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By S. M. Marshall

The investigations recorded in this bulletin were conducted by the Pacific Coke & Coal Co. in cooperation with the United States Bureau of Mines and the University of Washington. They cover one phase of a comprehensive investigation to determine whether coals from an extensive, undeveloped area of Pierce County, Wash., can be used in the manufacture of coke for the iron blast furnace. The completed investigation had three parts: (1) A geological survey of the coal property, (2) washing and crushing tests of the coals, and (3) coking and by-product tests. The geological survey, which was not conducted in cooperation with the Bureau of Mines and the University of Washington, included systematic tracing of the coal beds by test holes throughout the property, except some portions covered by an impenetrable layer of glacial drift. By this means all of the beds were correlated, their thickness and general character were determined, and tonnage estimates were made. Only such parts of the survey results as are necessary to a full explanation of the investigations described herein are included in this bulletin.

Jan 1, 1931

By K. Barani, F. Moradpouri, M. Godarzi

A sampling campaign carried out on the lead flotation circuit at Lakan lead-zinc processing plant demonstrated that the Pb recovery was only about 68-69%. Characterization of the Pb flotation tailing showed that 61.4% of the Pb is in the –37 μm size fraction, which is difficult to recover by flotation. Batch flotation experiments were carried out on a plant sample of the lead flotation feed and high-intensity conditioning (HIC) was used to improve flotation recovery. The results showed that increasing the collector conditioning time from 1 to 3 minutes significantly increases the Pb recovery from 42.5% to 57.3%. Further increases in conditioning time to 5 to 7 minutes decreased the Pb recovery. With a collector conditioning time of more than 3 minutes, due to the surface cleaning effect, increasing collector and frother dosage improved the flotation selectivity and recovery, even at higher collector dosages. The Pb recovery increased from 69.1% to 79.8% with increasing impeller speed from 600 to 1250 r/min. HIC increases the flotation kinetics and greatly improves the flotation recovery and concentrate grade.

Apr 2, 2022

By J. Koster

[In 1178 thn S-00n of thr !~Viluralcal Divicion, pur--'11 cf Mines, bcran an o. 't iv in': n-t!Y_Vnn of vothod; for recoverin'-1, Achol, copp~r, nK precioun notnin Zycn o;. -z of tic Bunkcrvillo KOH& in Clark County, Tcv. Tho Bunkcrvillo ran arc of t,-j)(,e of -iincrilization similar to that of 02 SWbury, Ontario, CannO, nichvl dc-?o?-:.t,. At prcoont, only n anall tonnes? p of ore has loan cxDr)scd in t*ic' :hui:er7ilIp rc: inn, ann. there is decided nce! for orjn: izod OrospectiAg ina drvclo-nnnt "crk there. It wann believod, howevar, t4it the dc,cuits varo 3ilficUntly siSnIficant to warrant an investigation iito their]

Jan 1, 1939

By C. W. Owings

"Coal may be and has been hauled safely at approximately the same cost with permissible2 storage-battery locomotives as with trolley, cable-reel, crab-reel, or nonpermissible storage-battery locomotives. While in general, thinking mining men readily admit the relative safety of the permissible storage-battery locomotive there are some persons who question the safety of this type; however, the greatest opposition to the widespread use of storage-battery locomotives is from those who believe them to be more expensive to operate and to be more expensive in first cost than the trolley or cable-reel locomotive. Data collected during a comprehensive study- of storage-battery and wired transmission of power in some Pennsylvania and West Virginia coal mines indicate that there is but little difference between the cost of hauling with cable-reel or with storage-battery locomotives. It would appear that if this fact were mere generally known mine operators of the more progressive type would install such equipment and avail themselves of greater safety in hauling coal.The need for greater safety in haulage in coal mines is readily understood when it is considered that during the 12 month period, July 1, 1929 to June 30, 1930, trolley or cable reel gathering locomotives caused four explosions in which 407 lives were endangered, 11 persons were injured, and 30 lives were lost. Still another disaster was averted by the vigilance of a fire boss, who discovered a stratum of gas 3 feet thick at the top of an entry into which a gathering locomotive was about to enter. Other explosions not resulting in any fatality probably have not been reported. In addition numerous fires have been caused by trolley or cable-reel locomotives, and these fires probably would have been avoided had permissible storage-battery locomotives been used."

