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By Jean Habimana

Complex and distinct geological units spread along the 7-mile long 30-ft inside diameter Upper Rouge Tunnel CSO Control Project in Detroit, Michigan. Its construction is divided in two tunnel construction packages: The South Tunnel, to be driven in finely laminated weak TG Limy Shale, will be excavated by a shielded TBM with precast concrete segmental lining, while the North tunnel, predominantly in a relatively more competent geologic formation Antrim Shale, will be excavated by a main beam TBM with a two-pass lining system. The adits and deaeration chambers will be excavated by sequential excavation method. This paper addresses the process of selecting excavation methods and lining systems for shafts, tunnels, connecting adits, and deaeration chambers.

This paper describes the behaviour, under creep conditions, of a cast lead creep specimen consisting of five crystals, the boundaries of these crystals being substantially at right angles to the direction' of tension, i.e., across the long axis of the specimen. This particular specimen was obtained in an attempt to produce a single crystal in the manner described in the appendix of a previous paper (1).Thus, the specimen was of the same shape and size, was composed of the same purity lead and received the same preliminary treatment as the single crystal test-pieces.The object of the experiment was mainly to observe the effect of the crystal boundaries on both the deformation of the test piece and the process of recrystallisation and to compare the creep rate of the test-piece with that of a specimen consisting of one crystal only.EXPERIMENTAL METHODThe specimen had an effective test length of 10 cms. and a cross $ection of 0·5 in. x 0·25 in. In Fig. 1 is given a sketch of the specimen to scale showing the positions of the crystal boundaries on all four surfaces. Except for those of crystal No. 4, which was confined to approximately one-half the cross section of the specimen, the boundaries of each crystal traversed the four faces.The specimen was mounted in exactly the same manner as the single crystal specimens. During the creep test, it...

Jan 1, 1941

By David M. Jurich, Randy J. Essex, Alex de Aboitiz

An Automated People Mover (APM) transit system is planned for the growing Phoenix Sky Harbor International Airport. The APM will improve passenger movements between the terminals, and provide a link to parking facilities, a new rental car facility, and the planned metro Light Rail. The underground works will include shallow twin bored tunnels, taxiway crossings, and underground stations constructed beneath critical airport facilities. Challenging soft ground conditions will require extensive underpinning and ground improvements. Design is underway, and construction is scheduled to begin in 2007 with project completion in 2015. The owner’s planned delivery method for the APM Project will be Construction Manager at Risk (CMAR) with a Guaranteed Maximum Price.

Jan 1, 2005

By Mutombo Nombe, Avimanyu Das, Rick Honaker

Enhanced gravity separators (EGS) provide a more efficient separation than froth flotation when cleaning coal in the 150 x 25 µm particle size range. To improve the performance of an EGS unit, air bubbles were injected into the feed stream in an attempt to decrease the apparent density of the coal particles due to the formation of bubble-coal particle agglomerates. Air injection had a significant impact on operating characteristics and separation performance. Coal recovery was increased by 10 to 20 absolute percentage points while a 2 percentage point drop in the minimum product ash content was also achieved.

Jan 1, 2005

By Harry Dobroski

Communications with moving tracked vehicles in a rail haulage mine pose a difficult problem. These communications take place from dispatcher to vehicles or from vehicle to vehicle via the trolley line, which is a very poor communications line. As a result, deadspots and high-signal areas can occur anywhere along the line, or signal can decrease simply as a function of distance. An analysis is made of the trolley line as a communications line, and methods of improving its characteristics are discussed. Data from inmine experiments are presented, showing actual improvements in communications. Recent Bureau developments in new hardware are also discussed. These include an adaptive speaker control for existing carrier phones and a new generation of improved carrier phones.

