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By A. V. De Forest

INSPECTION and test methods of great diversity have been used from the most ancient times to select raw material, control its manufacture, and appraise its finished properties and value. The "miller thumb," expert in grading flour, the vintner's sense of taste, the goldsmith's micro-wear test on a touchstone, the enquiring sniff over the doubtful egg -these are all nondestructive inspection methods, accurate and depend- able, but not readily reduced to numbers in the c.g.s. system. A horse trader inspecting a possible purchase is interested in more than age, size, weight, color. heredity, speed, or drawbar pull which can be reduced to figures. Behavior, temperament, stamina, health-past, present and future---are just as important as the numerically determinate constants.

Jan 1, 1940

This publication summarizes the Bureau's activities as part of a study of the Juneau Mining District (JMD) during the period 1984-1988. The objectives of the program were to identify the type, amount, and distribution of mineral deposits in the district, determine ore reserves, study beneficiation technologies for the ore, make feasibility studies, and address economic and legislative effects on mineral development. The JMD study was a cooperative study involving the Bureau and the Alaska Division of Geological and Geophysical Surveys (ADGGS). Over 30 employee-years were spent by the Bureau on this project. Bureau investigations in the JMD consisted of a district-wide investigation of industrial materials in addition to site-specific investigations of precious and base metals in five subareas. During the 4 years of the JMD study, more than 300 areas, mines, prospects, and occurrences were visited, which contain gold, silver, copper, zinc, lead, nickel, cobalt, tungsten, molybdenum, chromium, and platinum group metals (PGM). More than 59,000 feet of underground workings were mapped and sampled. More than 5,500 samples were taken; one diamond drilling program and three geophysical surveys were completed. An up-to-date and complete mineral data base for the JMD did not exist prior to this study. The JMD study, which coincided with a tremendous increase in mineral interest and activity in the district, has proven to be valuable to both the minerals industry and land management agencies. The discovery of two new mineral occurrences and compilation of data on known mines, prospects, and occurrences have aided industry activity in the region. The study enabled timely data to be available to land management agencies at the Federal, State, and municipal levels.

Jan 1, 2012

By Don Thompson

Canada’s oil sands are a controversial topic and virtually every newsmaker and layperson seems to have an opinion about this 179 billion barrel resource. The oil sands represent 97 per cent of Canada’s remaining oil reserves, but misinterpretation and misrepresentation of the facts are threatening development of a resource that generates significant employment and tax revenue for Canadians. Join Don Thompson, president of the Oil Sands Developers Group, as he dispels the top ten myths about Canada’s oil sands and presents an alternative perspective on an industry that can play a critical role in North America’s economic recovery.

Jan 1, 2010

By Paul T. Alexander

After evaluating preceding studies and designs of lightweight supports, ESD selected the all-hydraulic and the hydromechanical concepts for detailed design and fabrication. Further analysis and testing showed that the all-hydraulic design was economically justified and met all the crucial engineering, manufacturing, and design criteria identified during the evaluation phase. Following Bureau of Mines approval of the detailed design, four all-hydraulic support models were fabricated. Once functional and structural testing was successfully completed, 40 additional units were constructed and distributed for in-mine testing. The units were very well-liked by all three demonstration mines. The wide- spread interest in supports for seam heights greater than 8 feet led to expansion of the design data package. ESD designed four basic models to cover the new height range, but no hardware has yet been fabricated for the new design.

