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By F. Maciosek, D. Denton, J. Johnson

Researchers from the Spokane Research Laboratory of the National Institute for Occupational Safety and Health and personnel from Coeur Silver Valley, Wallace, ID, conducted tests using rock strain strips and Split-Set rock bolts instrumented with strain gauges to monitor wall rock strain at the Galena Mine, Osburn, ID. The objective of the test was to identify whether strain on the rock bolts increased prior to a rock burst. Although results were inconclusive, researchers learned that the Split-Set rock bolts yielded in stick-slip fashion in the highly jointed walls of the stope. The bolts were also bent as stress was redistributed following blasting and subsequent movement along joints in the wall rocks.

Jan 1, 2004

Geophysical surveys are currently being carried out over mineral prospects all around the Pacific Rim. Many of these surveys are successful in locating mineralisation in porphyry intrusives, mesothermal environments, and epithermal vein systems. A number of examples of surveys in Indonesia and Papua New Guinea are presented, which show the successful application of various geophysical techniques to the discovery of mineral deposits on the Pacific Rim.

Jan 1, 1999

By V. S. S. Yadavalli, J. Hager, R. Webber-Youngman

"This article investigates the complex problem of a budgeting process for a large mining operation. Strict adherence to budget infers that financial results align with goals. In reality, the budget is not a predetermined entity but emerges as the sum of the enterprise’s operational plans. These are highly interdependent, being influenced by unforeseeable events and operational decision-making.Limitations of stochastic simulations, normally applied in the project environment but not in budgeting, are examined and a model enabling their application is proposed. A better understanding of budget failure in large mines emerges, showing that the budget should be viewed as a probability distribution rather than a single deterministic value.The strength of the model application lies with the combining of stochastic simulation, probability theory, financial budgeting, and practical scheduling to predict budget achievement, reflected as a probability distribution. The principal finding is the interpretation of the risk associated with, and constraints pertaining to, the budget.The model utilizes a four-dimensional (space and time) schedule, linking key drivers through activity-based costing to the budget. It offers a highly expressive account of deduction regarding fund application for budget achievement, emphasizing that ’it is better to be approximately right than precisely wrong’."

Jan 1, 2015

By P. van Meurs, C. van der Poel

From observations of the linear displacement of oil by water from a porous medium as visualized in transparent models, new insight into the mechanism of vircous fingering, as occurring in the case of unfavorable oil-water viscosity ratios, has been obtained. A mathematical description of the observed phenomena leads to formulas. expressing both oil production and pressure drop across the formation as a func-tion of cumulative water injection with the oil-water viscosity ratio as a parameter. Theoretical results are compared with those obtained from scaled laboratory experiments in sand-filled rubes in which water was injected at the one end and production was obtained from the other end. In the second part of the paper the same principles are used to calculate a more realistic production scheme in which production of oil and water is obtained from wells regularly distributed over the field. Results show satisfactory agreement with production data of an actual oil field. Application of the theory is extremely simple as only a limited number of readily available parameters have to be known and results are presented in an analytical form. INTRODUCTION When oil is displaced from a porous medium by water having a viscosity lower than the oil. the oil-water interface is essentially unstable and has the tendency to break up into what are called "fingers" or "streamers". This Viscous fingering has been noted before by Engelberts and Klinkenberg' and has recently been demonstrated in transparent models by van Meurs-. It is highly questionable whether it is at all possible to perform relative permeability measurements In the laboratory reproducing the same distribution of water and oil in the cores as Present in practice. Therefore, we based our descriptive theory on an idealized model which was "tailored" to the fingering mechanism as observed in transparent models under scaled conditions. This approach was the more attractive, as a highly simplified model had already yielded an adequate description of the process. Though we are aware our theoretical approach can be extended in several ways, it is given here in its simplest form to explain the fundamental principles and to avoid complicated formulas. SIMPLEST CASE OF A LINEAR DRIVE Observations and Theoretical Model In Fig. 1 a series of photographs shows how water penetrates into a formation saturated with an oil which is considerably more viscous than the water. The technique for obtaining these photographs, using transparent models, has already been described?. The fingers can be clearly observed and are seen to be mainly parallel to the flow direction. Note that the contours of these fingers are not smooth but show protrusions of water enclosing oil pockets.

