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By J. Janin, J. F. Bougard

Development of improved transportation networks in major urban centers has led more and more to underground construction, the only reasonable solution for decreasing surface traffic congestion. Excavations required by these projects usually cause decompression of the surrounding soil mass which results in subsidence of several centimeters. While these magnitudes of subsidence have no consequences in undeveloped areas, they are often unacceptable in urban areas where existing buildings, structures and utilities are endangered. Recent tunneling projects for the extension of the Paris Metropolitan Transit System (R.A.T.P.) underground network were carried out with this in view and gave rise to the development of a number of innovative techniques for minimizing ground decompression and subsidence. As shown in Figure 1, the recent R.A.T.P. expansion program includes a new express metro, 46 km long, crossing Paris from East to West, and the extension of many existing metro lines in the suburbs. From the start, R.A.T.P. was faced with many unique technical problems for which there was little precedent experience. The structures to be built have large dimensions, with cross-sections typically ranging from 40 to 300 m2, and exceptionally to 600 m2. The new lines are often very deep because the shallow profile is already congested by the existing metro, interceptors, sewers and a very large number of utilities. As a result, new construction is often below ground water level by as much as 20 m. Moreover, the geology varies widely from hard limestone with compressive strength over 1500 kg/cm2 to inconsistent water bearing sand. Finally, curves in the East-West line must have a minimum radius of 500 m which frequently forces the alignment to pass below existing structures, buildings and monuments.

Jan 1, 1974

By J. Searra, M. Aboagye

"For new mining projects or for medium- to long-term areas of existing mines, drilling data is invariably on a relatively large grid. Direct estimates for selective mining units (SMUs), and also for much larger block units, will then be smoothed due to the information effects and the high error variance.The difficulty is that ultimately, during mining, selection will be done on the basis of SMUs on the final close-spaced data grid (grade control), which will then be available, i.e. the actual selection will be more efficient, with fewer misclassifications. However, this ultimate mining position is unknown at the project feasibility stage and therefore has to be estimated. This estimation is required because any cash flow calculations made on the basis of the smoothed estimates will obviously misrepresent the overall economic value of the project, i.e. the average grade of blocks above cut-off will be underestimated and the tonnage overestimated for cut-off grades below the average grade of the orebody. Similarly, unsmoothed estimates will be conditionally biased and will give even worse results, particularly in local areas of short- and medium-term planning or mining.This paper presents a case study of indirect post-processing and proportional modelling of recoverable resources designed for mediumand long-term mine planning at the Gold Fields’ Tarkwa Mine in Ghana. The case study compares long-term indirect recoverable mineral resource estimates based on typical widely spaced feasibility data to the corresponding production grade control model as well as the mine production. The paper also proposes certain critical regression slope and kriging efficiency control limits to avoid inefficient medium- to longterm recoverable estimates, and highlights the danger of accepting block estimates that have a slope of regression less than 0.5."

Jan 1, 2015

As mining operations in the United States (US) have become more productive, controlling the dust exposure of mine workers has become more challenging. In response, US mining operations are applying basic controls at elevated levels and are looking to emerging control tech­nologies in an effort to better control airborne respirable dust levels. The Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health (NIOSH) conducts research to develop and/or improve control technologies that reduce the respirable dust exposure of workers in underground coal mines. The goals of this research involve optimizing the use of water sprays and ventilating air, as well as, evaluating emerging control tech­nologies. An overview of dust controls typically utilized in underground US coal mines will be provided. An update on ongoing PRL research efforts that are evaluating new control technologies will also be presented.