Jan 1, 1982

By C. Frenzel, N. Blechschmidt

"INTRODUCTION There is no doubt about the time and effort companies put in establishing and maintaining their equipment. However, the question about how these companies can map the benefits comes up. Neither do they have the tools to quantify the benefit of their action, nor do they have the tools to know the actual quality of their current maintenance system. The resources used in the process seem futile to observers. It seems impossible to trace improvements and to get information about the impact of actions in retrospect. Improvements in maintenance performance cannot be recognised by management or shareholders. Thus the necessity for measuring the performance of maintenance systems is given. In this paper ConMoto is systematically showing the strengths and weaknesses of many companies' maintenance management and is providing field-tested proven design elements for measuring maintenance systems and implementing Value Oriented Maintenance. Considering only business assets in production facilities and related machinery out of all investment goods in Europe, you reach a value of around 9.7 trillion euros in 2008. In Germany alone the equipment replacement value amounted to about 1.9 trillion euros [8,10,11,13]. If you calculate a cross sector maintenance costs rate of 4.8 % (corresponding to the average value identified in this study), direct maintenance costs in European production locations add up to over 450 billion euros per year [3]. These figures speak for themselves. Yet maintenance is not only of enormous significance for European enterprises. Our experiences show that maintenance and asset management, particularly sustainability issues, are also increasingly moving to the forefront in the BRIC states, in the Middle East and in many emerging countries. First of all, in order to meet the resulting high quality and cost related requirements of maintenance systems, a comprehensive overview of the issue is needed. This overview is provided by a detailed analysis of 83 companies and production plants from various sectors – with amazing results. SIGNIFICANCE OF MAINTENANCE Current studies show the high financial significance of maintenance and asset management. According to the market study in the Asset Manager [9], in industrialised countries about 10 to 15 per cent of the labour force are employed in maintenance and facility management tasks. In Europe about 40 to50 million people are directly and indirectly involved in retaining the value of machinery, plants, buildings, transport systems and infrastructure facilities. A glance at the costs side also demonstrates the great relevance of maintenance. EU-wide annual direct maintenance costs amount to a total of more than 1,500 billion euros. In Germany alone they are about 250 billion euros. This impressive total is considerably exceeded by indirect maintenance costs caused by technical failures. Indirect costs are estimated to be five times higher (Figure 1). [7,12,14]"

Jan 1, 2018

By S. L. Huang

The location and shape of potential failure surfaces in soil slopes were directly determined based on the stresses induced in the soil mass and the strength of the soil itself. Stress calculations were carried out by the finite element method with the Drucker-Prager nonlinear material model. The Mohr-Coulomb failure criterion and Mohr's circle stress analysis were then applied to the calculated stresses to determine the characteristics of the failure surface.

Jan 1, 1989

By Ian R. Muirhead

Over the past year or so, a number of mining companies have been meeting to examine the role of research in surface mining and, in particular, how to establish a collaborative research effort for the surface mining industry. A review has been completed which has identified the topics that are of interest to the surface mining companies for undertaking collaborative research. This has identified key subject areas such as Operations & Equipment; Maintenance; Environment & Reclamation; and Stability. Specific research projects for the initial research effort have been selected which include Wireless Data Communications, Analysis and Management; Application of GPS in Mining; and Tires for Heavy Haulers. In addition, attention has also been focussed on finding a suitable low cost, but effective, organization to coordinate and manage the collaborative research. The recently formed CONRAD Organization (Canadian Oilsands Network for Research and Development) appears to be a suitable candidate and discussions are ongoing with that group. This paper provides a summary of the review of surface mining research needs and of the status of the establishment of a collaborative research body for surface mining.

Jan 1, 1996

By Mike Watts

Since the first longwall panel development started in the new mining, (Southern) area, a number of roof falls have occurred in L1 and L2 gate-entries. The longwall was delayed for a total of two months due to roof falls in the gate-entries. To prevent roof falls in future gate-entries, an extensive ground control analysis has been conducted which incorporated regional horizontal stress and panel orientation, tectonic stress, roof strata, surface stream valleys, etc. Results of the analysis indicate that a combination of these factors caused the roof falls. Therefore, a Roof Instability Rating (RIR) system was constructed to predict the roof condition and identify areas where supplemental support should be implemented. The L3 gate-entries, supported by the prediction using the RIR system, have not experienced any roof problems.

Jan 1, 2000

By R. Marleau, R. Assad, J. Dugas

"A study of the geological features of known occurrences of mineralization in Gaspe is the basis for a classification. Nickel, chromite, asbestos and some copper are pre-or syn-Taconic, whereas the most important deposits are tied to granitic post-Taconic stocks. Most occurrences are clearly related to igneous rocks: nickel, chromium and asbestos to Ordovician serpentinite; copper to volcanic rocks of different ages; and copper, zinc and lead to acidic intrusions with apparent zoning. Some lead-zinc deposits lying between the Grande Greve and York Lake formations are stratigraphically controlled. Some occurrences are tied to faults; e.g., the nickel-copper mineralization along the North Grand Pabos fault. Northerly-trending transverse structures appear to coincide with the Gaspe Copper, Mount McGerrigle (Tabletop) granite and Lemieux dome areas of mineralization. JEAN DUGAS, after graduating"