By Reda M. Bakeer

"Measurements obtained during load testing of two steel H-piles driven at a site in Northeastern Mississippi are discussed. The general site conditions, equipment used, testing procedures and results of the pile load tests are presented. Both piles were tested in compression and one of the piles was subsequently tested in tension. The piles were instrumented with strain gauges and extensometers to measure the mobilized soil resistance and pile movement. Three different “zero strain” conditions were used to determine the mobilized soil resistance and residual loads due to driving or a load cycle. It was concluded that the effect of residual loads on driven piles could be significant. Driving residual loads influenced the magnitude and distribution of the load transfer curves more than those due to a load cycle. Results of the tension test were impacted by the residual loads from the previous compression test performed on the same pile.INTRODUCTIONSeveral factors affect the performance of a deep foundation system including the subsoil conditions, loading settings, pile type and installation method. Residual stresses develop in piles particularly due to pile driving, but they are typically not accounted for in the analysis (Fellenius 2002). Siegel and McGillivray (2009) presented an assessment of residual loads measured during load testing of instrumented auger-cast-in-place (ACIP) piles. The magnitude and distribution of residual stresses along the pile shaft and toe depend on the pile installation method, previous load cycles and time effects. Poulos (1987) reported that residual load due to driving at the pile toe is independent of pile driving equipment and may significantly affect the results of a pile load test. Hunter and Davisson (1969) reported results of pile load tests performed in compression on fully instrumented piles driven in cohesionless soils along with a discussion of the effects of residual loads. Tension loads of about 445 kN (100 kips) were measured at the pile toe after driving. Unloading residual compression load at the toe was detected as “apparent” tension since the instrumentation was zeroed prior to the test. The researchers suggested a graphical approach to obtain the “corrected” load distribution curves considering that residual load will dissipate following the tension test. Holloway et al. (1975) conducted a study on the effect of residual stresses due to pile driving and developed a computer software that accounts for residual loads. Briaud and Tucker (1984) suggested a method to account for residual loads based on the results of 33 pile load tests performed in mostly cohesionless soils."

Jan 1, 2017

By D. D. Ndenguma

This investigation compares the results from an experimental and numerical study of air flow in a scaled-down underground coal mine model. This was done in order to determine if numerical analysis can be relied upon when searching for ventilation solutions to control high concentration of coal dust and methane gas in underground coal mines. Steady state analyses were used to identify flow patterns and recirculation regions within the mining section while transient state analyses were used to determine the time taken to extract the initial air from the model. The agreement between the experimental and numerical results indicates that numerical modelling is useful in this regard. The study went further to devise a method of determining the optimum position of the jet fan that is responsible for mine-gas dilution at different stages of mining.

Jan 1, 2014

By J. Douglas Causey

In 1984, at the request of Bureau of Land Management, the U.S. Bureau of Mines studied the 13,730-acre Burnt Lodge (MT-065-278) Wilderness Study Area (WSA) in order to evaluate the mineral resources. The WSA is located in Phillips and Valley Counties, MT, about 55 miles south of Malta adjoining the Charles M. Russell National Wildlife Refuge. It is underlain by near horizontal sedimentary beds of the Hell Creek Formation, Fox Hills Sandstone, and Bearpaw Shale. No mines or prospects were found in the WSA. Bentonitic beds were examined, but are generally less than 1 ft thick and, except where exposed, are deeply buried. Kaolin-bearing sandstone in the Colgate Member of the Foxhills Sandstone was sampled and may have potential for use in structural clay products. However, remoteness and inaccessibility of the area make it unlikely that the material could be economically extracted even though some of the material is marginally useful.