Cessation of mining on the Bendigo goldfield makes it evident that, as the older generation fades away, knowledge of the famous Bendigo saddle reefs will be limited in the future by their written records. It is important therefore that the summarised account by D. E. Thomas (1953) in the Geology of Australian Ore Deposits should not be misleading. Fig. 6 in this article is stated to portray a cross section and longitudinal section through a series of gold shoots in the Garden Gully 300 ft. reef. The gold shoot along the capof the saddle reef is represented as extending down the east leg in a series of prongs, with the tips of the prongs about 50 ft. apart. It is the purpose of this note to indicate that this illustration can be suspected to be a diagram of the old stopes instead of a diagram of the distribution of gold in the quartz.The original sketches of Figs. 6 and 7 in Thomas' account were extracted, I believe, from the field note books of H. S. Whitelaw, years after his death in the late twenties. Whitelaw was stationed in the Bendigo office of the Geological Survey of Victoria, carrying out geological surveys of the Bendigo mines. He was there for many years before the Gold Research committee started its investigations in 1916 and he was acutely aware of the problem attached to the distribution of gold in the reefs. He had felt concern that manyauriferous reefs were being mined without adequate study and record and he decided, as he expressed it to me, to pick up what he could as he went along. There can be little doubt that the diagrams of Figs. 6 and 7 are products of this resolve.Opportunities to investigate gold occurrences at Bendigo were limited before 1916 because the field was operated by Manuscript received at The Institute 18th November, 1960.

Jan 1, 1961

Detailed mineralogical investigation of a tailing sample from the Juno plant circuit at Tennant Creek was carried out to determine the nature of the unrecovered bismuth and whether any possibility existed for improving bismuth recovery. The investigation showed that the Ibismuth was present in a complex mixture of Bi-Pb-Ou-Se-S minerals (termed "bismuthinite"), of which about 74 per cent was locked (mainly with magnetite) and 26 per cent was liberated (18 per cent in the minus 7 µm slime). The results suggested that attention should be directed to both finer grinding and improved flotation of slime "bismuthinite", and testwork carried out by Peko Mines N.L. on the basis of these recommendations led to a significant improvement in bismuth recovery.Detailed mineralogical investigation of two Juno concentrates was carried out to determine the nature of the selenium present and whether any possibility existed for improving the selenium grade. The investigation indicated that virtqally all the bismuth, selenium, and lead was present in "bismuthinite", which showed a composition range of 32-82 per cent Bi, 0-42 per cent Pb, 0-24 per cent Se, and 5-18 per cent S. Differences in the Bi/Se ratios of the two concentrates could be attributed to different average Bi/Se ratios of the constituent "bismuthinite", and the relatively low selenium grade of the "bismuthinite" precluded the possibility of obtaining a high grade selenium concentrate with high selenium recovery.However, differential flotation and/or low intensity magnetic separation to remove chakopyrite, and magnetite, the main diluents of the concentrate, could be expected to upgrade the selenium content byup to 80 per cent (relative) and .festwork carried out by Peko Mines N.L. on the basis of the recommendations of the mineralogical investigation confirmed that depression of chalcopyrite in the flotation circuit could produce significantly improved selenium grades.These investigations illustrate the application of mineralogy to the practical problems of improving plant performance. Mineralogy has an important role to play in providing quantitative data on which the metallurgist can evaluate plant performance and base a programme of metallurgical testwork, and early mineralogical investigation of feeds, concentrates, middlings, and tailings can lead to the avoidance of much abortive and expensive metallurgical testwork.

Jan 1, 1974

By William R. Barton

Sampling to determine development potential of beryllium deposits was conducted at 31 New England localities. A total of 54 additional areas where the geochemical environment appeared favorable were sampled to determine if economically interesting percentages of beryllia (BeO) might occur. Newry Hill-Plumbago Mountain, Maine, Iron Mountain, N.H., and Long Island, Maine, were investigated in some detail to determine the size and grade of deposits. The mineralized pegmatites at Newry Hill-Phunbago Mountain are extensive but very low grade; at Iron Mountain the ore bodies are very rich but of small volume; at Long Island beryl occurs with molybdenite, wolframite, and scheelite, but the tonnage of ore was not determined.