Jan 1, 2008

By R. D. Dukimo, M. V. Sevian

The nature of fracture and factors that control the extent of fracture in the tumble-drum and drop-tower tests have been identified. The product-size distribution, on which the standard strength indices for these tests are based, and the breakage rate constants depend on a number of factors other than the strength of the lumps. The standard indices and rate constants are meaningful only in a comparative context and for events whose loading mechanism is similar. The results of experiments on three Australian ores, from Yandi, Koolan and Mount Whaleback, are used in combination with fracture mechanics theory to explain why different tumble-drum standards have been found to be fully consistent. A more meaningful measure of strength could be the parameters of the Weibull function, scatter and average strength

Jun 19, 1905

By Tyler R. J

Methylene blue dye adsorbs on chalcopyrite concentrates slurried in aqueous solution. Saturation adsorption can be achieved within about 24 hours for dye equilibrium concentrations greater than about 10-5 M. The dsorption coverage is obtained from a measurement of the' colour change of the solution. Comparison with BET measurement of the concentrate surface area shows that 2.4 ± 0.1 µmol of methylene blue are adsorbed per square metre of surface accessible to the dye cation. The procedure described can be used as a single-point measurement and values for the surface area can be otained to within about 10 per cent with inexpensive instrumentation.

Jan 1, 1979

By David Dardick

Tround International Inc. is developing rock excavation and drilling devices which utilize a simple patented mechanism for firing frangible projectiles. This system launches a salvo of three projectiles with every shot in automatic sequence. Studies conducted by Physics International Inc. have demonstrated that firing projectiles into hard rock such as granite creates fragmentation which is much faster and cheaper than conventional drilling and blasting. The Tround salvo approach enhances this further by a controlled stresswave interaction created by a slight time difference during impact of the individual projectiles. The University of Maryland is conducting additional studies to optimize these parameters.

Jan 1, 1981

By Todd M. Ruff

This report summarizes ongoing research at the National Institute for Occupational Safety and Health, Spokane Research Laboratory, in which collision warning systems for surface mining dump trucks are being evaluated. Common accidents involve these large trucks running over smaller vehicles or pedestrian workers. Collision warning systems currently use one of several methods, including radar, radio-frequency-signal detection, or ultrasonic signals, to detect and warn of the presence of an object or person in the blind spots of the mining equipment. Most available systems have not been tested on large off-highway dump trucks. This report evaluates several systems on two sizes of trucks, a 50-ton-capacity truck commonly used in quarries and construction and a 240-ton-capacity truck commonly used in open-pit mines. Tests were conducted to determine false alarm rates, alarm effectiveness, and reliable detection zones for a person and a pickup truck. The results indicate that radar and radio-frequency identification systems show promise for this application and that several of the improved systems are ready for extensive field tests. However, challenges still exist in applying these technologies to large trucks.

Jan 11, 2000

By Howard W. Wainwright

This bibliography was compiled by the Bureau of Mines as part of an investigation into the possible utilization of low-temperature coal-tar bases. The bibliography consists of literature and patent references from about 1945 to 1961 and is divided into the following headings: Analysis and Composition; Production, Synthesis, Reactions, and Utilization; and Separation, Purification, and Properties. Although over 1,000 references are included, no attempt was made to insure a comprehensive survey. The literature and patent references are arranged alphabetically by author or patentee. When several publications have the same author they are listed in reverse order of age, with the newest first. An author index is included because secondary authors are not cross-indexed. In almost every instance, the entry is accompanied by a Chemical Abstracts reference for those interested in locating an abstract of the original paper.

Jan 1, 1962

By D Prior

The Australian mining industry is a significant contributor to the nation’s greenhouse gas (GHG) emissions, and like any industry, it must make efforts to reduce these. Medium- and long-term strategies will include the replacement of diesel engines with alternative energy sources, but what can be done in the short-term to reduce diesel consumption and hence CO2 emissions? Haul trucks are identified as the major contributors of CO2 emissions in the mining fleet and this paper focuses on firstly identifying what drives haul truck emissions and secondly, discussing what is the role of the Fleet Management System (FMS) in reducing these. A key enabler of this is having a robust fuel consumption model within the FMS, and I describe how this may be done. Besides novel approaches to incorporating fuel consumption (CO2) management into truck assignment algorithms, this paper also describes how the FMS can be used to implement and manage procedures and policies to reduce haul truck emissions.

