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By A Morris

The Express Rail Link (XRL) will provide high-speed rail services from Hong Kong to Guangzhou and a connection to the national high-speed passenger rail network serving major cities throughout Mainland, China. The HK$ 67 B (NZ$ 11.5 Billion) project is of great strategic importance for Hong Kong and is being implemented to a very tight schedule, from early 2010 with completion targeted for 2015.The works include a 15 platform terminus station in West Kowloon, 26 km of twin track tunnels from the terminus to the Hong Kong/Shenzhen boundary at Mai Po, tunnel vent shafts/adits/emergency rescue siding and a stabling siding facility. Trains on the Hong Kong section are intended to operate at speed up to 200 km per hour and up to 350 km per hour on the Mainland section.This presentation will provide an overview of the entire XRL project, with a focus on the challenging geotechnical and spatial constraints on the tunnel works. This is an abstract only. No paper was prepared for this abstract.

Mar 8, 2011

By Henry M. Harris

A study was made by the Bureau of Mines to determine if shapes of oxide-glass compositions could be roll-formed at high temperatures, and to find the conditions required for adequate formability. A unit with directly connect' furnaces and heated rolls that allowed forming of most of the compositions developed. Glasses of the feldspar type were chemically unreactive with the alumina grains, and allowed the best roll forming. Optimum forming was attained at temperatures of 1,400° to 1,530° C, with compositions containing 30 or 40 percent feldspar and 60 or 70 percent alumina. Formability was better when compositions contained minus 325-mesh materials, rather than coarser or finer powders. In many cases, roll-formed shapes had physical properties equal to or better than the normally sintered shapes of the same composition.

Jan 1, 1967

By J. N. Van der Merwe

"The probability of survival of coal pillars is a more rational indicator of stability than the safety factor. Over time, pillars undergo reduction in size by progressive scaling of the sidewalls. The probability of survival is therefore not constant but reduces over time. The rate of scaling can be quantified, and the reduction of the probability of survival as a function of time can therefore also be quantified. The paper describes the link between the factor of safety, probability of survival, and reduction of the probability of survival. Using the safety factor, probability of survival, and the time at which the probability of survival will reduce to 50% is proposed as a more rational method of evaluating pillar stability than the safety factor alone.IntroductionCoal pillar strength has long been the subject of research in South Africa and several other coal-producing countries. However, it began receiving serious attention only after the Coalbrook disaster in 1960. The most important outcomes of the initial investigations were the groundbreaking research by Salamon and Munro (1967) that resulted in the well-known power formula for pillar strength, and the work by Bieniawski (1969) that resulted in a linear formula for strength. The former approach was based on empirical back-analysis of failed and stable pillar cases, and the latter on in situ strength tests on large specimens.The Salamon and Munro (1967) formula has been widely used in South Africa and even adapted for application to hard rock pillars by researchers such as Hedley and Grant (1972).At the time of the initial work by Salamon and Munro, there were only 27 failed pillar cases suitable for analysis. It was not possible at the time to determine site- or seam-specific strength, and the result was a general formula for use in all seams in all mining districts. Since that time pillars have continued to fail and the database continued to grow – as of 2013, there were 85 cases in the database. Using the additional data, there have been a number of re-evaluations of the strength formula and it has also become possible to differentiate between the different mining seams and areas."

Jan 1, 2016

By R. S. Dean

The work of the metallurgical fundamentals section during the past year, representing active experimental investigation or thermodynamic study, may be summarized as the following problem subjects: 1. Low-temperature specific-heat investigations. 2. Development of a method of concentrating gases. 3. Thermodynamic properties of metallic carbides and nitrides, 4. Production of pure chromium from chromium chlorides. 5. Thermodynamic properties of the hydrates of calcium, sulphate. While this list is not identical, with officially designated problems, due to overlapping of subjects and to new developments within specified problems, presentation upon the basis of this subdivision will best serve to review the work of the section.