Jan 1, 1968

By Lawrence J. Froisland

To aid in minimizing adverse environmental impacts of mining and mineral processing, the Bureau of Mines studied changes in soil characteristics in topsoil stockpiled during mining operations. Topsoil stockpiles in arid areas of New Mexico, Utah, and Wyoming were sampled over a 1- to 8-yr period to determine any changes in physical, chemical, or biological parameters in the top 15 ft of soil. Parameters examined in this study included soil moisture, pH, electrical conductivity, and cation exchange capacity; total nitrogen, organic carbon, carbon to nitrogen ratio, extractable potassium, and soluble phosphorus levels in the soil; general levels of bacteria activity in the soil; and productivity of the soil as measured by shoot yield in growth tests. Data were analyzed by multiple linear regression to determine possible effects of stockpile age and depth. Bacteria population counts, used as an indicator of goner l bacterial activity, was the only parameter found to be significantly correlated with stockpile age and depth at more than one site. Bacterial activity increased with depth at the two sites where it was measured. Activity increased with age at one site and decreased with age at the second. Significant changes in soil pH, electrical conductivity, and moisture were significantly correlated with stockpile age and depth at single sites. This study did not show significant, consistent deterioration in soil characteristics or growth yield of topsoil stored in stockpiles.

Jan 1, 1987

Experiments on High Efficiency Separation of Mixed Plastic Wastes by Vortex-Tube Separator

Sep 13, 2010

By Greg Sheppard, Eduardo Nebot

Australian researchers have developed new technologies aimed at improving safety and productivity at openpit mines. A data acquisition and feedback system for electric rope shovels has been shown to substantially reduce cycle times and decrease excessive machine duty caused by stalls. This data acquisition system was developed by the Cooperative Research Center for Mining Technology and Equipment (CMTE). It has been tested on a P&H 4100A shovel at Coal & Allied’s Hunter Valley operations and a P&H 4100XPB at BHP Billiton Mitsubishi Alliance’s Goonyella Riverside Mine in Central Queensland. In addition, CMTE member P&H Mine Pro Services has used the technology to acquire field data from a P&H 4100XPBrope shovel at RAG’s Belle Ayr Mine in Wyoming’s Powder River Basin.

Jan 1, 2002

The copper-clay deposits consist largely of goethite and clayey mudstones carrying native copper, cuprite, and chalcocite. The mudstones are of Ordovician age, are interbedded with Fe-Mn carbonates, and probably contained syngenetic iron and copper sulphides. The secondary copper minerals have been derived from post-Devonian weathering in situ and also by deposition from surfaee and underground waters draining the adjacent mineralized volcanic rocks.

Jan 1, 1969

By H. B. Carroll

This Bureau of Mines report evaluates the performance of commercially available portable instrumentation for the detection of carbon monoxide, carbon dioxide, oxygen, and methane at conditions simulating an industrial work atmosphere. Portable instrumentation included in the study was gas-detection tubes (length-of-stain and color intensity), catalytic detector, liquid absorption detectors, paramagnetic oxygen detector, galvanic detector, and pelement or hot-wire methane detectors. Evaluation of the instruments was in atmospheres with 50 and 80 percent relative humidities at 75° F and containing test gas concentrations of 0.1, 0.25, 0.50, 1.0, 1.5, and 2.0 times the thresh-old limit value. Correlation of the results from the portable gao analyzer with measurement from the standard instruments was made by calculating and plotting an estimated line of regression, prediction, and confidence limits and the correlation coefficient for each detector system. Relative humidity in the 50-to 80-percent range did not appear to contribute to instrumental uncertainties in either performance or operation. Considerable deviation in detection precision between the portable gas-detection systems and the standard systems was established, especially at the lower gas concentration levels. The main difference or inconsistency in toxic gas concentrations determined with length-of-stain tubes resulted from the observer's interpretation of the results rather than difference in the tubes themselves.

