behaviour at C/S>1.3 would be increased with increasing the chemical potential of primary solid phase e.g. dicalcium silicate. A thermodynamic approach for the activity of primary solid phase in molten slags resulted in a reasonable relationship between viscosity and slag components. Therefore, it was confirmed that slag viscosity in basic slags system (C/S>1.3) could be determined by the chemical potential of dicalcium silicate. Keywords: viscosity, basicity, bosh slag, blast furnace, slag structure, FT-IR

Jan 1, 2004

By Henning E. Soderberg, Robert Brien, O&apos

Coal may be the answer to US energy problems, but it also has its drawbacks. If it is crushed, screened, dumped, or moved, the environmental engineer is faced with a dust problem. To control coal dust, at both minimum initial cost and reasonable operating cost, demands a working knowledge of dust control equipment design, as well as the coal handling operation. Here are some guidelines to reduce air volume requirements and cut overall system costs.

Jan 10, 1981

By Jacques J. Eksteen

Metallurgical accounting around toll treatment smelters pose a number of challenges. This paper reviews the requirements for good sampling practice, and how conflicting requirements for good furnace operation and design often makes reliable closure of the metallurgical balance tenuous at best. Typical physical causes of variance and bias will be identified. The propagation of error (in the form of variance) will be discussed for a copper smelter.

Jan 1, 2006

By John Rudolf

Metropolitan Washington Airport Authority is currently undertaking the first Phase of Metro?s Extension to Northern Virginia. A wide range of tunnel options was considered for the Tysons Corner segment that involves about 20,000 feet of track and four stations. After consideration of many options that involved EPBM single track tunnels, NATM tunnels and large bore tunnel concepts for the entire Tysons alignment, the design now being progressed into construction involves two 520 meter (1,700 feet) long soft ground NATM tunnels with several hundred feet of cut-and-cover construction. The paper discusses the process that led to selection of the short NATM tunnels as the most feasible of the options considered for Tysons.

Jan 1, 2008

By Alfred V. de Forest

WE are now assembled in this hall for the eighteenth lecture in honor of the memory of our greatest American metallurgist, Henry Marion Howe. Many of his most intimate contemporaries, led, as was fitting, by Professor Sauveur, have described his vital accomplishments in three fields: as a leader in technical industrial development; in theoretical research; and finally as a teacher and source of inspiration for nearly two generations of students. In 1914 Professor Howe had retired from active teaching, but maintained his laboratory at Columbia University under the care of Arthur G. Levy, with whom he published many of the papers that later were incorporated into his last book, "The Metallography of Steel and Cast Iron." My position at the time was that of personal assistant to Professor Campbell-no pay, no duties, but the great privilege of preparing specimens, taking pictures and attending to some of the current consulting work. Whenever possible, I visited Howe&apos;s laboratory to chat with Levy and gather ideas about the wonderful field of metallography-in which I was a rank amateur, rescued by the quiet enthusiasm of Donald Smith of Princeton from an instructorship in civil engineering. Levy let me act as a fly on the wall during the Professor&apos;s occasional visits. Busy as he was, Professor Howe took the time and trouble to encourage my interest, as he had done for hundreds of others. He told me how he went about gathering his own information speculating as to causes, considering experiments, and verifying his conclusions. I ventured to mention some tests I had run on the irregular stretching of wires of different metals. He read the small volume I had prepared of ill-assorted facts and fancies and remarked: "Nobody cares for your theories or the history of your tests. Describe what you found as briefly as possible and perhaps I can help you to publish." Curiously enough, among my discards were some autographically recorded load-versus-electrical-resistance measurements. Taken with inadequate knowledge and equipment, these curves did not reproduce consistently, but if the relationship between strain and resistance had then been explored, the latest type of strain gauge might have been in useful service for the past 25 years. Professor Howe was a gifted teacher, perhaps because he was primarily an ardent and assiduous student. His own eagerness to learn and his willingness to revise and extend his opinions constantly encouraged those of his environment to be diligent and painstaking in the pursuit of knowledge. In honoring his memory, I also wish to bring to mind the kindly, humorous and quiet Levy, and join his name again, as it was for too brief a space in the past, with that of many-sided Henry Marion Howe. FACTORS OF IMPACT STRENGTH The subject chosen for the Howe Memorial Lecture by Dr. Gillett last year

