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By E. G. King

An earlier Bureau of Mines report4 provided low-temperature heat-capacity and entropy data for three sodium vanadates. This report continues the study of vanadates by presenting analogous data for three crystalline calcium vanadates - calcium metavanadate (CaV206), calcium pyrovanadate (Ca2V2O7), and calcium orthovanadate (Ca3V208). No similar data for these compounds have been published previously. MATERIALS All three vanadate samples were prepared by the Bureau of Mines by heating stoichiometric mixtures of reagent-grade calcium carbonate and vanadium pentoxide.5 Calcium metavanadate was prepared at 610° to 660° C. A stoichiometric mixture was heated for 17 days with intervening grindings, mixings, and adjustments of composition, as shown necessary by chemical analysis. The final analysis gave calcium oxide, 23.48 pct. (theoretical, 23.57 pct.) and vanadium pentoxide, 76.32 pct. (theoretical, 76.43 pct.). The sample also contained 0.11 pct. acid-insoluble matter. The X-ray diffracton pattern showed no lines of free calcium or vanadium oxides. No X-ray diffraction patterns were found in the literature for any of these substances.

Jan 1, 1961

President MRS. FREDERICK LAIST 24 Tompkins Road Scarsdale, N. Y. First Vice-president MRS. LOUIS D. HUNTOON Pleasantville New York Second Vice-president MRS. REED W. HYDE 84 Mountain Avenue Summit, N. J. Third Vice-president MISS MADELINE P. STONE 49 West 11th St. New York, N. Y. Fourth Vice-president MRS. JOHN J. LINCOLN Elkhorn, McDowell Co. West Virginia

Jan 1, 1932

By B Mohanty, M Alam, F Gauthuer

A series of eleven full-scale production blasts has been earned out in a limestone quarry to study the effect of delay interval and its precision on overall blasting performance. The quarry employed ANFO and cartridged aluminized emulsion in 75 mm diameter boreholes with 2.6 m burden and 2.9 m spacing on a 6.7 m bench. Both V-cut and echelon designs were studied. The types of detonators tested were regular short period electric detonators with expanding delay intervals, a more precise pyrotechnic-based electric detonator (EXADET) with a fixed (25 ms) delay interval, and the ultra-high precision electronic delay detonator (EDD) with constant (but site-selectable) delay interval. The various techniques employed to assess the blast results are described, and the performance of the three types of detonators compared. The use of both EXADET and EDD lead to improved blast results in echelon design. Of the three delay intervals (25 ms, 38 ms, and 50 ms) studied, the best results were obtained with EDD with a 38 ms delay interval, which translates into a delay of 38 ms/m of effective burden. The results also show the need for modification of current V-cut delay designs to derive full benefits from these high precision detonators.

Jan 1, 1991

As part of a comprehensive risk analysis which was carried out into the effectiveness of the water barrier between South Deep and Randfontein Estate mines, the potential threat posed by large seismic events was assessed. The study covered several aspects. Firstly, an estimate of the maximum credible earthquake was obtained from a probabilistic analysis of the regional seismicity of the previous 25 years. Allowance was made for ?reservoir-induced? effects by increasing the estimate of the size of the maximum credible earthquake from ML= 5.1 to ML= 5.5. Based on available knowledge of the geological structure, the possibility of such an event occurring in the vicinity of the barrier pillar was estimated. The possibility of substantial damage to the barrier rock mass, resulting as a consequence of a large event, was assessed. The likely damage to the concrete control plugs installed in five tunnels that penetrated the barrier, which might result from a ?near-miss? by the largest possible seismic event or from a ?direct hit? by a smaller event, was also considered. It was concluded that there was a negligibly small possibility that the maximum credible earthquake could occur close enough to the barrier, and in such a manner, as to cause any damage to it or to the plugs in the tunnels passing through it. The possibility of serious plug damage occurring as a result of a ?direct hit? by as maller event was slightly greater, but still sufficiently remote as to be of no practical concern at all.