Jan 1, 1937

De acuerdo a los últimos trabajos realizados sobre la exploración en la mina Cercapuquio, se realizó un muestreo de la veta 53 donde se observó que en la caliza, más allá del ala norte, como en el lugar llamado Chaupirange, existe grandes depósitos de carbonado estático con siderita y limonita, en bolsa de erosión de la caliza normal. Asimismo, se describe otros métodos utilizados para la exploración geofísicadel subsuelo como los electromagnéticos e inducción. En ese sentido, se trata de crear un campo (primario) a través de una corriente eléctrica alterna (primaría) en un circuito. A este campo, es concadenada una corriente (secundaria) que circula en el cuerpo conductor mismo ( en general desfasada respecto de la primaria), que genera a su vez, un campo secundario. Este último se compone con el campo primario para formar un campo total, que está relacionado con la posición y naturaleza del cuerpo conductor que funciona de circuito secundario.

Jan 1, 1956

By P Craig, A Crosky, P C. Hagan, E Elias, B Hebblewhite, S Saydam, D Vandermaat

"Premature failure of rock bolts has been recorded at twelve underground coalmines over the past 15 years in Australia. Over the last four years, UNSW Australia has been conducting an Australian Research Council (ARC) and Industry funded linkage research project into premature failure of rock bolts. The extent of the problem was investigated by underground surveys of mines with known prematurely failed bolts using visual mapping, non-destructive load and ultrasound testing. A major component of this project was to define the environmental factors responsible for corrosion of rock bolts. The environment to which a rock bolt is exposed will include groundwater chemistry, the mineralogy of the strata, atmosphere within the drill hole and even microbial activity. This paper focuses on the groundwater survey and analysis findings to date along with in-hole bolt corrosion coupons installed into field sites. Corrosivity classification systems exist for general corrosion but do not apply to the rock bolt stress corrosion cracking (SCC) problem found in Australian underground coal. The method of in situ investigations is leading towards the building of a corrosivity classification model to assist mines in prediction of premature rock bolt failure. An ‘in-hole bolt corrosion coupon’ development by the project may have multiple benefits of: helping quantify any corrosivity classification system providing an in situ ground support corrosion monitoring tool for testing possible corrosion protection solutions.CITATION:Craig, P, Saydam, S, Hagan, P C, Hebblewhite, B, Vandermaat, D, Crosky, A and Elias, E, 2014. An investigation of the corrosive impact of groundwater on rock bolts in underground coalmines, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference, pp 277–286 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 5, 2014

By Christopher Mark

Colombia is 11th largest coal producing nation in the world, and the world?s fifth largest coal exporter. But while most of Colombia?s coal is mined at large modern surface mines located near the Caribbean coast, there are also underground mines that produce high-grade metallurgical coal. These mines employ traditional hand-loading techniques in a variety of geologic environments, and they have some of the highest accident rates of any Colombian industry. The National Institute for Occupational Safety and Health (NIOSH) has been collaborating with POSITIVA, the primary provider of worker?s compensation insurance to the Colombian underground coal industry, to reduce the economic and social cost of rock falls in these mines. The specific goals of the collaboration are to 1) document practices and conditions in Colombian underground coal mines, 2) identify relevant international best practices, and 3) provide recommendations for developing a national campaign to reduce fatalities and injuries associated with roof falls. NIOSH conducted a survey of seven underground coal mines in four separate coalfields. Five of the mines were characterized by steep dips and weak roof and floor rock. The coal was loaded by hand at all seven mines, though two employed partially mechanized longwall techniques. Wood posts were by far the most common ground support. Roof bolts were not observed in use at any of the mines, and they are unlikely to replace timbers any time soon. While long-term entries generally appeared to be adequately supported, the survey found that less attention was paid to the temporary support that is installed right after the coal is removed. This temporary support is critical for protecting the workers from rock falls, however, because with hand-loading mining methods most of the activity takes place between the permanent supports and face. The study concluded that improving the temporary support in the working faces would be the most effective way to reduce the number of rock fall injuries. The key principle should be that every worker is protected by planned roof support at all times. Ground Support Management Plans, consisting of specific rules about when, where, and what roof support is to be installed, should be the focus of the campaign. Each Plan should be tailored to a specific mine based on the geologic conditions and mining methods in use. The Plan provides miners with clear, simple rules that can be easily understood, while management can easily check to see if it is being followed. Ground Support Management Plans will also provide the campaign with a concrete focus for the necessary cultural change.