Jan 1, 1969

By M. Fan, M. Mankosa, G. Luttrell

"Column and other non-conventional flotation approaches continue to provide benefits where conventional flotation processes have exhibited limited success. This is particularly evident with respect to flotation of ultrafine and coarse particles. Advancements in air sparging technology have provided the ability to produce finer bubbles than previously possible. The generation of finer bubbles coupled with the froth washing capabilities of a flotation column has demonstrated improvements in ultrafine particle recovery while simultaneously producing a high-grade float product. On the other side of the spectrum, the use of these sparging technologies while applying flotation fundamentals to a fluidized-bed reactor has increased the maximum floatable particle size up to and in excess of 3 mm. Benefits of higher recoveries and reduced reagent consumption have resulted from the use of these technologies. An additional benefit includes a reduction in plant grinding requirements. As such, this paper describes the application of Cavitation-Tube sparger technology and fluidized-bed flotation (HydroFloat). A review of data from industrial and pilot-scale applications is also provided.INTRODUCTIONConventional (mechanical) froth flotation is considered the workhorse of the minerals processing industry. This low-cost process makes it possible to selectively recover minerals by exploiting the difference in surface characteristics (e.g., wettability) of the valuable component and the waste material. Unfortunately, the upper particle size limit for flotation rarely exceeds 0.600 mm, and is typically maintained at less than 0.300 mm for most industrial applications. For many commercial base metal plants, the particle size range for optimum recovery is typically between 0.01 and 0.1 mm (Lynch et al., 1981). This finding is not novel. In fact, the effect of particle size on flotation recovery was studied as early as 1931 by Gaudin et al. who showed that coarse (+0.250 mm) and extremely fine particles (-0.010 mm) are more difficult to recover than particles of an intermediate size. The loss of recovery is due to inherent limitations associated with the flotation process, including bubble-particle adhesion and collision, detachment, buoyancy, and transport."

Jan 1, 2010

By D. J. Burdon, Anthony Caplan

"(1) The radiological appearances of pneumokoniosis on the Kolar Gold Field is described in detail. The characteristic abnormality is the. presence of a diffuse, fine annular and punctate mottling. (2) The frequency of symptoms could not be determined with any degree of accuracy, but it is believed that symptoms are absent and there is no incapacity until profuse radiological mottling is present, i.e., after long exposure to dust. (3) There is an increased predisposition to tuberculosis, which, if it occurs, affects the prognosismost unfavourably.(4) Pathological examination shows that the radiological mottling is due to the presence inthe lung of numerous small dust-cdll aggregates (up to T5 mm. in dia.) deposited around the smaller bronchioles and blood-vessels.(5) The dust-cell aggregates are relatively acellular but when tuberculosis is superadded thereis an excessive cellular and fibrotic reaction.(6) The difficulties of defining the radiological and pathological appearances of early pneumokoniosisare discussed.(7) The incidence of pneumokoniosis in 7,653 workmen with 5 or more years’ undergroundservice was 43-75%, but it is suggested that in future the incidence will be appreciably lower.(8) The methods of- dust production and the chemistry of mine dust are described. It isshown that the free silica-content of air-borne mine -dust is relatively low.(9) The aetiology'of the pneumokoniotic lesion is discussed."

Jan 1, 1947

By James P. Sloss

MOST students that plan to enter the mining profession attempt to obtain some kind of practical experience before graduation. Six or seven years ago it was an easy matter for undergraduates to find employment during the summer vacation and return to school in the fall filled with enthusiasm to dig deeper into the theoretical field. However, during the past few years it has become extremely difficult for an inexperienced undergraduate to obtain even a menial job in mining. This was the situation which presented itself to the author and his partner, T. M. Patten several months before school closed in May, 1934. At that time, Mr. Patten's training consisted of two years study in Mining, and mine included three years' study in Mining Geology at the Missouri School of Mines and Metallurgy. With this technical training and no practical experience, we conceived the idea that custom assaying in some of the western mining districts should be a lucrative business. We thought that the renewed interest in prospecting for gold and the opening of new mines should provide more assay work, and believed that we might secure it if we were on the spot where the assaying was needed. We realized that it would be out of the question for us to obtain the necessary equipment with which to establish an assay office. Even if such an office were established we had a maximum of but three months during which to operate. So we determined to build some kind of inexpensive equipment that could be placed in an automobile, or trailer, and be moved from one camp to another. We then began to study the theoretical aspects of assaying and started experimental work with the equipment that we proposed to build.