Jun 22, 2022

By J Geronimo, P Kumar, Z Yussupova, M Yahyaei, M Powell

This work goes beyond the general perception of how the well-known mine to mill process can be applied, by applying deeper knowledge along the mining chain. Grade deportment and dilution are considered at the mining stage, and modelled with the new SMI blast movement simulator, linking with the block model data. Assessing the shift to a considerably more competent section of the orebody is quantified via substantial milling trials at standard and higher-intensity blasts. These were stockpiled for batch processing through the mill to ensure feed integrity. The trial work included operating the mill at widely different fillings to develop Grindcurve milling responses. Additionally, model informed process control is initiated via a mill prediction tool.It has been found that accounting for blast movement for the higher intensity blasts could generate additional value of around $1.5M per blast. With the high-intensity blast and changing mill control, the plant was easily able to exceed projected mill throughputs with the far more competent Pipeline ore. Strategies to shift the workload and debottleneck the milling circuit were proposed and proven during the milling trials, demonstrating an increase in throughput of 7 per cent despite running at a lower SAG mill speed, and potential of 16 per cent for increasing the SAG mill to standard operating speed. A number of process improvement opportunities have been identified to enhance current productivity and ensure long term capability to process the considerably more competent future ores. All of this is being linked in with the major digitisation program at the Barrick Cortez site, with an objective of linking all the data into a mine-wide process optimisation system, that can embed the processes by providing process-wide data access and production support via the future dynamic models linking ore body knowledge to productivity along the full process chain.CITATION:Powell, M, Yahyaei, M, Geronimo, J, Yussupova, Z and Kumar, P, 2018. The designed approach to mill liner optimisation – experience at Pustynnoye mine, Kazakhstan, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 595–612 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By K. K. Kelley

The entropy values at 298.1° K. for the elements and inorganic compounds, on which sufficient data were available for calculation in 1931, were discussed in a previous publication (96).3 Since that time the specific beats at low' temperatures of many more inorganic substances have been determined, and considerable advances have been made in the realms of spectroscopy applicable to the determination of thermodynamic properties. Moreover, a critical study of the existing vapor-pressure data made by the author (98) furnishes entropy of vaporization results suitable for obtaining approximate values of the entropies of a number of gases from the entropies of the solids or liquids. Consequently, it appears worth while at the present time to supplement the former publication, giving the new values now obtainable and making such revision in the older values as the data warrant. The methods of calculating entropies were discussed in previous publications (96, 98) and will not be repeated here. ENTROPIES AT 298.1° K. FOR INORGANIC SUBSTANCES In the following pages, the same arrangement is followed as in the previous publication (96). All entropy values are expressed in 15° gram-calories per degree Kelvin per gram-formula mass of substance. The figures given for gases do not include the effect of nuclear spin, as is nearly universally customary at present. The estimates of accuracy in the case of the values obtained from heat-capacity data apply only to the existing measurements and to the necessary extrapolations as they are made. It is assumed usually that the substances are in such an energy condition at the lowest temperatures reached in the specific-heat measurements that the usual normal type of extrapolation may be made. No allowance is made for error in this assumption. The recent work on Gd2SO4. 8H2O and FeC13 illustrates the difficulties that may arise in obtaining the entropies of some paramagnetic substances. Also the data and calculations for such substances as CO, H20, and N20 show that the correct entropy is not obtained in all cases by indiscriminate application of the usual