Jan 1, 1985

By W. G. Huang

To recover the coal resources of high-sulphur anthracite in Jincheng Mining Area, underground coal gasification (UCG) of No. 15 seam in Fenghuangshan Coal Mine was proposed. The feasibility of the project was confirmed by investigations of occurrence conditions, coal properties, and roof conditions, as well as experimental studies and theoretical analysis. It was found that UCG technology is appropriate to be adopted in the mining of the No. 15 seam, due to the stable rock conditions, simple geological structure and hydrogeology, the high carbon content of the coal, non-cohesiveness, medium-thermal stability, high ash fusion temperature, and weak reactivity with CO2. Further factors are the characteristics of the immediate roof, which consists of 9.11 m of limestone and mudstone with a compact structure and low permeability, and 4.27 m of dominantly mudstone with low permeability.

Jan 1, 2012

By Paul J. Sabatini, Yazen A. Khasawneh

"A Demag CC1800 crawler crane was partially erected on crane mats adjacent to a seawall when settlements near a corner of the crane mat area were observed to be slightly larger than previously assessed. A ground improvement program including installation of dry soil cement mix (DSM) piers was implemented to improve soil bearing capacity. Due to near-surface obstructions, only 75 percent of the DSM piers were installed to the design depth. Because of the partial installation of the DSM piers, an evaluation of the crane pad stability and the effect of the crane loading on the stability of an adjacent 10-ft high concrete seawall, which was believed to have limited (if any) reserve capacity, was required. A two-dimensional finite element model was developed to evaluate the responses of the partially improved ground and the sea wall to the loads imposed by the crane. Geotechnical site investigation and laboratory testing programs were performed to better define the subsurface conditions near the area where settlements occurred and to provide the required mechanical parameters for the soil constitutive model. Analysis results indicate that total and differential settlements of the crane pad and the increase in load on the seawall were tolerable provided limited excavation and replacement of weak dredged soils outside the DSM area would be implemented.INTRODUCTION & BACKGROUNDA Demag CC1800 was erected on 8 ft × 16 ft crane lattice mats at about 12 ft from an existing seawall. Approximately 3.5 in. of subsidence was observed at one corner of the crane mats, while the crane was partially erected and stationary. The approximate location of the crane mats with respect to the existing seawall when the subsidence occurred is shown on Fig. 1.The seawall consists of a reinforced concrete wall connected by reinforced concrete bents to a composite section of sheet pile wall; the total depth of the seawall is about 29 ft. The bents are spaced at about 20’4” and supported by five piles at each bent location. The composite sheet pile consists of concrete and a sheet pile section with a reinforced concrete wale section. The retaining wall is about 10 ft in height and is supported at three levels. The first support level comprises a 2-½” diameter steel rod near the top of the wall spaced at 40’8” the second and third level supports comprise 1-½” diameter steel rods spaced at about 5’6”. The second level support is inclined at about 10 degrees below horizontal and the third level support is oriented horizontally through the wall footing. A schematic of the seawall section is shown on Fig. 2.A geotechnical site investigation was implemented soon after the subsidence was observed. The program included advancing four borings to a depth ranging from 16 ft below ground surface (bgs) to about 30 ft bgs. In general, the investigation showed sandy material (likely fill that was used behind the retaining wall) from the ground surface in two borings located immediately behind the retaining wall. The other two borings furthest from the retaining wall showed very soft to soft clay (possibly dredged material) from the ground surface to a depth of about 10 ft bgs. Based on this information, the ultimate bearing capacity of the subsoils was estimated to range from 1,200 to 2,000 pounds per square feet (psf). From the anticipated crane loading (weight of the crane and loading lifts), a minimum allowable bearing capacity of about 1,500 psf would be required for safe operation. To achieve the required bearing capacity a ground improvement program was selected and implemented."