Jan 1, 1935

By F. S. Young

Previous laboratory and field experimentation has demonstrated the effect of several variables on drilling rate.1-5 These results have been incorporated into optimization theories6-" for the purpose of reducing drilling cost. Minimum-cost drilling theories rely on a combination of historical data and empirical prediction techniques for selecting optimum bit weight and rotary speed. Past solutions have required extensive use of computing equipment because of both the complexity of the mathematical formulations and the large number of parameters involved. Field attempts to apply these computed results have frequently failed because of the uncertainty of input data requirements. Humble has developed an on-site computer system to control bit weight and rotary speed and thereby implement the concepts of minimum-cost drilling. This system can (1) perform short interval drilling rate tests for formation evaluation, (2) use the results of these tests as input information to solve minimum-cost drilling formulas, and (3) control bit weight and rotary speed in accordance with these computed solutions. The purpose of this paper is to describe the computer control system and present results of initial field testing. Theoretical Considerations Minimum-cost drilling (MCD) requires a quantitative evaluation of the variables involved. Several forms of a basic mathematical model have been sug-gested.'?,' "he relationships reported here form the basis for the solution programmed in this work. Four equations are used, expressing drilling rate, bit bearing wear, bit tooth wear, and cost. A solution for minimum-cost drilling assuming constant bit weight and rotary speed over the entire bit life has been programmed for use in computing MCD schedules. This solution is subject to certain limiting assumptions such as those discussed by Graham et a1.I2: 1. Drilling cost is the summation of bit cost, rotating cost, connection cost and hoisting cost. 2. Diamond bits are excluded. 3. Bit life is limited by either bearing failure or tooth wear, or by a combination of operational factors that make it cheaper to pull an incompletely consumed bit. 4. Circulating hydraulics are adequate and do not limit drilling rate. 5. Bit weight considerations exclude hole deviation. 6. Drilling rate is a function of only bit weight, rotary speed, and degree of tooth dullness; that is, the effects of pressure, lithology, fluid properties hydraulics and drill string dynamics are ignored. In equation form, the four MCD expressions are as follows:

Jan 1, 1970

By Eugene T. Sheridan

The 22d annual survey of the packaged-fuel industry by the Bureau of Mines, United States Department of the Interior, revealed that 26 plants in 8 States were in operation and reported production in 1956. The demand for packaged fuel in the United States has declined gradually since the end of World War II, and the number of operating plants has decreased from 70 in 1946 to 26 in 1956. Annual productive capacity of the industry has decreased also during this period, and the decrease in capacity was about proportional to the decrease in operating plants. Packaged-fuel plants are relatively small, and 85 percent of the active plants in 1956 had an annual capacity of less than 10,000 tons. The same situation prevailed in 1946, when 84 percent of the plants had a capacity of less than 10,000 tons. Total capacity for the 26 active plants in 1956 was 174,600 tons, an average of 6,715 tons per plant. Operating rates in 1956 were the highest since 1951, and the rate of production for the industry averaged 37 percent of capacity.

Jan 1, 1958

By Arthur Matzick

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Jan 1, 1966

By William R. Yernberg

The 2006 North American Tunneling (NAT) Conference was held June 10-15, 2006, in Chicago, IL. The biennial conference was the first NAT conference by the newly formed Underground Construction Association of SME (UCA of SME). The UCA of SME was formed earlier this year at the request of members of the American Underground Association (AUA) (ME, April 2006, page 75). The conference included a keynote session, technical programs, workshops, a trade show and social activities. The conference exceeded expectations with 570 attendees. They included engineers, equipment manufacturers, representatives from government agencies and other interested individuals in the underground construction industry. The trade show was also a success with more than 86 booth spaces sold. Vendors included the biggest names in the underground construction and tunneling industry and included equipment manufactures, construction contractors and engineering companies. The trade exhibition provided a forum for interested parties in the tunneling industry to meet and discuss services, equipment and techniques.

Jan 1, 2006

Geophysical Abstracts 1 - 86 were issued in mimeographed form by the Bureau of Mines; Abstracts 87 - 111 were published in bulletins of the Geological Survey; Abstracts 112 - 120 were issued in mimeographed form by the Bureau of Mines as Information Circulars 7256, 7257; 7267,`7273; 7285, 7292, 7303, 7310, and 7324. 1. GRAVITATIONAL METHODS 7933. Ansel, E. A Eine Untersuchung zum Problem der Isostasie (An Investigation Regarding the Problem of Isostasy). Gerlands Beitr. Geophys., Leipzig, vol. 59, 1942, pp. 16-26.