Jan 1, 2014

The first session of the Rocky Mountain Coal Mining Institute was called to order by John T. Maulsby, Superintendent of Maintenance and Planning, Columbia-Geneva Steel Division, U. S. Steel Corporation, Dragerton, Utah, representing the past-president. W. K. Dennison, Jr., Superintendent. Koehler line. Kaiser Steel Corporation. Raton, New Mexico, who was unable to attend. Mr. Maulsby welcomed the members and guests, and introduced the President, A. Z. Dimitroff, Mining Electrical Engineer, Health and Safety, District 1-L, U. S. Bureau of Mines. Denver. Colorado. The text of President Dimitroff's address of welcome is as follows: The President's Remarks Guests and Members of the Rocky Mountain Coal Mining Institute: The distinct honor and privilege of officially welcoming you to this, the fifty-seventh regular meeting of the Institute, is indeed a pleasure. Your officers and committees have tried to provide a varied program which I am sure should have something of interest to all of us. The theme of this meeting, "Where Do We Go From here'?", appeared rather fitting for the In¬stitute this year because, as most of you know, until only two weeks ago we thought that this is the last time we will be able to meet at the Colorado Hotel, which has been the favorite spot of most members. Your officers and many of you were literally asking just that question.

Jan 1, 1961

By James A. Robertson

"The Pronto Mine located at the east end of Lake Lauzon, Long Township, some 12 miles east of Blind River is of historic note being the discovery locality and the first producing mine of the Elliot Lake uranium camp. Radioactive bedrock was discovered in 1949, a commercial deposit was verified in 1953 and production commenced in 1955. Production continued to April 1960: total tons milled 2,264,404 from which 4,643,835 pounds U,O, were recovered at a recovered grade of 2.05 pounds U3O8 per short ton.The orebody is in a bed of pyritic quartz pebble conglomerate at the base of the Matinenda Formation of the Elliot Lake Group of the Huronian Supergroup. The rocks strike east and dip 15 degrees to 20 degrees south and unconformably overlie Early Precambrian granite, the upper surface of which is marked by a regolith. Several diabase dykes cut the orebody which is also affected by albite, chlorite, and carbonate-rich alterations. To the south the orebody is cut by a fault. The orebody is 6to 10 feet but locally 10 to 15 feet thick, has a strike length of 3,500 feet and extends down dip for 3,600 feet to a depth of 1,000feet. Some 300,000 tons of ore grade mineralization remain in the deeper portion of the mine.IntroductionThe Pronto Mine, (Photo I) at the east end of Lake Lauzon in Long Township some 12 miles east of Blind River, is of particular interest as being the discovery site and the first producing mine of the Elliot Lake camp.Production at the Pronto Mine commenced in 1955 and continued until 1960 when the mill was converted to treat copper ore from the nearby Pater Mine at Spragge. A description of both mines, based on material provided by the mine staff, was given in the report on ""Geology of the Spragge Area"" (Robertson, 1970).As little study has been done on Pronto geology or petrology since mine closure, the earlier description of exploration and geology is essentially repeated, but shortened, here- the main change being that the stratigraphic terminology has been amended as recommended by the Federal-Provincial Committee on Huronian Stratigraphy (Robertson et al., 1969)."

Jan 1, 1986

By F. X. Tartaron

Behavior of hard-burned quicklime was compared with that of soft-burned quicklime in an oxygen converter utilizing oxygen blowing in a rotating cylindrical vessel, set at a 30° to 60° angle to the horizontal and operated at a predetermined speed of rotation. Four pairs of tests were made) each comparing hard lime with soft lime. Three of the pairs differed from one another in the quantity of lime employed) and the fourth differed in blowing time, All four pairs showed an increase in yield when soft lime was used. Three of the pairs revealed that the ratio of the oxygen consumed with soft lime to the oxygen consumed with hard lime was the same as the ratio of metal yield with soft lime to the metal yield with hard lime. The fourth pair contained an error and could not be included. Finally, a close inverse relation was found between the combined iron in the slag and the combined lime in the slag, which can be expressed by the equation pct Fe = 52.67 -0,906 (pct CaO).

