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By Takuji Yamamoto

High-speed TBM excavation requires rapid ground assessment ahead of excavation, particularly in complex grounds. The Tunnel Reflector Tracing technology (TRT) developed by authors, uses seismic reflections to produce volumetric images of ground anomalies. To further minimize interruption in the TBM excavation the authors modified surveying technique switching from cable (wired) to radio (wireless) data acquisition system. This paper presents the outline of the Wireless TRT system, and compares the results for the wired and the wireless surveys. The comparison shows that the wireless system offers high precision data, is more efficient and economical and significantly less intrusive in tunneling operations.

By S. Mundike

A scraper-based block cave method has been successfully applied to extract the Lower orebody at Nchanga since the 1950s. Since inception, scraper drifts and service ways have been supported using steel arch sets fabricated to a specific design from high strength manganese steel To reduce costs and to improve productivity, trials commenced in 2002 using fibre reinforced shotcrete as an alternative support method. One of the areas, the 2420 8E 1C trial drift, was subjected to abutment loading for several months prior to undercutting and cave mining. Shotcrete installed exhibited minor cracking shortly after application but very little deterioration thereafter. Following the success of the trial, the application of fibre-reinforced shotcrete was extended to other drifts. This paper describes the application of fibre-reinforced shotcreteat Nchanga and outlines design and quality assurance methods employed.

Jan 1, 2005

By Alla D. Mah

The heat of formation of scandium sesquioxide (Sc203) has not been measured previously, and existing values for gallium sesquioxide (Ga203) are subject to large uncertainties. As a consequence, thermodynamic calculations involving these oxides hare lacked scientific exactness. This paper reports newly determined values of the heats of formation of gallium and scandium sesquioxides at 298.15° K., by combustion calorimetry. The corresponding free energies of formation are derived from heat and entropy data.

Jan 1, 1962

Copper Recovery from Printed Circuit Board by Carbonisation

Sep 13, 2010

By T. E. Pogue

This paper traces the co-operative initiative undertaken by South Africa?s gold mining companies through the Chamber of Mines Research Organization (COMRO) in development of hydraulic technologies. After a brief description of the structure of these technologies? development under COMRO?s stewardship, the paper turns to an overview of the structure of innovation within which these hydraulic technologies were developed. A central focus of this paper is systematic review on whether similar technologies are likely to emerge in the present system of innovation and the role played by innovation policy.

Jan 1, 2006

By P M. Bradbury

The nature of aggressive process chemical requirements typically in the Platinum Refinery Industries, lend themselves to the use of Polymer Composite Glass Reinforced plastics for pipework and other associated equipment in these types of Plants. This paper discusses the basic characteristics of a Polymer Composite glass reinforced piping system and gives sample examples of applications in current present day use.

Jan 1, 2006

The recovery by flotation of some complex uranium minerals such as brannerite and davidite is described. Anionic reagents used for flotation of iron and titanium oxides' are suitable. If care is taken, to emulsify the reagents the slime fractions may be satisfactorilytreated.INTRODUCTIONUranium ores are usually treated by direct leaching with acid or alkali according to the nature of the gangue materials. Concentration of the uranium minerals prior to leaching is not commonly practised because of the earthy nature of most uranium minerals and the difficult mineral dressing problem they pose. Some of the harder complex oxides such as davidite and brannerite are amenable to flotation. This is fortunate since they usually require an expensive, strong acid treat~ent to dissolve the uranium. Flotation tests were commenced in 1949 by officers of the South Australian Department of Mines stationed at Adelaide, first in the School of Mines, then in the University of Adelaide and finally in Departmental mineral dressing laboratories at Thebarton. Separation of daviditefrom Radium Hill and Mount Victoria ores, brannerite from Crocker's Well ore, and secondary uranium minerals from Myponga ore was attempted.The development of the flotation reagents to separate the oxides from silica and the silicates is first described, then some of the results obtained are presented as tables.DEVELOPMENT OF FLOTATION REAGENTSThe davidite at Radium Hill is associated with iron and titanium oxides, qu;a,rtz and biotite as replacement deposits in shears. The davidite, rutile,' ilmenite and hematite usually occur in segregations from nut size to masses of several pounds. They are associated as a complexity of...