Jan 1, 1945

By R A. Lynch

The state-of-the-art in cave seismic monitoring is reviewed, with the latest developments in active seismic monitoring included. Seismic monitoring systems are routinely used by most of the world’s block and panel caving mines to track the cave initiation and progression. The current best practice is to use the cloud of seismic event locations as a proxy for cave growth somewhere below. Problems with event location reliability due to seismic ray bending around the (unknown) cave are side-stepped by using sensors installed above the cave. However, the aseismic gap – the (unknown) distance between actual cave back and seismic event cloud – currently hinders reliable estimation of cave geometry.Velocity inversions using the passive seismic data are inexpensive and should be undertaken more routinely. The straight-ray methods should be used with caution, as the underlying assumptions are invalid in caving environments. The double-difference method is more correct for the caving situation, and there have been some promising results published. Constrained geometric inversions make a lot of sense, but have yet to be demonstrated successfully.Two active seismic source have recently been developed for use in the caving environment: a piezoelectric source for ranges up to a few hundred metres and a pneumatically-powered source for ranges up to a kilometre. These sources produce signals on standard mine seismic sensors that can be used to measure seismic velocity variations down to 0.01 per cent resolution. This allows the cave progression to be monitored by measuring tiny changes to seismic velocities as the rock above the cave is fractured and destressed.CITATION:Lynch, R A, 2016. Active and passive seismic monitoring of cave front evolution, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 217–224 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

The Ediacara mineral field is classified as a Mississippi Valley type deposit with stratiform mineralization near the base of the Cambrian beds. Mineral deposition was contemporaneous with sedmentation and reerystallization, and mobilization took place after lithification of the sediments. Several mechanisms of deposition were possible.INTRODUCTIONThe Ediacara mineral field is located in the Mt. James Range approximately 300 miles north of Adelaide, about 12 miles west of Beltana railway siding and 10 miles east of Lake Torrens. It is isolated geographically from similar deposits of equivalent age and environment in the Flinders Range Province (Fig. 1). The climate may be described as semi arid with high summer temperatures and frequent dust storms. Occasional thunder storms are the main source of rain in the summer months.The exact date of discovery is unknown, but is believed to be about middle of the last century. Ulrich (1872) was the first geologist to report on the field. At that time only the southern portion of the field had been prospected (and abandoned). Although the prospects did not appear encouraging Ulrich advised prospecting of the shales and testing beneath the limestone.In 1888, Rosewarne, an Inspector of Mines, visited the Southern Workings and queried whether they were connected with some lode at deeper level or were merely bedded deposits. The first geological map with sections was drawn by H.Y.L. Brown (Brown 1892).Brown recognized three principal rock formations as dolomitic sandstone, kaolinised shales and sandstone, and quartzites and sandstone in descending order. These three basic units are still recognized. He recognized also the stratiform nature of the mineralization in the shales as a...

Jan 1, 1963

By Martin Herrenknecht

After the successful breakthrough at the end of 2006 of both TBMs into the multifunctional site Faido (MFS), in the middle of 2007 the two tunnel boring machines resumed the 12 km long section between Faido and Sedrun. In the roughly a 10 month interval both approximately 465 m long tunnel boring machines were partly dismantled, pushed through the 2.5 km long MFS, rebuilt for the new larger diameter of 9.5 m and reassembled to be ready for operation. In the rebuilding phase, improvements were made to the equipment, especially as a result of experience gained from the previous 14 km long drive in the section Bodio and taking into account the latest information regarding the upcoming 14 km section Faido. Both TBM drives are currently in the rock formations of the Lucomagno gneiss, which stretch over a section of 3.5 km from the MFS Faido to the predicted Piora Syncline. This section is divided into two fold axes of the Chièra Synform, where the Lucomagno gneiss pass from a sub-horizontal into vertical bedding. The drives, with current rock overburdens exceeding 1,500 m and, as known from the excavation phase of the MFS, in part highly disturbed rock formations, are characterized by the locally intense rock squeezing conditions with large convergences in the vicinity of the driving TBM as well as backwards due to the interaction of the two drives. High expenditure for the support measures, reduced driving performances together with extensive extra work associated with deadlines and increased costs are the result. In the paper the previous experience with the TBM drives in the section Faido and the challenges still awaiting us are presented and discussed.