Jan 1, 1941

By James Scott

Outline Deposit Overview and Brief History ?Geologic Setting ?Local Geology ?Petrography ?Geochemistry ?Mineralization ?Geochronology ?Conclusions Deposit Overview ?Porphyry Cu-Mo-Au ?Discovered 1957 (BIK Syndicate) ?Various programs, most significant: ?Hecla(1970s) ?Teck(Late 1970s Early 1980s) ?Copper Fox Metals (2005 -Ongoing ?optioned from TeckComincoin 2002) ?Measured and Indicated Resources: ?847Mt grading: ?0.292% Cu ?0.019% Mo ?0.202g/t Au ?1.796g/t Ag ?Total ~ 0.485 % Cu Eq.

May 1, 2006

By Yavuz Ali Topkaya

Rare earth ferrosilicide is a versatile alloy mainly used to control the detrimental effects of sulfur in steel and to modify graphite structures in cast iron. The aim of this study was to determine the optimum conditions to make rare earth ferrosilicon alloy using a preconcentrate produced from a bastnasite type of ore present in the Beylikahir-Eskisehir region of Turkey. This concentrate contained 23.5%REO, 41.37% CaF2, 10.69% BaSO4, 8.50% CaCO3, 4.18%Fe2O3, 2.83% Al2O3, 2.74% SiO2, 1.20% P2O5 and small amount of other oxides. The initial metallothermic reduction of this concentrate using ferrosilicon and aluminum in a graphite crucible placed in a muffle furnace gave very low recoveries due to the difficulties encountered in adjusting the slag composition, temperature and amount of additives. Therefore, two batches of rare earth oxide concentrate containing 61.1% and 81.7% cerium oxide, respectively, that were procured from a Turkish glass producer, were used to optimize with respect to temperature, duration, slag-making additives and amount of reducers. In these experiments, smelting and reduction was done in an induction furnace with graphite crucible, and, ferrosilicon and aluminum were added after melting the charge. As a result, there was no difficulty in obtaining a rare earth ferrosilicon alloy containing 35-55% RE, 5-25% Fe and 20-40% Si, with about 80% metal recovery. When the optimum conditions were applied to the preconcentrate, alloys of similar compositions were obtained with 70-80% recovery. Experiments were also done with mixtures of preconcentrate and rich concentrate, and, recoveries as high as 95% were obtained. Only in this case, to increase the recovery, mixtures had to be charged to the empty graphite crucible after heating the crucible to the required temperature.

Jan 1, 2006

By John Rajala

The Otjikoto Gold Mine in the Republic of Namibia is located approximately 300 kilometers north of the capital city of Windhoek. The project features surface mining with a modern gravity/carbon-in-pulp mill for ore treatment and recovery of gold. Initial mill design capacity was 2.5 million tonne per annum but then expanded after 9 months of operation to 3.1 million tonne per annum. The technical steps to establish the Otjikoto mill design from process selection in the due diligence stage, through flowsheet development in the feasibility study followed by detailed engineering design are reviewed in this paper along with mill performance during start-up and in 2019.

Oct 30, 2020

By R. D. Saltsman

This report is in fulfillment of Contract No. H023001.5 awarded to Bituminous Coal Research, Inc., on November 15, 1972. The scope of the work under this contract was to perform a two-phase survey for the purpose of determining the status of work in the following specific areas of industry needs under the Technology Transfer Program and to increase industry&apos;s awareness of research efforts under the Federal Coal Mine Health and Safety Act of 1969 6f (P.L. 91-173): 1. Research and development of respirable dust sampling instruments which will more accurately collect the respirable Cuss as defined by the Federal Coal Mine Health and Safety Act of 1969. 2. Development of a better means of control of respirable dust and float dust.

Jan 1, 1973

By Donald R. Corson

The effects of adding varying amounts of type I portland cement to hydraulic backfill are described. Six different fill materials, each with three cement contents, were tested to determine which fill properties have the most significant effect on cemented strength. Two strength prediction equations, based on the physical and mineralogical properties of the fills, were formulated, and these accounted for 96 and 99 percent of the variability of the data. Results of both unconfined compression and triaxial tests of cemented fills are given, and the effects of moist curing and fill densification on the 7-day strength are discussed. Permeability test data are given, and the decreased permeability due to cement content and curing time is shown graphically. A discussion of the limited evaluation of other potential stabilization additives (expansive cement, fly ash, sodium silicate, gypsum, and asphalt) is included in an appendix.