Nov 1, 1930

The extremely cold weather and heavy snowstorms of January and February in northeastern Pennsylvania--with frozen mining equipment, diminished preparation and lack of railroad cars--severely hampered the production and distribution of anthracite. As a result, the previous estimates for the 2 months have been revised. On March 1, 1977, at the Porter Tunnel of the Kocher Coal Company at Tower City, Pa., an underground flash flood, which apparently broke through the wall of an adjoining abandoned shaft, swept through the mine. As of March 9, 1977, four miners were reported killed, three injured, and five trapped in the wreckage. The Kocher Coal Company began operations at the Porter Tunnel in 1968 and has had no fatalities until this current tragedy. The mine employs 20 persons on the surface and 115 miners underground, producing 750 tons of coal per day. Of the 109 underground mining operations in the anthracite region, this is the one remaining large mine that employs over 100 men.

Jan 1, 1977

By Zhibiao Guo, Jinglin You, Dongshan Yang, Yuanxin Zhao, Yuhui Li, Jingwei Gao

By utilizing collapsed gangue to create gob ribs, roof cutting and roadway maintenance (RCRM) technology enables coal pillar-free mining, presenting a novel approach. Due to their inherent structure, faults, which are common geological formations, can lead to various hazards, including fault sliding and significant deformation of roadways. In this study, a selfdesigned underground engineering simulation test device is utilized to imitate the cross-fault mining of the 11,101 working face in the Qipanjing Coal Mine (East). The objective is to examine the behavior of the surrounding rock and stress evolution. Generally, the experimental findings demonstrate that compared to the return air roadway, the RCRM roadway experiences a 3.3% decrease in maximum coal rib stress. This suggests that the implementation of this technique can effectively alleviate the stress on the surrounding rock of the roadway. The maximum coal rib stress, lateral pressure of the gob rib, and maximum deformation of the roof near the fault of the RCRM roadway are 11.3%, 25.6%, and 86.1% greater than those of the conventional geological conditions, respectively. The roadway deformation is negatively impacted by the fault structure. Based on experimental data and field measurements, a discrepancy in the maximum roof deformation between the test and field monitoring results under typical geological conditions is 8%. This indicates a favorable alignment between the test results and the real-life scenario. In conclusion, the proposed targeted control technique is implemented in the field by integrating the mining invariant equation and gangue volume expansion equation. This not only validates the effectiveness of the technology but also offers valuable insights for the future utilization of RCRM technology under comparable circumstances.

Feb 20, 2024

By Robert F. Kehrman

As part of the Bureau of Mines research on the In-Situ Uranium Leaching, various geophysical resistivity measuring techniques were -evaluated to identify a rapid reliable method for detecting the underground migration of lixiviant outside of the planned limits. Surface and downhole galvanic resistivity and controlled source audio-magnetotelluric (AMT) methods were tested at an in-situ uranium mine in Northern Wyoming during start-up of a new mining area. Downhole galvanic and AMT were the most promising techniques.