Jan 1, 1973

By S. Ndlovu, M. Malatse

"The Witwatersrand Basin is the heart of South Africa’a gold mining industry. The cluster of gold mines located in the Witwatersrand Basin generates a significant amount of mine tailings, which have adverse effects on the environment and ecological systems. In addition, disposal costs are very high. The exponential population growth in the Witwatersrand area has resulted in pressure on the reserves of traditional building materials. Quarrying for natural construction material is very expensive and damages the landscape. This work therefore examines the use of gold mine tailings in the production of bricks.Different mixing ratios of gold tailings, cement, and water were used. The resulting bricks were then cured in three different environments - sun dried, oven dried at 360°C, and cured in water for 24 hours. The bricks were then tested for unconfined compressive strength, water absorption, and weight loss. The results showed that the mixture with more cement than tailings had a compressive strength of approximately 530 kN/m2. It was also found that the best brick curing system was in a water environment. Bricks made from tailings cost more than conventional bricks because of the higher quantity of cement used, but the manufacturing process consumes less water. Overall, the results indicated that gold mine tailings have a high potential to substitute for the natural materials currently used in brickmaking.Paper written on project work carried out in partial fulfilment of BSc. Eng. (Metallurgyand Materials Sciences)"

Jan 1, 2015

By Giuliana A. Zelada-Tumialan

Reduced workability and flowability of the concrete through the tremie tubes and drilled shaft reinforcement have been identified as the main causes of tremie-concrete drilled shaft concrete defects. This paper discusses two recent case studies of defective tremie-concrete drilled shafts. The defects (soft inclusions, aggregate segregation, and low concrete strength) were primarily caused by the combined effects of the tremie placing sequence, rapid concrete slump loss, and poor passing and blocking characteristics of the approved concrete mix design. The level of detail contained in the drilled shaft specifications varied between projects. However, even when the specifications incorporated several of the more recent recommendations for tremie-concrete placement, the case studies showed that typical provisions for concrete mix proportioning and placement can be further improved to minimize construction defects such as those described in this paper. Based on the findings of the case studies presented, recommendations for the development of more effective specifications are provided. The recommendations include requirements for mock-up testing of proposed concrete mix designs and evaluation of the tremie-concrete placement sequence. Performance of such testing and evaluation would greatly reduce the potential for drilled shaft defects and consequent time and financial burdens associated with them.

Jan 1, 2009

Soon after the Rosebery concentrator commenced operations in 1936, an investigation was begun in an attempt to discover a substitute for cyanide in lead flotation. Cyanide is an excellent depressant for zinc and iron, but it also powerfully depresses the copper, silver and gold bearing minerals present in Rosebery ore, thus allowing them to pass through to the zinc concentrate or final residue where they are of little or no value.The investigation was not entirely successful, but it did indicate that sodium bisulphite or sodium sulphite could be used as a depressant for zinc without depressing the copper, silver and gold bearing minerals. The sulphites were, however, much inferior to cyanide as apyrite depressant.At about this time, I. W. Wark, using the captive bubble technique, had shown that, at the concentrations normally used, sodium aerofloat is not a promoter for pyrite or galena in alkaline solutions (see his book "Principles of Flotation", p. 188). Some preliminary tests on the production of a copper concentrate from Rosebery ore were therefore carried out using sodium sulphite as depressant and sodium aerofloat as promoter.The results of this work were promising but, since Rosebery ore usually carries only about 0·5% copper, there did not seem to be much incentive to carry the work further. With the outbreak of war, however, Australia became desperately short of copper and the relatively small amount in the ore. became of sufficient importance to...