Jan 1, 1970

By Lisa A. McDonald

The environmental compliance process affects all aspects of hardrock-mining operations, from exploration through post-closure. The primary components of the environmental compliance process are requirements under the National Environmental Protection Act of 1969 (NEPA) and the permitting requirements associated with various other federal, state and local laws. This study considers the Greens Creek Mine and the development of two other projects (Alaska-Juneau & Kensington). These mines were used as the foundation for a case study of the impacts of the environmental compliance process on hardrock-mining activity in Southeast Alaska. The case study presents the institutional and legal requirements, followed by a discussion of the impact of this process on the production and timing of the three mines. The results of this preliminary study reveal some interesting findings, some expected and others unexpected, regarding the impact of the permitting process on the exploration, development and (proposed) operation of the three mining projects in the Juneau area. Determining the cost of compliance with these requirements is an important step in evaluating the appropriate course of action to protecting the environment while providing the necessary raw materials needed for society. This preliminary study highlights the initial starting point for such an analysis.

Jan 1, 1992

By P. S. Pashkovsky, S. N. Smolanov

The essence of the method consists in creation of drop of opposite sign at the isolating stoppings, by which air losses through the accident district change direction of their motion. The period of reversal is selected in that way so that air may not find itself in the zone of burning. The method of fighting the fire considered was repeatedly used in the coal mines of the Ukraine. The theoretical basis of efficiency and two examples of use of this method by fighting the underground fires are adduced in the paper.

Jan 1, 2003

By Tim O’Neil

If you build a big truck, build a big tire to match it. Let that haulage synergy aid the economics, productivity and lessened maintenance for the unit. Now, Cater-pillar and Michelin have done just that. Discussions began in 1996. Caterpillar was making plans for its 797 ultra-class haul truck. The development team realized the need for a tire that could withstand extreme loads. The 797 would weigh 558 t (615 st) and be capable of 64 km/h (40 mph) speeds. So Caterpillar approached Michelin. The two companies realized the benefits of jointly developing a tire for the 797.

Jan 1, 2002

By M Watson, A V. Engelbrecht, E Murray-Hayden

Whereas mine reconciliation is a well-established month-end process for most modern mining operations, the resource sector has yet to endorse uniform reporting factors against which model accuracy and metal recovery can be formally assessed. Logically, any comprehensive reconciliation framework should facilitate comparison between period reserve, mine and mill and production figures. Historically, Parker’s F Series ratios (Parker, 2012) are often used in some form by mine operators, although they are rarely shared externally, as formal definitions have yet to be accepted. This paper presents a structural extension to the reconciliation process, wherein resource ratios (R Series factors) are used to quantify the long-term impact of the information effect, together with dilution and ore loss. A case study from the El Limón Guajes (ELG) Mine Complex in Mexico is used to demonstrate how an R Factor Series can be implemented to facilitate operation optimisation, over and above conventional F Series reconciliation treatments. This approach is applicable to any mining operation.

Mar 22, 2022

By P. Mousset-Jones, G. Danko

Variations of the temperature and steam/moisture content of the air with distance and time are modelled for a single airway. The input for the simulation is an air temperature that varies with time, together with the moisture/steam content that results, for example, from a fire with a given distribution of heat and of fume concentrations at the beginning of the airway. The transport of heat and moisture to the surface of the wallrock is assumed to be simultaneous. Such multiphase convection may result in evaporation from the moist wall close to the fire and recondensation downstream. The modelling of this non-linear effect is a unique feature of the new simulation. A new analytical solution is used to calculate the conduction of transient heat within the rock mantle, which, in the event of a fire, is typically a short-term process. This allows for an arbitrary variation of surface temperature with time - unlike that permitted by the age function solution, which is limited to stepped temperature changes. An iterative numerical scheme that has recently been developed to simulate mine climate is used to calculate the coupled transient heat conduction and multiphase surface heat transport in successive length increments along the airway. To demonstrate the simulation procedure a numerical example is presented in which a fire with a given distribution of heat and fume concentrations with time is located at the beginning of an airway

May 1, 1991