Jan 1, 1936

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

By E. C. Lane

[This is the tenth in a series of retorts on properties of commercial motor fuels, made in accordance with a cooperative agreement between the Cooperative Fuel Research (C.F.R.) Committee e end the Bureau of Mines of the United States Department of the Interior. The first report rave data on motor gasolines sold during .e winter of 1935-36.3/ The present report presents analytical data for 1,732 samples, representing the products of approximately 50 companies, which, as in previous surveys, include both lame and stall suppliers. In addition, the Pacific coast is represented by data that were averaged by the Pacific Coast Technical Group before being submitted and are published exactly as they were received. As in previous surveys, the data are divided into the three groups of samples of regular-price, premium-price, and third-grade gasolines, and each group has been averaged separately. he number of samples, items, and brands comprising each groan), exclusive of those of the Pacific coast, are as follows: Regular price, 934 samples, 230 items, and 50 brands; premium price, 465 saris samples, 184 items, 40 brands; third-grade gasolines, 360 samples, 177 items, and of these terms as used in the surveys are follows: Sample: The individual supply of gasoline obtained at the filling station and analyzed in the laboratory.]

Jan 1, 1941

Jan 1, 1967

Using a series-model of an automotive short range radar sensor (SRR) and a recently completed experimental radar system, field tests have been performed in a surface mine. It was examined, to what extent low-cost electronically scanning radar sensors can provide useful data for assistance systems on large scale mining machines. Simple sensors are useful for anti-collision safety zones or hopper car automation. The more complex and sophisticated experimental radar system using digital beam-forming can clearly detect and map the contours of trenches and slopes. The overall promising results refer to many more potential applications for electronically scanning radar in surface and underground mining as a reliable alternative to mechanical laser scanners.

Jan 1, 2007

By R. L. J. Phillips

"The environmental impact of the Rabbit Lake project is presented. Baseline data for fish, water, air and radon collected in 1973, 1975, 1980and 1986, are compared with post-development environmental monitoring data. Predicted environmental impacts for the developed Rabbit Lake and B-zone deposits are compared to the actual impacts. INTRODUCTIONThe environmental impact of the Rabbit Lake project has been documented through the years in several submissions to the government agencies. In 1972, the environmental baseline study for the Rabbit Lake area was completed prior to any mining activity at the Rabbit Lake pit (Fig. 1).Sampling concentrated on Hidden Bay and Pow Bay, which received the treated effluent and the waters drained from Rabbit Lake respectively.A second baseline study was done on the Collins Bay area in 1980(Fig. I) in preparation for the mining of the B-zone pit. The detail in this study was considerably greater than the detail in the previous study. Collins Bay and Harrison Peninsula were the areas sampled. The B-zone deposit is being mined at present.With the discovery of the A-zone, D-zone and Eagle Point deposits, it was decided in 1986 to begin proceedings to obtain approval from Saskatchewan's Department of the Environment, and from the Atomic Energy Control Board to develop these deposits.In preparation, a third baseline study of both the Rabbit Lake and Collins Bay areas was done in 1986 and 1987. The emphasis was to establish the baseline at the three new deposits, to quantify the actual impacts of the existing Rabbit Lake operations and to confirm the Collins Bay B-zone (1980) impact predictions. The new deposits will allow us to continue to produce uranium into the future. In January 1988, Saskatchewan approval was received.Since 1975 in the Rabbit Lake area and 1980 in the Collins Bay area, routine environmental monitoring has been done. This has resulted in one of the largest and most comprehensive environmental data bases in North America in mining. By the time the Eagle Point deposit is mined to completion, there will have been data collected for approximately 40 years.Further discussions follow which describe the impacts of the past (1972 to 1984), the present (1985 to 1987) and the future. In addition, the past and present performances and the future plans of the .waste management systems will be discussed."