Jan 1, 1967

By Samuel S. M. Chan

The objective of this project was to collect information applicable to the design of ground support systems in deep mines to include in-situ rock deformations, deformation-modulus, stresses, and geology and laboratory physical properties. All data collected was to be integrated and evaluated using a finite-elements computer code. In addition, considerable professional "cross pollenization" was anticipated from the association of University and SMRC personnel. Scope of Investigation Before a ground supporting system can be evaluated, the loading conditions existing in the region of investigation, strength, deformation characteristics, as well as other engineering properties of the rock structure immediately surrounding the openings, together with the pertinent geological information, must be obtained and analyzed. It was for this reason the following items were included in this research project: (1) The selection of a suitable area for the investigation. (2) The mapping of the important geological features of the area of investigation. (3) The measurement of in-situ deformation of rock masses immediately surrounding an underground opening of the area of investigation. (4) The determination of ground stresses. (5) The obtaining of in-situ modulus of deformation of the rock masses. (6) The testing of useful engineering properties of

Jan 1, 1972

By H. B. Brunot

On April 26, 1949, the Bureau first approved a machine designed to replace the cycle of cutting, blasting, and loading coal by a single operation. This machine took the coal directly from the solid face and delivered it to transportation equipment. By January 1, 1955, 30 approvals for designs of machines of this type had been granted by the Bureau. In the main, this paper describes briefly the action of the various designs approved as permissible. In addition, the approval number, the date of approval, the voltage of the power supply, the number and character of the explosion-proof accessory parts, the size of the trailing cable, and the overcurrent protection at the outby end of the trailing cable are given for each design. Since no similar information has been published by the Bureau, it is hoped the material in this paper will be valuable in giving the mining public an organized look at the various machines of this nature that have been approved as permissible by the Bureau.

Jan 1, 1956

By Mark S. Sanders

This report discusses the development and testing of prototype gloves for underground mining work. An analysis of HSAC hand-finger injuries revealed three high-risk jobs: laborer, mechanic, and roof bolter. Laboratory tests of dexterity and protection were performed using six off-the-shelf gloves. Two prototype gloves were developed. Both were Kevlar-cotton blend knit gloves. One had polyvinyl "Ks" screened on the palm and fingers, and a hand pad sewn into the palm. The other prototype had the palm and fingers coated with a sol id layer of polyvinyl and had no hand pad. Field tests revealed that the solid-coated gloves were preferred by workers, but that the polyvinyl melted when working with hot drill steels.

Jan 1, 1985

By Y. Okahara

The chlorination behaviors of pure iron and manganese oxides were investigated by combining a thermogravimetric analysis (TGA) technique with batch-boat roasting followed by leaching. Ferrous and manganeus oxides could be chlorinated readily, but, in the absence of a reductant, the higher oxides of both iron and manganese were difficult to chlorinate. Thermogravimetric analysis curves were drawn to illustrate the complexitites of the reactions, and the possible mechanisms were discussed. Then three manganiferous materials from the Cuyuna Range of Minnesota were treated by a process involving the selective chlorination of manganese followed by leaching. The results were interpreted in the light of the chlorination mechanisms observed on the pure iron and manganese oxides.

Jan 1, 1969

By John C. Ferm

This report summarizes the results of an investigation of geologic factors that contribute to roof quality in underground mines in the Pocahontas #3 coal bed in southern West Virginia and southwestern Virginia. The investigation consisted of three phases, the first of which was selecting for detailed study five mines which represented the range of roof conditions, mining practices and geologic phenomena. This was accomplished by a statistical analysis of questionnaire data from 35 mines. The second phase consisted of detailed mapping in a "good" and a "bad" top area in each of the five selected mines and resulted in a qualitative assessment of geologic factors contributing to roof £alls. In the third phase, five mines were selected in which most non-geologic factors believed to contribute to roof falls were relatively constant but displayed a wide variety of geologic characteristics. Data from these mines were analyzed to test the qualitative assessments from Phase II. The primary result of this investigation is that slickensides arising from different geologic causes are the major geologic features leading to roof falls. These slicken-sides are found in ancient slump deposits, fire clays and sandy fire clays and channel contacts. Falls also occur where thick sandstone bodies directly over-lying the coal contain abundant shale or ironstone pebbles and coaly strips. The best top material is a sequence which consists of shale grading upward to sandy shale and sandstone within 30 feet of the top of the coal. Thick sand-stone units (301) without pebbles also provide good top.