Jan 1, 1952

The success of smooth blasting essentially depends on geological condition of rock. Also, in the perimeter hole, borehole pressures with light, well-distributed explosive loads are important to minimise overbreak. In order to simulate perimeter holes with scaled model test, the borehole pressure was considered as a factor of scale. Hydraulic oil pressure is applied as borehole pressure instead of using explosives and detonators in order to remove the undesirable effects of detonators in an experimental set-up of just two perimeter holes in a tunnel blast. The borehole pressure on a perimeter hole is nearly reproduced with hydraulic pressure which is generated by non-electric detonators in the hermetical cylinder.

Dec 6, 2010

All previous attempts to cut rock in boring by means of revolving steel cutters have failed, chiefly in consequence of the mis-shapen teeth grinding the rock and themselves simultaneously, until, after a very few revolutions, the points of the cutters were so worn that it was impossible to force them into the strata. The diamond drilling plant being cumbrous, complicated, and costly, and seeing that fully 70 per cent of the boring generally needed is in what is known as the" milder strata," it will be readily understood that much of the work done will not pay a dividend on the outlay, so great is the cost of removal, the wear and tear of the machinery, and the loss of diamonds. The Calyx Drill, however, invented by Mr. F. Harley Davis, has been constructed so as to overcome these difficulties, and will penetrate quickly and .at a low cost this 70 per cent. of the milder strata. The Drill has taken ten years' hard work and thought to bring it to its present state of perfection, and it will now drill with steel cutters the 70 per cent of the work performed by the diamond drills at a greater speed and at about one third the cost of the latter.The utility of the diamond drill for certain work is undeniable, but it cannot by any means be described as a machine of general popular usefulness that is to say, it is quite beyond the reach of the great masses of mankind.

By H. C. Fowler

The social economy, or public interest, and national defense require wise development and efficient use of the oil and gas resources of the United States. In this development and use, and in the prevention of economic and physical waste of oil and gas, the objectives of the petroleum and natural-gas industries, the Government (Federal, State, and local), and the public are the same. Differences of viewpoint generally have originated in the failure of one of the triad to have a clear or complete understanding of the motives behind the activities of the other component groups or full knowledge of what each is trying to accomplish. The Unites States Bureau of Mines through its petroleum and natural-gas division makes technologic and scientific investigations pertaining to recovery,3 preparation, refining, and use of oil and natural gas with the view of reducing waste, increasing safety and efficiency and aiding economic development.

Jan 1, 1933

By William C. York-Feirn, Jeffrey H. Kravitz, David Stalfort

"Mining is an inherently risky business. Over the years, major mine disasters have resulted in the deaths and injuries of thousands of miners in the United States. These disasters also resulted in innovations in approaches to mine design, operations and the training of miners and mine rescue teams. The U.S. Congress responded to these disasters with new laws designed to create mandatory safety and health standards as a means to eliminate fatal accidents; to reduce the frequency and severity of nonfatal accidents; to minimize health hazards and to promote improved safety and health conditions in the nation’s mines.Following a mine emergency preparedness and response holistic gap analysis in 2012, the U.S. Mine Safety and Health Administration (MSHA) identified the need for the development of risk and readiness assessment models for MSHA and the mining industry. MSHA’s objective was to evolve existing theoretical concepts for risk and readiness assessment into simplified tools that can be applied by the mining industry for use at operational levels. In 2012, MSHA hired ABS Group, a recognized industry leader in safety risk management and a wholly owned subsidiary of the American Bureau of Shipping, to develop self-assessment models to help meet this objective.In September 2012, MSHA chartered a project to supply the coal mining industry with a pro-active toolset for mine operators to:1. Self-assess the risks associated with underground coal mining operations in order to prevent major mine emergencies.2. Assess the preparedness of mine operators to respond to an emergency.3. Measure the readiness of mine rescue teams and responsible persons to execute emergency plans.MSHA’s objective was to evolve existing theoretical concepts for risk and readiness assessment into simplified tools that can be applied by the coal mining industry for use at operational levels."

Jan 10, 2018