Jan 1, 2006

By Lutz Markworth, Evren Ören

"The worldwide demand of ores and the depletion of the high-purity deposits make it necessary to recover ores in increasingly finer size fractions in the feed material. The flotation technology of more than 40 years old plants was not able to recover the ultra fine material. Those slurry tailings ponds now have the chance to be re-processed with PNEUFLOT® technology.The bubble sizes of different flotation technologies have a huge influence of the results especially regarding the recovery of the ultra fine particle sizes.PNEUFLOT® technology of HUMBOLDT WEDAG Coal & Minerals Technology GmbH in Germany was applied to ultra fine Phosphate, Copper and Platinum ores. The results will be presented in this paper.Conventional technology like agitator flotation has its limits in the flotation of fines due to turbulences in the cell. The position of the agitator influences the recovery of the fines. A deep impeller generates a higher froth zone. This helps to catch the medium fines. Due to the static head of the slurry inside the cell, compressed air is required for such cell designs.Column flotation is well known for a good selectivity without having in the first cell a good recovery. This leads to invest in several cleaning stages to reach an acceptable recovery. Further more, compressed air is required to generate the air bubbles to the flotation process, which are much bigger than with PNEUFLOT® technology applied.INTRODUCTIONHigh metal prices are actually the basis to invest in poor deposits or deposits with very fine intergrown ores which have to be milled down to ultra fine powders less than 60 micron. The liberation grade has to be determined by a mineralogical analysis. Polish sections have to be prepared and interpreted by using of a microscope. Figure 1 and figure 2 are showing polish sections of a platinum-nickel ore from Petchenga Nickel at Zapolyarni Mine in Russia. The head grades for rich ore are for copper between 0.05 – 0.15%, for nickel between 3 – 7% and for platinum group minerals approx. 0.15 oz/t. With an efficient flotation technology it can be upgraded to 20 oz/t."

Jan 1, 2009

By G. Taylor

A 21st Century worker is one who works less with his physical power and more with mental ability. Such a worker is more skilled than a labourer and is consequently rewarded accordingly. A21st Century supervisor is one who ensures that workers are constantly supported so that they can maximize safety and productivity. A 21st Century manager is one who constantly searches for ways to maximize returns for the various stakeholders. Given the well-known constraints in narrow reef mining, all of the above is meaningless unless a mining method is found which provides conditions which support the 21st Century initiatives. [ ] The identified mining method is a continuous non-explosive stope breaking system using rocksplitter technology. Rocksplitting is defined as: The fragmentation of rock through high energy pulse wave transmission in a fluid-filled hole or hydro fracturing. Shotholes are effectively filled with a water-based geland 30 grams of explosive after which the hole is closed off with a ?rocksplitting gun?.

Jan 1, 2000

By Daniel W. H. Su

The importance of incorporating fundamental principles of rock material response and failure mechanics into a pillar strength design model has been demonstrated. To accurately assess pillar strength, a model should account not only for the characteristics of the coal, but also for those of the surrounding strata. The interactions between the pillar and the surrounding roof and floor dictate ultimate pillar strength. Confinement, or the lack thereof, provided by roof and floor frictional end-constraint is one of the most significant factors in the strength of very wide pillars. The best conditions for end-constraint occur with ideally strong roof and floor. In this paper, it will be shown that weak roof and floor may decrease the ultimate pillar strength by as much as 30% compared to ideal conditions. Field observations confirm this pillar strength reduction in the presence of weak roof and floor. Furthermore, rock partings within the coal have a variable effect on pillar strength, depending on the parting strength. A competent shale parting within the coal reduces the effective pillar height, thus increasing the ultimate pillar strength; a weak claystone parting slightly decreases the strength. Imposed load distribution also has a significant effect on pillar strength, such that asymmetric pillar loading, similar to that observed in pillars adjacent to high extraction mining, reduces the ultimate pillar strength below that of equivalent pillars subject to uniform load distributions.