Jan 1, 1978

By M. Saghaeian, R. Hejazi, L. Hosseini, M. V. Sheikhzadeh

Blaine number has long been used to evaluate the pelletising ability of iron concentrate in the industry. Much information and practical data are available about the effect of Blaine number on pelletising efficiency of different concentrate types. But not many researchers have focused on the effect of Blaine increasing method on pelletising behaviour of coarse concentrates. In this paper the effect of two different grinding methods (i.e. HPGR and Ball Mill) on physicochemical properties of coarse magnetic concentrate green and fired pellets were investigated. Microstructural studies by Field Emission Scanning Electron Microscope (FESEM) showed that the concentrate for which the Blaine number had been increased through HPGR grinding, has flake-like morphology. In contrast, increasing the Blaine number through ball mill grinding results in more granular particles. Two samples were prepared using HPGR and ball mill. The Blaine number of the HPGR product and ball mill product were 900 cm2.gr-1 and 1200 cm2.gr-1 respectively. The results revealed that pellet properties of this HPGR product are comparable to that of the ball mill product; this is due to the fact that the flake-like morphology leads to enhanced pelletising performance of coarse magnetite concentrates. Keywords: Iron pelletising, Blaine number, HPGR, ball mill, coarse particles

Jan 1, 2020

By R. S. Dean

This report, the third of a series of annual reports of the Metallurgical Division to be released in this form, covers the fiscal year July 1, 1936, to June 30, 1937. The technological work of the division is performed by sections. Thus, an efficient organization is provided to prosecute the various problems under investigation, and a logical system is set up for presenting the material contained in this report.

Jan 1, 1937

By L. C. de Kooker, K. Esmaeili, I. Musonda, M. Ferentinou

A numerical investigation of the effect of pore pressure regime on the safety factor and the critical failure mechanism is presented for fly ash storage facility. Pore pressures’ measurements from standpipe piezometers and pore pressure estimated from seepage analysis are used to compare the factor of safety for a fly ash slope. This was applied for considering static and seismic scenarios. A probabilistic approach was applied to account for the uncertainties resulting from the limited data available and support a qualitative risk assessment evaluation. Slope stability analysis is conducted in two and three dimensions, adopting the limit equilibrium analysis approach, and also a finite element seepage analysis, to assess the stability of the slope. The two-dimensional cross-sections were extruded to three-dimensional models to estimate the factor of safety and associated shear failure. The results from the performed analysis suggest an increase in safety factor values of 5%.

Mar 27, 2024

By S. W. Zoldok

"ERRATUMFor paragraph 1, page 1, read the following:The Cle Elum nickeliferous iron deposits occur on an unconformable contact between the serpentine and overlying Swauk sandstone formation and extend about 2 miles along the Cle Elum River in Kittitas County, Wash.The linear extent of the deposits and their proximity to a large source of,electric power and coal supply indicated that a development program was in order to determine the probable grade, extent of the ore bodies, and a suitable metallurgical process for recovering the iron, nickel, and chromium from the ore.The northern portion of the serpentine formation was investigated by the Bureau of Mines from August to December 1943 and from August to October 1944. The investigation consisted of road building, diamond drilling, sampling, and metallurgical tests.The Geological Survey assisted with logging of cores and made geologic and topographic maps."

Feb 1, 1948

By L. C. IlsLey

Cooperation between the United States Bureau of Mines and the Safety in Mines Research Board of Great Britain, continuous, since 1924, s made possible this and other papers on safety subjects. Grateful acknowledgment is made to representatives of the board for their assistance in arranging visits to several mine-safety stations, and to F. R. Wynne, Deputy Chief Inspector of Mines, for arranging visits to mines in Great Britain and certain other countries in Europe. During the summer of 1927 the writer had the privilege of visiting the mine-safety testing stations An Great Britain, Belgium, Germany, and France, in the order named. All of these countries have large coal mines, many of which are rated as gassy. Therefore, a the installation of electrical equipment is contemplated each of these countries is confronted with the same safety problem as is the United States that is, the development of electrical equipment that will not, ignite gassy atmospheres should they through neglect or accident surround the equipment. The means employed by these countries in safeguarding gassy mines should therefore be of general interest to safety engineers of American coal mines, and a brief survey is given for each of the four countries mentioned. The fourth or last of these surveys covers conditions in France.

Jan 1, 1929