Jan 1, 2017

By James McKelvey, Larry Drolet, Jason Swartz

INTRODUCTION When divers discovered that sections of a tunnel housing the pipeline that conveys wastewater from the Charleston Peninsula to the Plum Island Wastewater Treatment Facility had caved in, the Charleston Commissioners of Public Works(CPW) moved quickly to determine a long term solution for the city’s collection system, immediately focusing on the Ashley River sewer tunnel along the western boundary of the peninsula. Working with the Charleston community, as well as federal, state, and local officials, CPW developed a fast track yet long life design that can be used as a model for underground construction of tunnels in urban areas. The paper that follows summarizes key aspects of the Ashley River sewer tunnel project. HISTORICAL CHARLESTON Charleston, South Carolina is a culturally significant and historic city that was originally settled in 1670. There are over 100 buildings on the National Register of Historic Places within the Charleston area. Additionally, the first shots of the American Civil War were fired at Fort Sumter in the Charleston Harbor in 1861. As one can imagine, tourism generates significant business for the area with over 1.5 million people visiting Charleston each year. No project, especially one that requires digging, is done within the old city on the Charleston peninsula without careful planning. Many precautions are necessary to prevent damage or disruption to the historical properties. The Ashley River sewer tunnel project is exclusively in the old city. A lot of work was done during the design phase to minimize the impact to historical properties. Some of this work included: an archeological study (where pre-digs were monitored at all shaft sites by an archeologist); a building/structure assessment study (where structures near a shaft site were completely surveyed and cataloged); and an environmental study.

Jan 1, 2005

By Bakker J. de, P. A. Leest, W. L. Dalmijn, H. J. Glass

The test facility at the Delft University of Technology, in the Netherlands, was characterised. Advantages include the possibility of separating particles with high but different densities up to 9 g/cm3, the ease of adjustment to any required separation density and the absence of moving parts. Simultaneous separation of more than two types of particles is possible and the magnetic fluid is safe and convenient to use compared with other heavy liquids. Disadvantages include loss of magnetic fluid with outgoing particles (cost approx US $10/l) and degeneration of fluid due to bacterial activity, reaction with particles and with surroundings. Only non-magnetic materials can be separated, there is limited potential for scaling up and high investment is required on account of the cost of magnets. Future improvements in the design of the apparatus and the properties of the magnetic fluids can only enhance its attractiveness for commercial applications

Jun 18, 1905

By M Donghi, G Ramage, A Barnes

As the mining landscape continues to transform, the challenge of accessing deeper orebodies quickly and safely is becoming a frequent topic of conversation amongst those in the mining industry. The rapid development of underground mine entries to gain earlier access to deeper orebodies is an ever-present challenge to mine owners and contractors. Overcoming this and providing economical solutions to unlock the value in these deeper deposits is a challenge that should be confronted.In 2013, Redpath Australia Pty Ltd (Redpath) commenced construction of what would be the first of two drifts excavated through the use of a tunnel boring machine (TBM) in Queensland’s Bowen Basin.The excavation and development of the two drifts (declines) was completed as part of a contract for underground mining services between Redpath and Anglo American at the Grosvenor Coal Mine Project in Central Queensland, located approximately 5 km north of the town of Moranbah. Having recently completed the drift development, this paper will extend on the early writings of Donnelly, Ramage and Donghi (2014) and provide detail on the operational achievements, advance rates, threats, opportunities and learnings during the excavation of the two declines: the conveyor (CV) drift and the transport (M&M) drift.CITATION:Ramage, G, Donghi, M and Barnes, A, 2016. Experiences gained through tunnel boring machine decline development, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 695–712 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By Robert J. Rothwell