Jan 1, 1989

By Michael Gauna

An evaluation and analysis of a coal pillar bump in a West Virginia mine indicated that the pillar bump occurred because of the unique combination of controlling factors. The pillar?s development stability factor of 2.6, based on Mark-Bieniawski strength and tributary loading, would typically indicate an adequate pillar size for long-term main entries. A combination of multiple-seam mining geometry and geological conditions resulted in stress concentration leading to the coal pillar bump. No high extraction mining had been performed in the area and the overlying works appeared to have adequate stability factors. However, it was interpreted that long-term flooding had softened the overlying pillar system and rendered all but the largest pillars ineffective. Contributing factors include large overlying pillars transmitting stress through the approximately 60 ft of interburden and the failed pillar?s location at a transition in the immediate roof from shale to hard, massive sandstone. Other contributing factors include sandstone channeling forcing the development section to mine the pillar smaller than surrounding pillars in an attempt to avoid the channel, the relatively high overburden of 1,100 ft, and the pillar?s position in the bottom of a trough within the coal horizon. Pillars subjected to similar conditions on the other side of the section did not fail where the roof was composed of shale, even though the roof exhibited evidence of high stress concentration. An analysis was undertaken to determine appropriate pillar size for future mining. The conditions were evaluated by investigating mine historical conditions, assessing pillar bearing pressures, and using Lamodel 2D coupled with traditional Mark-Bieniawski pillar strength and tributary area loading stability factors to determine the stress levels for the pillar. Recommendations for future pillar sizes were based on the critical load bearing capacity identified by the analysis. To date, no further pillar bumps have occurred.

Jan 1, 2008

By C. F. Gleeson, D. G. Sheehan

"The results of humus and overburden geochemical surveys over the Doyon, Bousquet and Page-Williams gold ore deposits are presented.These studies show that humus sampling for gold gives negative results over the Doyon deposit. The lack of response is probably caused by the presence of 1 m of relatively impermeable glaciolacustrine clay and silt that overlies 1 m to 2 m of till over the surface expression of the ore zone. By contrast, positive responses for gold occur in humus samples over the Page Williams A and C gold deposits. The ""A"" ore zone is covered by several metres of exotic calcareous till over 0.5 m to 1 m of older, locally derived till. Anomalous values for gold in humus range from 10 to 35 ppb over the orebody. Overburden over the ""C"" ore zones is much thinner, generally it consists of less than 2 m of sandy till. Trenching humus anomalies that range from 10 to 1360ppb Au uncovered the gold mineralization. The geochemical dispersal trains in till from the Doyon orebody and the Page-Williams ""A"" zone are relatively short (i.e. less than 200 m) because both deposits occur in the lee of bedrock highs that shielded them from extensive glacial quarrying. Dispersal trains from all three pyritic gold deposits can be defined using either the fine fraction or heavy mineral fraction of the till.The intensity of the gold in till anomalies over the ore zones is variable. Therefore, it would be misleading to attach rigid significant threshold gold values to overburden drilling results. Each case must be evaluated based on bedrock topography, sample density, overburden type, thickness of till, as well as size, type and orientation of the target exposed to glacial erosion."

Jan 1, 1987

By John A. Johnson

For the purpose of comparing the amounts of dust produced by various mining operations, samples of atmospheric dust were collected during a complete cycle of drilling, blasting and mucking at or near the face of the Bureau's Mount Weather testing adit while the efficiency of several types of stemming in metal-mine blasting was being investigated. ACKNOWLEDGMENTS All gas samples were analyzed in the laboratory of the Bureau of Mines Gas Section at Pittsburgh, Pa.

Jan 1, 1939

By Paul Doherty

Expansion of the global piling industry has been coupled with significant research efforts investigating the mechanisms controlling pile capacity. Static pile design has transitioned from total stress approaches toward effective stress design, with associated improvements in predicting pile performance. As a result, the available literature is heavily skewed toward static capacity prediction. However, when considering piles offshore, the majority of loading is not static but highly variable and cyclic in nature. This paper outlines the additional factors that require consideration for cyclic pile design, including elevated loading rates, cyclic displacements and capacity degradation. A review of the literature identified a number of cyclic pile testing programs which are collated in this paper. General trends are established through comparison of the tests within the database and the conditions where cyclic loading is most likely to be a concern are identified. In particular, loading conditions which involve full plastic shear reversals are seen to cause the most extreme cyclic damage, with the degraded capacity as low as 31% of the precyclic static capacity. The underlying mechanisms which can result in cyclic damage are explored, with particular attention given to the pore pressure response, radial stresses, shear transfer and particle reorientation.

Jan 1, 2009