Jan 1, 1997

By L. E. Cardwell

This publication contains routine analyses and related source data for 377 natural gas samples from 19 States and two foreign countries. Of this total, 373 samples were collected during calendar year 1970. The remaining four samples were collected during previous years, but releases granting per-mission to publish the analyses were not received until 1970. All samples were collected as part of a continuous survey of the free world for occurrences of helium in natural gas. This survey has been conducted in the United States by the Bureau of Mines since 1917. In late 1965, the survey was expanded to include foreign gasfields. The analyses published herein were made by mass spectrometer and a special helium analysis apparatus, which are described in Bureau of Mines Bulletins 4863 and 576.4 Twelve previous publications have presented the results of 9,050 gas analyses prior to 1970. The first three, Bulletins 486,6 576,8 and 617,7 contain analyses and related source data on 5,218 gas samples collected from

Jan 1, 1971

By P Grieve, J L. Mauk

The Central Maratoto Valley in the Coromandel Peninsula contains a sequence of veins in pervasively altered dacite + andesites of the Waipupu Formation. We recognise at least eight different vein types: (1) pyrite stringers, (2) quartz + carbonate veins, (3) crystalline quartz veins, (4) carbonate veins, (5) chlorite + carbonate veins, (6) siderite veinlets, (7) siderite + carbonate veins and (8) carbonate + pyrite veins. The overall temporal trend of the veins is from early pyrite to quartz and then to late carbonate veins. Carbonate veins and pyrite stringers both form planar and irregular veins, whereas some carbonate veins have diffuse contacts with the wall rock. Gold and base metal sulphides are associated with some of the quartz + carbonate veins. Textures within the veins reflect open space filling and multi-phase reopening. A partial record of hydrothermal activity has been preserved by vein crosscutting relationships, hydrothermal alteration minerals and fluid inclusions. Hydrothermal alteration minerals display zonation from south to north. The alteration increases from unaltered to weak propylitic alteration of andesite in the south (MVRCDC1), to sericitic alteration of andesite and dacite in the north (MVRCDC3). The alteration assemblage is dominantly sericitic, with no adularia present, drawing parallels to the Thames region where there is no adularia.

Jan 1, 1999

For the year ending February, 1919 PRESIDENT SIDNEY J. JENNINGS NEW YORK, N. Y. PAST PRESIDENTS L. D. RICKETTS NEW YORK, N. Y. PHILIP N. MOORE ST. Louis, MO. FIRST VICE-PRESIDENT C. W. GOODALE BUTTE, MONT. TREASURER GEORGE C. STONE, NEW YORK, N. Y. SECRETARY EMERITUS ROSSITER W. RAYMOND, NEW YORK, N. Y. SECRETARY BRADLEY STOUGHTON NEW YORK, N. Y.

Jan 4, 1918

By A. M. Ouchi

Existing empirical design tools have been developed from fair-to-good quality rock masses (RMR76 >50). This paper presents a focus of ground control research presently being conducted by the Rock Mechanics Group in the UBC Mining Department in incorporating weak rock masses (RMR76 <50) into existing empirical design relationships. An emphasis is being placed upon the updated span design curve/critical span graph originally developed at UBC. The original database has been augmented with over 450 weak rock data points from mines such as the Stillwater mine (Montana), the Eskay Creek Mine (BC) and several mines in the Carlin Trend and other parts of Nevada. The original database is comprised of spans supported with ?traditional? mechanical bolting. In weak rock environments however, this type of support has been found for the most part, ineffective. This paper presents the span and weak rock RMR76 relationship for four different support categories. This work attempts to provide rock mechanic tools that will enable a mine operator to make economic decisions that will also ensure a safe working environment.