Underground mining of coal by longwall mining methods has not been a predominant technique in Ohio. To date, only five mines in the state utilize this method, however, the technique has sparked a certain amount of controversy. As a mining technique, longwalling was introduced into southeastern Ohio in the early 1970's but it did not attract public attention until the mines began moving into privately held surface lands. This occurred coincidentally at about the same time that the state of Ohio began to regulate the environmental impacts of underground mining. Prior to the passage of the Surface Mining Control and Reclamation Act in 1977, (SMCRA), Ohio's reclamation law, Chapter 1513 Ohio Revised Code (O.R.C. 1513) did not regulate underground coal mines. As a result of SMCRA, the Ohio Statute was amended in 1978, to include regulation of the surface effects of subsidence. The inevitable result was that existing mines were immediately subject to regulations that were not considered during the initial mine planning process. (For an excellent survey of Ohio Laws that deal with coal mine subsidence, see Zima, 1985. ) The problem faced at that time by both the coal industry and the Ohio Division of Reclamation (the agency within ODNR charged with implementing O.R.C. Ch. 1513.1, was that of attempting to superimpose permitting requirements, and design performance standards onto mines that' had been operational for a number of years.

Jan 1, 1986

By J. B. Platt

Many utility fuel choices 1990-95 defied expectations, with utility decisions and coal market developments ever more closely linked. The Central Appalachian coal boom never occurred; clean-enough coal was developed in the hard-hit Midwest; Colorado-Utah coal surged; Pittsburgh seam production strengthened; utilities embraced Powder River Basin coal; and emission allowance prices collapsed. Competition drove productivity gains, but the future is not a simple repeat. Phase 2 brings fewer viable compliance options. Mega-railroad pricing has become a key risk factor -- will this be countermanded by merging utilities and power market competition? Revenue losses from vintage contracts are problematic. Uncertainty also plagues natural gas, in spite of unanimity across major forecasts, since recent experience has been so heavily influenced by the gas bubble.

Feb 24, 1997

The Effect of Mineral Liberation on the Floatabilities of Pyrite, Arsenopyrite and Arsenian Pyrite for Carlin Trend Ores

Sep 13, 2010

By F. Cihangir, A. Kesimal, K. Karaman, B. Ercikdi

Uniaxial compressive strength (UCS) and shear strength parameters(cohesion and angle of internal friction, Cand F) of rocks are important parameters needed for various engineering projects such as tunnelling and slope stability. However, direct determination of these parameters is difficult and requires high-quality core samples for tests. Therefore, this study aimed to explore the applicability of the Brazilian test (BT) - a simple, less sophisticated and inexpensive method for both specimen preparation and testing - to estimate the UCS and shear strength parameters of rocks. Thirty-seven rock types were sampled and tested, 24of which were volcanic, 8 were metamorphic, and 5 were sedimentary. Statistical equations were derived to estimate the UCS and shear strength parameters of rocks using the BT. The validity of the statistically derived equations was confirmed using predictive analytics software (PASW Statistics 18). A strong linear relation was found between BT and UCS values. BT and UCS values exhibited prominent linear correlations withthe cohesion values of rocks. The Mohr envelope was also used to determine the cohesion and friction angle of rocks using BT and UCS values. It is deduced from the current study that the BT values can be used to estimate the UCS and cohesion. However, no relation was observed between the angle of internal friction values and the UCS and BT for all rock types. Therefore, different approaches are suggested for the estimation of the internal angle of friction for application in the preliminary design of projects.