Jan 1, 1980

By D Miller, M Dowling, R Domotor

"This paper is focused on blasting activities undertaken as part of the Pacific Highway Upgrade – Tintenbar to Ewingsdale – project (T2E). This is a ‘priority 1’ Pacific Highway road construction project in New South Wales (NSW), to be completed by mid-2015 (weather permitting). T2E will provide approximately 17 km of dual carriageway road starting at the northern end of the Ballina bypass and extending to the Ewingsdale interchange, and will complete the existing dual carriageway road between Ballina and the NSW/Queensland border.Roads and Maritime Services (RMS) (formerly the Roads and Traffic Authority) is delivering the project on behalf of the NSW state and federal governments. In October 2011, RMS awarded a contract to Baulderstone Pty Ltd (now Lend Lease Engineering Pty Ltd – Lend Lease) to design and construct T2E. One of the key elements in this project is the St Helena Tunnel.In order to avoid the steep grades of St Helena Hill, eliminate a well-known accident black spot and maintain the aesthetics of the Byron hinterland escarpment, RMS and Lend Lease prepared designs to construct a 434 m long dual carriageway tunnel, 46 m below the ridge line of St Helena Hill. Lend Lease elected, where geotechnical conditions permitted, to use drill and blast methods to excavate the full tunnel profile, instead of traditional mechanical excavation techniques.Since all blasting locations (both inside and outside the tunnel) were in close proximity to nearby residents, the NSW Department of Planning and Infrastructure imposed strict air blast overpressure (airblast), ground vibration (vibration) limits and limited working hours. Both RMS and Lend Lease recognised that these restrictions meant that nearby residents may be exposed to blasting activities for longer than was necessary. As a result, after close consultation and agreement with the nearby residents, RMS applied successfully to the NSW Department of Planning to increase the airblast and vibration limits, as well as the working hours.Working under these new conditions, Lend Lease employed a range of best practice drill and blast technologies provided by both Orica Australia Pty Ltd and Atlas Copco Mining and Rock Excavation to improve the safety and efficiency of blasting activities and to minimise the potential negative impacts of the blasting works on affected residents. These technologies included: the use of a continuous environmental monitoring system to record the results of the blast events and provide quick and easy reporting to key stakeholders to address RMS specification requirements electronic detonators to enable accurate hole detonation timing for vibration compliance and to give project engineers the flexibility and precision to alter each design to suit the geological profile of each face the use of two software programs and advanced drill rigs to enable the efficient design of blasts, electronic transfer of designs to the drill rigs, as well as in-hole monitoring and recording of drilling performance the use of a specialised bulk emulsion system to deliver fully coupled bulk explosives into face blastholes to maximise fragmentation, and decoupled bulk explosives into perimeter blastholes, to reduce overbreak and deliver a cleaner profile.By taking a progressive approach towards the environmental restrictions and the work hours imposed, as well as utilising best practice blasting techniques, RMS and Lend Lease were able to blast with confidence and achieve their production deadlines and reduce the total cost of the project.Most importantly, RMS and Lend Lease were able to meet their environmental obligations and work constructively with the nearby residents to ensure that the blasting was undertaken as safely and efficiently as possible without delay or negative impact.CITATION:Dowling, M, Domotor, R and Miller, D, 2014. Improving excavation efficiency at the St Helena Tunnel using best practice drill and blast techniques, in Proceedings 15"

Sep 17, 2014

By A. N. Fried

One of the important problems confronting oil producers in appraising the possibilities of secondary recovery in many California fields is the effect of viscosity on oil recovery by water flooding. In January 1954 there were 554 fields and/or pools, in the State, that produced 1 million barrels daily, and 138 of these pools produced approximately 267 thousand barrels daily of heavy crude oil having gravities below 200 API. Many of these fields are nearing the end of their primary economic life and still have high residual-oil saturations, a favorable factor in water flooding. The crux of the problem is whether or not enough oil can be recovered from these fields by water flooding to make the operation economically successful. Some experiments on the relationship between viscosity and oil recovery have been made by other investigators, but in most instances the viscosity of the oils used in the experiments was lower than the viscosity of the oils found in many of the heavy-oil fields in California. A study was undertaken, therefore, to determine the relationship between oil viscosity and recovery over a wider range of viscosities and to compare the experimental results with those predicted by theoretical calculations.

Jan 1, 1955

By H. Harzer

Statistics Canada record s indicate that in recent years 70 to 80% of the entire Canadian coal production originated from Western Canadian mines, in which about 55 to 65% of the coals are bituminous. Until recently, less than 20% of the latter were extracted by underground methods , the remainder being surface-mined. However, it is estimated that within the foreseeable future up to 80 or 90% will have to be gained by underground techniques. Although Western Canadian coal resources are considerable, they are unfortunately locked in severely distorted, steeply pitching and faulted seams of variable thickness. Consequently, their economic extraction poses serious engineering problems. One possible solution to the problems is to apply hydromechanical methods to underground mining. This is a well-proven method shown to be economically viable under Western Canadian conditions. This paper endeavours to widen the scope of published data on hydraulic coal mining and is based on practical engineering and cost data gathered through contacts with West German designers and operators of hydraulic mines.

Jan 1, 1978

The original manuscript of section 2 of this series of miners' circulars devoted to accident prevention in bituminous-coal mines was completed in September 1944. At that time roof bolting had been tried with some success in the lead-mining district of south-eastern Missouri, but information on the subject was so fragmentary that it was not included as a method of roof support. References to roof support in bituminous-coal mines, therefore, were confined almost entirely to conventional timbering methods. In 1947 the Bureau instituted a research program and intensive study of the general problem of roof control, which emphasized roof-bolt application. The rapid increase in mechanized mining following the close of World War II provided the impetus for the Bureau's roof-control investigations, because the vertical supports used with conventional timber restricted the maneuverability of mechanical face equipment, and the industry wanted to explore every possible method of eliminating interference with the production cycle to gain full advantage of mechanized mining. Moreover, the accidental dislodgment of vertical supports greatly increased the roof-fall hazard. As roof falls have killed and seriously injured more mine workmen every year than any other cause or classification of injury since records have been kept, the Bureau assumed this investigative leadership with the prime objective of substantially reducing the annual toll from falls of roof, including falls of rib and face.