Jan 1, 2008

By Jeff Kravitz, John Kovac, Wayne Duerr

Since 198 1, Federal mining law has required every miner working in underground coal mines to have a self-contained, self-rescuer (SCSR) available for use in emergencies. Some miners that have escaped from fires using SCSR&apos;s have reported that they had to remove their mouthpiece to talk during escape, thus compromising the protection afforded by the SCSR. If miners are in thick smoke during an escape, they may have trouble if they become separated from their group. The visibility can be so poor that separation can occur at very short distances. To address this problem, two-way, FM radios were built into the SCSR to improve the ability to communicate should the miners be separated over relatively short distances. The SCSR prototypes built and used in testing included both two-way radios and improved mouthpieces. Comparison studies were conducted using combinations of the new and old mouthpieces, and trials using the radio or not using the radio. Subjective judgments indicate that communication ability was significantly improved using the prototype devices. Communication problems have been encountered with teams using standard voice- powered communications systems. Mine rescue teams perform rescue and recovery work under extremely hazardous conditions, life lines are a standard part of mine rescue team equipment. Leaky feeder and quasi-leaky feeder life line communications systems provide significant improvements over standard systems. These improved systems allow all members of the team to communicate with each other and their base of operations. These innovations will significantly enhance the safety of mine rescue operations.

By Wern-ping Chen

Technical and non-technical challenges exist in each mega infrastructure project. It?s no exception to the first US underground PPP Port of Miami Tunnel (POMT) project in Miami, FL. The POMT will connect two man-made islands, the Dodge and the Watson Islands, under the Biscayne Bay within highly porous limestone formation. Permeability as high as 0.1 cm/sec has been identified. Its 41-ft outside diameter, if constructed, is the largest precast segment lining in the US. Besides its geological and hydro geological challenges and risks, local community influence and impacts have controlled the fate of this project. This paper describes its tender design enhancements and the evolving of its slow advancement in resolving local community issues.

By T. Belem

The main objective of this study is to better understand the effect of underground CPB placement conditions on its microstructural, hydro-mechanical and geochemical properties. To reach this objective, three PVC columns, each 3 m high, were built, and were filled with CPB material. The columns allow simulating undrained (UD), half-drained (HD) and fully-drained (FD) conditions along with the measurement of resulting self-weight consolidation settlement of the CPB. Bleed and drainage waters were also collected from each column for geochemical analyses (pH, Eh, EC, SO42- content). After 90-days of curing time, a total of sixty CPB samples were cored from the backfill columns and subjected to uniaxial compression tests followed by physical characterization (Gs, void ratio, water content, degree of saturation, specific surface area). The results showed that the total drainage water and the maximum observed settlement occur mainly within the first 72 hours after the columns are filled. The corresponding volumetric strains suggest that in situ backfilled stopes simulated behave in a similar way to the fully-drained (FD) or the half-drained (HD) conditions. The MIP test results show that the pore structure varies between the top and the bottom of each column.

May 1, 2007

W. Johnson (Consultant, Adelaide) : Is there any mineralogical evidence of temperature of formation of the amphiboles and other minerals present in the crocidolite veins and country rocks7.N. A. Trueman: I am not aware of any definite evidence of the temperature of formation of these minerals, but am of the opinion that high temperatures would not be present during crystallization.No evidence from the qUl&apos;trtz, magnetite and hematite of formation temperatures is indicated and, as the carbonate is later than the other minerals it does not supply any data either.According to Miyashiro and other workers who have studied the composition and stability of the glaucophaneriebeckite series, minerals of riebeckite composition are stable over a wide range of P, T conditions. Recent work by W. G. Ernst, of the University of California, indicate that, in the presence of an Fe203/Fe304 buffer, riebeckite and crocidolite are more likely to form at low temperatures. The occurrence of riebeckite-crocidolite as authigenic minerals has been reported from several localities.Dr. MacLeod (Geol. Surv. of W. A.): Recent regional mapping by the Geological Survey of Western Australia has revealed a total thickness of at least 30,000 ft for the Proterozoic sediments in the Hamersley Basin. In this succession the asbestos-bearing beds of the Brockman Iron Formation at Wittenoom are overlain by some 20,000 ft of younger sediments and volcanics. With such a thickness of superincumbent material, it seems perfectly valid to involve