Jan 1, 2015

By J. W. MacDonald

Review of equipment, performance, and shaft design plans including head-frames for sinking and forms for lining are given. Also included are comparative data for shafts of 11 x20 ft and 193/4 x 30 ft with 756 and 666-ft depths, respectively. Advantage from curtain wall installation with "slip forms" which warrant consideration for normal lining are outlined. A preliminary review is also made of "chemical grouting" to stop water inflow leakage with Halliburton equipment and service. Two coal mine shafts recently completed in Franklin County, Ill., afford experience and accomplishment to warrant review. These shafts provide access to a tract with a potential recovery of one hundred million tons. This work provided the initial sinking by other than a contractor's organization since 1918. Four additional shafts required during the interim were sunk under contract arrangement with others. Supervisory contact and inspection afforded experience to govern planning and conduct of the recent work. TEST DRILLING Core test holes were drilled within each of the two shaft locations. Four additional cable tool holes were drilled on a radius of 700 ft from the shaft bottom to determine the coal seam elevations and govern the underground layout plans for each shaft. A graphic log of the hoist shaft test drillhole is shown by Fig. 1. A very soft sandstone was found at a depth of 16 ft. Cored recovery of the sandstone proved much weaker than the overlying compacted sand secured with coring facilities for soil recovery. Gradation from the very soft sandstone to fairly hard material occurred with the next 14 ft, extending to a depth of 30 ft. The weak character within the upper portion entailed need of adequate protection when sinking as described later. A part of the sandstone provided sufficient porosity and permeability to warrant further investigation. Adjacent cable tool drilling for temporary water supply disclosed inflow was limited to 2 gpm with a depth of 40 ft. It was increased to 12 gpm during the next 50 ft of drilling and occasioned subsequent precaution when sinking. General arrangement of facilities for sinking the hoist shaft is shown by Fig. 2. An available steel frame building was used to accommodate the hoist, compressor, shop, and shower or change room. The stiff leg derrick with 90-ft length of boom permitted removal of forms from the wood shop to the storage area or delivery within the shaft. Reinforcing steel and other needs were similarly handled, in addition to headframe erection. The headframe was placed over one end of the shaft to enable passage of forms for lining through the adjacent half next to the stiff leg derrick. The steel headframe as shown by Fig. 3 was fabricated locally. Side anchored cables from the

Jan 1, 1961

By Walter Smith

Environmental Quality Committee ?EQC was created in 1995 to facilitate dialogue between industry and northern communities and help build the understanding of the industry in those communities. ?EQC is made up of representatives from 32 northern communities. ?Meet regularly with Cameco to discuss on going and new projects. ?Tour mine sites on a yearly basis.

Nov 1, 2011

By M. Abdellatif

The Mintek Thermal Magnesium Process (MTMP) process is based on DC open arc metallothermic smelting of calcined dolomite at normal pressure and temperatures of 1650?1750°C. The process was demonstrated at the pilot scale in the period 2000?2004. Major changes to the MTMP pilot plant were made throughout the development period, which lasted for about five years. The changes included design and installation of new equipment, modification of existing equipment, changes in the metallurgical approach in terms of feed rates, feed recipes, furnace operating temperatures, cold and hot dolime feeding, and steady and systematic changes in the operating procedures and maintenance of the plant. As a result, the performance of the pilot plant gradually improved from one campaign to the next, in terms of availability and in particular the condensation efficiency. In Run 10, the process was successfully demonstrated over an 8-day campaign. Keywords Magnesium, condensation efficiency, DC arc furnace, silicothermic reduction.

Jan 1, 2011

By K. H. Coats, M. H. Terhune

Analysis and example applications have been performed to compare the accuracy and computing speed of alternating-direction explicit and implicit procedures (ADEP and ADIP) in numerical solution of reservoir fluid flow problems. ADIP yields significantly greater accuracy and requires about 60 per cent more computing time than ADEP, not 300 or 500 per cent more as reported elsewhere. l,2 INTRODUCTION Several recent papers 1-3 discuss an alternating-direction explicit difference approximation (ADEP) to the diffusion equation. Example applications of ADEP and ADIP4 were reported to support conclusions that ADEP is comparable in accuracy to ADIP and requires one-fifth to one-third the computing time of ADIP. Applications of ADEP in calculation of two-phase flow in reservoirs was also proposed. 3 This study was performed to compare further the relative merits of ADEP and ADIP in simulation of two-dimensional flow of one and two fluid phases in reservoirs. Since two-phase flow equations are often essentially elliptic rather than parabolic, the efficiency of ADEP in solving the elliptic equation was also examined.

Jan 1, 1967