Jan 1, 1955

By J. N. Van der Merwe

The data base of failed coal pillars in South Africa was analysed with regard to the time of failure in an effort to develop a method to predict how long after their formation coal pillars will fail. It was found that meaningful results could only be obtained by splitting the data base up into groups that displayed similar behaviour. It was postulated, based on observation and experience, that coal pillars fail by a process of progressive weakening progressing into the pillar from the edges. Minimum pillar dimensions to ensure failure were calculated?these were the dimensions that corresponded to a minimum ?real? factor of safety. From the scaling distance required to reach the minimum safety factor, rates of scaling for the failed pillars were calculated based on the observed real lives of the pillars. It was found that the rates of scaling were unique for different mining areas and that they correlated directly with mining height and inversely with time. Using the derived scaling rates, the predicted pillar lives were back calculated for the pillars in the data base of failed pillars. In two of the three groups, the predicted lives correlated well with the observed lives on a one-to-one comparison. In all cases, the predicted lives were in the same time range as the observed lives. Overall, the frequency of predicted lives closely replicated the observed frequency of observed lives of the pillars in the data base of failed pillars. The method was successful in distinguishing between the data base of failed and a representative sample of intact pillars. While the predictions matched the observed lives of failed pillars, the predictions of expected lives for intact (hitherto unfailed) pillars were orders of magnitude greater. It is now possible to estimate the frequencies of future pillar failures for the purposes of mine closure and undermining of surface structures within broad bands.

Jan 1, 2003

By Parviz F. Rad

This Bureau of Mines report reviews laboratory and in-mine techniques for determining mechanical properties of coals, with special emphasis on the relationship between these properties and the minability of coal. An extensive bibliography is included.

Jan 1, 1973

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 E. G. Baglin

As part of an effort to decrease U.S. dependence on imports of critical and strategic metals, the Bureau of Mines investigated three leaching methods for extracting the base metals and recovering platinum-group metals (PGM) from matte prepared from Stillwater Complex flotation concentrates. Because of a limited supply of natural material, synthetic matte of composition similar to matte prepared from natural concentrates was used to devise the extraction sequences. The validity of the sequences was verified with matte prepared from Stillwater concentrates. In two-stage matte leaching, first-stage H2S04 leaching extracted 99 pct of the nickel and iron from the matte but negligible amounts of copper and PGM. Second-stage oxidative leaching with Fe2(S04)3 or FeC13 solubilized more than 98 pct of the copper and no precious metals. Sequential leaching, in which acid and oxidizing lixiviants were added sequentially to the matte without an intervening filtration step, extracted 99 pct of the Fe, Ni, and Cu. A roasting-leaching technique, in which the residue from first-stage leaching was roasted between 360° and 500° C before a second leaching with H2S04, solubilized 98 pct of the copper. The three leaching methods yielded high-grade PGM residues containing more than 98 pct of the PGM in the matte.

Jan 1, 1982

By S. Haggarty

"Wholly owned by Corona Corporation, the Nickel Plate Mine is an open pit, gold mining operation located near Hedley, 50 km west of Penticton, in Southern British Columbia.Milling capacity is 3,400 SDT /Day with an average feed grade of 0.080 Oz Au/Ton. Gold processing involves three stage grinding including tertiary pebble milling, two stage cyanide leaching and filtering and Merrill-Crowe zinc precipitation.A summary of process improvements required to increase milling capacity above the initial design tonnage of 2, 700 SDT /Day are described -Installation of a 42"" x 65"" Allis Chalmers Gyratory crusher replacing a 42"" x 48"" Traylor jaw crusher.Installation of polyurethane screen panels replacing woven wire cloths on an 8' x 20 ft triple deck screen.Installation of a hopper clarifier to reduce filtrate turbidity.Automated control of solution balancing and effluent treatment circuits.INTRODUCTIONThis paper describes mining and milling practices at the Nickel Plate Mine and details post start-up process modifications which were required to attain design tonnage.Wholly owned by Corona Corporation, the Nickel Plate Mine is an open pit, gold mining operation located near Hedley, 50 km west of Penticton, in Southern British Columbia.Mining capacity from the open pit is approximately 32,000 TPD with an average waste/ore ratio of 8.4:1.Milling capacity is 3,400 SOT/Day, above initial design tonnage of 2,700 SOT/Day. Feed grade averages 0.08 Oz Au per ton yielding 85,000 troy ounces of gold per year."

Jan 1, 1991

By Earl Sweet

This overview of economic and financial market prospects examines the current and future state of the global and Canadian economies with a focus on commodities. Housing prices and global conflicts all have effects on the overall economy and metal prices and mining developments in particular. This presentation outlines where we are today and where the author and BMO see the economy moving over the next few years.

Jan 1, 2016

By E. R. Bauer

In response to the mandates in the MINER Act of 2006, NIOSH conducted refuge alternatives research that included characterizing the utility, practicality and survivability of refuge chambers and outby safe havens. NIOSH also prepared and delivered a report to Congress in late December 2007 that summarized the findings of the research, included recommendations concerning the design and performance specifications for refuge alternatives, and focused on specific information that could inform the regulatory process on refuge alternatives. This document highlights NIOSH's research and recommendations concerning refuge alternatives, survivability evaluations of refuge chambers, and presents a brief review of the current deployment of refuge chambers in underground coal mines in the U.S. The research has lead to the conclusion that refuge alternatives have the potential for saving the lives of mine workers if they are part of a comprehensive escape and rescue plan, and if appropriate training is provided. DISCLAIMER: ?The findings and conclusions in this report have not been formally disseminated by the National Institute for Occupational Safety and Health and should not be construed to represent any agency determination or policy.?