Jan 1, 1958

By R. T. Johansen

A gradual decrease in injection rates commonly occurs as a water-flooding project becomes older. This decrease can be attributed to changes in reservoir conditions, such as swelling of clay minerals, fillup, or gradual plugging of the sand face. However, a rapid decrease in the rate of injection indicates abnormal behavior and is cause for alarm. Extreme plugging conditions can completely stop injections into a formation. Such behavior in wells was the main concern of the tests described in this report. An accepted method of alleviating this condition is by backflowing input wells - closing the supply lines to the wells and allowing the reservoir pressure to force water back into the wellbore and to the surface. If backflowing is not successful, a string of smaller diameter pipe sometimes is run inside the casing, and the sand face is flushed with a waterspray. More drastic treatment is to inject acid into the wellbore to dissolve extraneous matter, or even part of the reservoir material, in an attempt to restore the permeability of the sand immediately around the wellbore. Any of these procedures can he coordinated with bailing and swabbing of the well for cleanout purposes.

Jan 1, 1957

By Manuel Gomez

This report presents prediction equations for 12 variables that are indicative of metallurgical coal quality. The variables include six for coke strength and six for carbonization product yields. All variables were predicted for coking coals having volatile matter contents from 16.3 to 42.1 percent, dry basis. The prediction equations, developed by mathematical-statistical techniques, were based on information from the proximate and ultimate analyses, the size consist, and the petrographic composition of bituminous coals carbonized in BM-AGA retorts at 800°, 900°, and 1,000° C. The equations were evaluated for validity with independent data derived from the 900° C carbonization of 33 binary blends of various coals and 22 binary blends of Pocahontas No. 3 low-volatile bituminous coal with 11 high-volatile bituminous coals. Results show that metallurgical coal quality can be predicted ahead of mining because data used to derive the prediction equations can be obtained at the time of exploration. Capability to forecast coal quality is useful in mine planning and should provide basic information for optimization of blending and crushing techniques and thus lead to the production of uniform coke.

Jan 1, 1970

By L. Tartibu, S. Assuli, P. Nkul, A. Kabimba, W. Elongo, N. Makhotla, D. F. Verwey, F. G. Ndiitwani, J. Bilali, T. Mukongo

The presence of colloidal silica negatively impacts various hydrometallurgy processes. This paper details the nature of colloidal silica, operational issues caused by colloidal silica, as well as various mitigation measures. MMG Kinsevere observed severe phase-continuity instability, increased crud formation, and reagent consumption, and reduced current efficiency in electrowinning with a deterioration in copper quality. Historical mitigation measures were initially implemented but failed to solve the problem. MMG Kinsevere successfully achieved efficient silica removal without adverse effect on the solvent extraction with the use of DEHSCOFIX® SC12 coagulant. A week into the coagulant trial, silica concentration had dropped from > 1500 mg/L to within 500 mg/L. The solventextraction plant recovered its stability and again operated at maximum capacity. Additionally, improvement was observed on current efficiency and copper cathodes quality with use of the coagulant.

Jan 1, 2023

By BHAMIDIPATI S. SASTRY, SRIVATSAN J. SRIDHARAN

Pressure losses in mine ventilation systems are estimated using friction factors and shock loss factors. The efficient planning and designing ofmine ventilation systems depend on the accuracy of the friction factors as well as the shock loss factors that are taken into consideration. While there is a much more acceptable knowledge of what constitutes friction loss in mine roadways, the shock loss factors are in general readily not available for all possible contexts of flow separation phenomena in mines. One such special case of shock loss in mines is the train of mine cars in the airway. Mine cars are widely used for the transportation of material, and the information on shock loss factor for mine cars is limited. This paper examines the pressure loss occurring due to a train of mine cars in an airway using scale model studies and numerical investigations. Computational fluid dynamic (CFD) studies are conducted using four different turbulence models. The performance of different turbulence models is analyzed by comparing it with the experimental results. The study suggests that the boundary layer resolution method is significant in the simulation of shock loss. From the study, it is found that the shock loss factors from presently available model overestimate the pressure loss by 7 to 15 times. A better prediction model for the shock loss factor of a train of mine cars in the airway is proposed using the experimental results.