Jan 1, 1963

By F. J. Perzak

The Bureau of Mines conducted a flammability study of plastic ventilation ducts. Six rigid 16-in-diam fiberglass-reinforced plastic ducts from five manufacturers were examined using laboratory-scale, large-scale, and full-scale fire tests. The laboratory-scale tests included the American Society for Testing and Materials E162 radiant panel test, the E2863 oxygen index test, and the standardized small-scale flammability test (S3FT) developed by the Mine Safety and Health Administration (MSHA), U.S. Department of Labor, and replicated by the Bureau of Mines. Ten-foot lengths of the same ducts were also subjected to a large-scale vertical fire test, and 20-to 30-ft lengths were tested in a full-scale in-mine fire test at the Bureau&apos;s Lake Lynn Laboratory mine. The data from the laboratory-scale radiant panel test and oxygen index test indicated that the ducts were fire-resistant, However, five of the six ducts failed the S3FT and vertical fire tests, and four of the ducts failed the full-scale in-mine tests with flame propagation rates that ranged from 3 to 10 ft/min. The results indicate the need for improved fire-resistant plastic ducts. The good agreement between the S3FT re-sults and the vertical and full-scale tests show that the S3FT provides a good indication of the flammability of fiberglass-reinforced plastic ducting under realistic fire conditions.

Jan 1, 1987

By M. van Biljon

The possible closure and subsequent flooding of South Deep Gold Mine?s neighbouring Randfontein Estates Limited No. 4 Shaft (REL 4) necessitated the construction of five concrete plugs in the connecting tunnels to prevent the ingress of groundwater into REL4 from flooding South Deep mine. Several technical investigations had been carried out before and during construction of the plugs in order to reduce the probability of groundwater flow through the boundary pillar between the two mines or through the rock mass immediately around the plugs. This paper describes the geological, hydrogeological and stability investigations carried out to evaluate the structural competence of the boundary pillar.

Jan 1, 2006

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&apos;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 Tarrant Elkington

Underground mine planning practices are typically manual and time consuming and will often produce sub-optimal solutions due to the application of generic rule-of-thumb assumptions or ?tried and tested? choices. The development of computer-automated tools for underground mine planning enable a wide range of scenarios to be considered rapidly in arriving at an optimised solution, subject to input assumptions. We have applied these tools to demonstrate ?optimised? solutions that challenge industry standard practices. Further, we have incorporated grade and price/cost uncertainty into these tools to gain an understanding on how the consideration of uncertainty may further alter strategy selection. Finally, we enable the tools to dynamically adjust cut-off grades in conjunction with the evolution of prices/cost.

May 1, 2010

By Marilyn Biviano

(l)The direct economic costs to this nation resulting from a decision to embargo South African strategic and critical minerals imports are estimated at $1.85 billion per year.2,3 About 94 percent of these estimated costs are for two platinum-group metals (PGM&apos;s), platinum and rhodium. The estimated costs of a 5-year embargo beginning in 1988 for the strategic and critical minerals analyzed are presented in Table 1.4 (2)There are sufficient alternative world sources to South Africa for manganese, chromium, palladium, titanium, and vanadium to meet U.S. industrial demand in the event of an embargo. (3)Alternative world sources to South Africa for platinum and rhodium cannot meet U.S. industrial demand. Non-South African world supply sources can meet about 40 percent of domestic platinum consumption requirements and 50 percent of rhodium requirements. (4)As a result of the increase in prices for platinum and rhodium during the embargo, expansion of domestic platinum-group metals mining and secondary production is expected. During a five year embargo, domestic primary and secondary production expand and together satisfy about one-third of U.S. platinum requirements, one-third of U.S. rhodium requirements, and over one-half of domestic palladium requirements.

Jan 1, 1988