Jan 1, 2009

By David H. Tang

Massive pillar failures were observed at two underground coal mines. The results of stability analysis using traditional pillar design formulae did not agree with the underground observations. Finite element models were used to analyze the causes and mechanisms of the pillar failures. The results were confirmed by the underground observations. Finally, the improved mine plan for each case was derived to ensure the stability of the underground structure.

Jan 1, 1990

By Louis P. Domingues

As part of a study on high-temperature ceramic materials, the ammonium sulfate, carbonate, nitrate, oxalate, and sulfate salts of yttrium, lanthanum, and cerium were analyzed thermogravimetrically. The temperature ranged from room temperature to 1,500° C. Each salt was decomposed by heating at a rate of 2.5° C. per minute, and some of the salts were subjected to additional rates of 5° C. per minute or 10° C. per minute. The decomposition sequences have been identified, and the temperatures of formation of intermediate compounds and of the oxides have been determined. The minimum oxide formation temperature of a given lanthanum salt exceeds that for the similar salt of yttrium, and both exceed that for the same salt of cerium except for one cerium carbonate. Variation of the heating rate indicates a thermal lag in the materials and produces the shift of formation temperatures to higher values and loss of resolution in the weight-loss distribution as the heating rate increases.

Jan 1, 1962

By Enrique Fernández

INTRODUCTION The high speed rail link between Madrid and Asturias, in the North of Spain, has encountered in the Cantabrian range the biggest challenge of the whole line, a very deep tunnel, 25 km long through a foreseen difficult geology. This tunnel was divided in the following four lots for construction: ¦Lot 1: Pola de Gordón- Folledo. L=10,7 km ¦Lot 2: Folledo-Viadangos. L=4,166 m ¦Lot 3: Viadangos- Los Pontones. East tube. L=10,4 km ¦Lot 4: Viadangos- Los Pontones. West tube. L=10,4 km. Dragados S.A. leading a JV was contracted to design and built the Lot 2 on the captioned Pajares High Speed Railway Tunnel. The Lot 2, comprising the middle third section of the 25 km long tunnel has an additional challenge: the construction of one access from the surface to allow it own construction. Feasibility reports and preliminary design do not foresee the use of TBM due to the risk of squeezing ground at the deepest area of the tunnel. On the other hand, conventional NATM excavation of the twin tunnels and ancillary works, including access shafts were against the expected construction schedule by the client, due to the poor ground foresee at the early stage.

By Robert B. Hopler

The history of the first twenty years of the high explosives industry in the United States begins as an illustration of the free enterprise system at its best and ends with the industry virtually taken over by a single company: a company which strongly opposed the new explosive material at the beginning of the period. In the world of the late Twentieth Century we could almost compare this history to the opposition of the mainframe computer manufacturers to the introduction of the personal computer, and their later entry into, and attempted dominance of, that market. With computers in the twentieth century the attempt to dominate the market has not been particularly successful: with dynamite in the nineteenth century it was.

Jan 1, 1994

By H. L. Jessberger

In recent years piled raft foundations of multi-storey buildings on weak soils have generated much interest and discussion. By taking account of the effects of each component of the system - the pile group and the raft - it is possible to reduce the settlements and inclinations of the system and to have an expedient load distribution on the piles and the raft. Thus the structural design of the foundation can be optimised.

Jan 1, 1991

By S. E. Olsen, K. Tang

The complex heterogeneous equilibria associated with the production of manganese ferroalloys have been simulated by employing recently developed thermochemical databases. The non-ideal Mn-Fe-Si-C alloy and the MnO-SiO2-Al2O3-CaO-MgO-FeO slag system have been modelled separately by the compound energy and cellular model. A large number of experimental thermodynamic and phase-equilibrium data were used to evaluate the model parameters for the liquid and solid Mn-Fe-Si-C phases. In addition to the liquid metal phase, solid mixture phases occurring in the Mn-Fe-Si-C system have also been studied. Over 500 measured equilibrium data have been utilised to verify and calibrate the model calculations. The paper will present typical simulation results, from activities of components to multicomponent heterogeneous equilibria. Good agreements can be obtained for many important technological parameters such as carbon solubility, phase relations and equilibrium diagrams, element distribution as function of temperature and slag composition etc. Application of the present models to the silicomanganese production will be demonstrated in this paper.

Jan 1, 2004