Jul 24, 2020

The Callie Underground Gold Mine (Callie) is owned by Newmont Asia Pacific and located 531 km north-west of Alice Springs in the Northern Territory. Historically, stopes have been mined utilising a primary and secondary stoping sequence with cemented aggregate fill and rock fill respectively. Current and near-future mining will employ long hole open stoping with rib pillars and rock fill with a paste fill system approved to allow a higher extraction ratio from mid-2011. The Callie rock mass is of good quality with little or no mining difficulties during development and stoping to a depth of 1140 m below surface. Development is currently occurring at depth of 1360 m below surface. Stress damage previously observed only in secondary stope accesses is now observed in development unaffected by stoping stresses. A change in rock mass properties is being experienced with depth, with more pronounced and frequent joint planes. Also, other structures are intersected more commonly, such as lithological boundaries and fault zones. The 'Callie rock factory' mentality that has persisted for years is challenged. This paper covers an appraisal of the stress and ground condition changes at Callie. The appraisal outlines the mine design criterion that was developed and examines the transition from a low stress environment to one where stress damage is observed. Discussion includes a judgement on the rock mass damage observed in development, the dominant geotechnical factors influencing the change in ground conditions, and if a correlation can be made between the observed rock mass damage with stress through the use of numerical modelling.

Nov 25, 2010

By S. A. Shoop

Vibrations from thirty-seven blasts were monitored using three seismographs. Data analysis showed that square root, cube root, and site-specific scaling predicted ground motion with equal reliability. Imprecise prediction is caused by geologic and blast variability, particularly inaccurate delay times. Vibrations at some mines were consistently lower or higher than vibrations reported in the U.S. Bureau of Mines studies. Regulations based on USBM data could then be too conservative or lenient. Predominant vibration frequencies were generally less than 50 Hz, but several blasts had significant energy up to 125 Hz. In some cases energy was concentrated at frequencies corresponding to delay intervals.

Jan 1, 1983

By Roger Lucas, Dale Nies

The McLaughlin Mine is an open-pit disseminated gold mining operation. Homestake Mining Company's approach to solving some of the blasting problems inherent to this type of deposit provide an interesting case history. Geology, although unique and site specific, is overall similar to other mines within the Western United States over-thrust belt and demonstrates an excellent example of the blasting conditions and requirements common to most of these operations.

Jan 1, 1990

By Arthur L. Crawford, R. E. Head, Glen Burgener, F. E. Thackwell

"INTRODUCTION This report embodies the results of a detailed statistical microscopic examination of the ore and the mill products of the Silver King Coalition Mines Co., Park City, Utah.The study was conducted under the joint auspices of the United States Bureau of mines is cooperation with the University of Utah at Salt Lake City, Utah. The work was done in the cooperative Microscopic Service Laboratory, which was equipped by contributions from the following companies: Utah Copper Co., International Smelting & Refining Co., American Smelting & Refining Co., United States Smelting, Refining & Mining Co., Tintic Standard Mining Co., Silver King Coalition Mines Co., and Park Utah Consolidated Mines Co. The salaries and the other costs involved in operation of the laboratory were met by contributions from certain supporting companies. In addition to the regular personnel of the laboratory the Bureau of Mines contributed the part-time services of a microscopist-consultant to direct and assist with the technical work.ACKNOWLEDGEMENTSThe authors acknowledge the courtesies extended by the Silver King Coalition Mines Co., through its general manager, M. J. Dailey, in furnishing the various ores and products on which the study was made, together with general information concerning the problems encountered or recognized in connection with the milling of the Silver King ore."

Jun 1, 1934

By Jonathan Ludlow

This document is the final report of a study aimed at defining the relative contributions of various sources of respirable airborne dust on longwall faces. In order to define the contribution of various primary sources, continuous dust level data were recorded on five longwalls for an average of five shifts at each. By analysis of these data with records of face activity, it was possible to determine the overall contribution of each of the major elements of the longwall system to overall respirable dust exposure at various face locations. Average levels were determined for roof support generated dust, conveyor and intake dust and for dust levels during various shearer activities. When average levels are compared between mines, a significant degree of consistency is noted. The next phase of the study was aimed at differentiating the various dust sources associated with the shearer. To this end 'fly cuts' varying from 6 in. to 30 in. were closely monitored as were dust levels at operators' positions over the various segments of longwall cycle. These data indicated that the clearance ring of the shearer drum as a disproportionately heavy contributor to shearer dust make. A statistical analysis of the effect of shearer haulage speed on dust make revealed that high haulage speeds are associated with low specific dust make.

Jan 1, 1983