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The Mine Safety and Inspection Act, 1994 of Western Australia recognises the importance of ground control in underground mining. The recent safety performance of underground mining is summarised in terms of the most common causes of injury and fatal accidents. A review of current ground control practices is presented and the concepts of local and large-scale ground control are introduced. The need for a more systematic approach to ground control is considered to be directly related to requirement to improve safety performance. The new regulations will require that certain geotechnical issues be addressed during the life of a mine. To comply with the regulations it is suggested that a ground control management plan be developed for each mine. The geotechnical issues associated with the ground control management plan are reviewed and hazard recognition aspects discussed.

Jan 1, 1995

By Ryosuke O. Suzuki

A combined process of electrolysis of CaO in the molten CaCl2 and of calciothermic reduction, so-called OS process, was applied to prepare metallic vanadium directly from V2O3. The fine metallic powder containing 1860 mass ppm oxygen was obtained using 0.5mol%CaO-CaCl2 melt for 10.8 ks at 1173 K. The oxygen level did not decrease further even when twice electricity was applied. Because the metallic vanadium could be electrochemically deoxidized to the level of 10 ppm oxygen from 1.48 %, the large amount of by-product, CaO, due to reduction and the large surface area of the fine particles are the reasons of high oxygen content in the reduced powder.

Jan 1, 2006

By Dhawan AK

On 8 July 1993, a landslide of about one million cubic metres of rock blocked the river Satluj near Sanjay Vidyut Pariyojana - Bhaba project and caused flooding into the Bhaba Power House (120 MW) resulting in suspension of power generation. The concerned authorities desired an early removal of the blockade by an underwater blasting operation into the over topping water to reduce the water level at the blockade and resume power generation in the power house. In the absence of underwater drilling, it was essential for the blasting technique to be used where no cavity to confine the explosive was required. For this reason mud capping and plaster shooting with directional throw were used and additional specially fabricated mild steel pipe charges were used under high current for an underwater trenching operation. By employing these techniques the river blockade was removed up to the required depth and on 8 September 1993 the Power House resumed the power generation.

Jan 1, 1995

By George Sachs

THE process of recrystallization has not as yet been explained satis-factorily. Some definite conclusions could be drawn from recent investi-gations, such as, for example, that recrystallization is a process of nucleus formation and crystal growth 1and that the orientations of the nuclei correspond to some fragments of the original crystals, which have been considerably distorted during deformation.2 There are, however, a number of metals and alloys crystallizing in the face-centered cubic system, which form a particularly simple orientation if recrystallized as a sheet.3 Such a sheet is almost a single crystal with the cubic axes parallel to the rolling, transverse, and normal directions of the sheet. This preferred cubic or (100) orientation of the recrystallized sheet has been considered to be very different from the rolling structure of the same metals,4 but there are two reasons why this last supposition remains open to controversial discussion. The first reason is academic: In practically all cases except the one mentioned above, close correlations and similarities between rolling and annealing orientations have been observed; for instance, in iron and steel sheet.6 Secondly, no deformed metal actually forms a-simple orientation. In any thoroughly investigated case a number of different orientations and considerable scattering or deviations from the ideal orientations have been found., It is generally true that investigations on single crystals have shown that a definite orientation is approached in stretching or in compression of an originally undisturbed crystal.7 In the special cases, however, where the initial orientation was close to an important crystallographic direction that differed from the final "ideal" orientation, the resulting orientation changed very little by deformation, staying somewhere in the vicinity of the initial orientation." Such deviations

Jan 1, 1940

To suppress the natural bacterial action in acid mine drainage (AMD), the major contributor to acid formation. Approach Recycle partially-treated affluent back to the source of AMD within a mine, or to the coal or coal-waste stockpile. This effectively eliminates any further biologically-promoted AMD by inhibiting catalyzed weathering or oxidation by acid-forming bacteria. How it Works AMO-type effluents can be largely reduced by "recycling" the acidic outflow back to the source of AMD within a mine or to the Input side of a waste pile to percolate through the reactive pyrite and bacteria mixture. The bacteria in the cell thrive on the oxidation of ferrous to ferric iron through the electron transfer, Fe2 +[=]Fe3 + + e. Its reaction product [s, therefore, essentially ferric iron. While small quantities of Fe3 + will not interfere with the exponential multiplication of the bacteria

Jan 1, 1982

By L. C. Morganroth

Magnesites are of two general classes - massive and crystalline.

Jan 1, 1915

By Albert Ledoux

SEVERAL years ago my firm was representing the Mt. Lyell Co. of Australia, which was shipping its blister copper to a refining works in the United States. After the contract had been running for many months, the superintendent of these works discovered that if water was poured upon the surface of the bars much of it would disappear into the interior through blow holes. -Some experiments made by him showed that this could be a considerable amount, so that copper which had been rained on before it was weighed, although the surface appeared dry, nevertheless would contain water. It had frequently occurred in our experience-as samp-lers that the drillings from a lot taken by boring would come out quite wet, and in some cases, indeed, water would drip into the sample pan placed below the bars, due to the fact that the drill had penetrated a cavity or cavities containing water, which presumably got into the cavities at the time the copper was water-cooled after casting, there being, perhaps, no outlet to the surface. So far as I know, until this discovery at the refining works, no. one had thought that rain could penetrate into the interior of blister copper; at least in any quantity sufficient to be considered.

Jan 10, 1922

The Porgera gold deposit in the Papua New Guinea highlands contains about 387 tonnes of gold. The results of its exploration show the benefits of persistence and commitment to this difficult deposit. The mineralization consists of a complex intermix of auriferous and argentiferous sulphides, gold tellurides and free gold as disseminations, veins, stockworks and breccia matrix. Its deposition was structurally contolled within a system of mafic diorite intrusions and adjacent sediments. Two styles of alteration accompany the mineralization. Gold grades vary erratically throughout the deposit. Over a period of 22 years nine phases of exploration have been undertaken by six companies or consortia of companies. Surface rock chip sampling, geological mapping followed by scout and systematic grid diamond drilling have been the most successful exploration tools. Exhaustive metallurgical process investigations and economic evaluations of mining options have been invaluable in guiding the exploration towards defining the ore body. Impetus was given to the project during times of flagging enthusiasm by several important discoveries and a breakthrough in the metallurgical processing approach. The discovery of high grade ore deep in Zone VII in 1984 turned this marginal deposit into a potentially very large gold mine.

Jan 1, 1987

By Waladan M, Elliot B, Rankin W. J

A survey was undertaken on the Kalgoorlie Nickel Smelter in which samples of slag and matte were taken along the length of the integrated flash smelting furnace and analysed to determine the variation of nickel and iron concentration. At the same time the oxygen potential of the slag and matte was measured using disposable tip solid-state oxygen probes. The results show that the oxygen potential of the slag is higher than that of the matte and that both decrease from the reaction shaft end to the slag tap hole end of the furnace. The slag and matte are not at equilibrium except towards the tap hole end. Reduction of nickel and magnetite from the slag occurs before the slag enters the slag-cleaning appendage by reaction with iron in the matte. Thermodynamic modelling and laboratory experiments showed that the equilibrium nickel and magnetite contents of the slag in the absence of a carbonaceous reducing agent are about 0.4 per cent and 7.5 per cent, respectively. A carbonaceous reductant is required to obtain a lower nickel content in the slag.

Jan 1, 1991

By John Hall

THE Fremont test for measuring the energy consumed in breaking a notched bar of steel is not so well known in this country as it deserves to be. The test specimen used in this test is about 3/8 by 1/4 by about 1 1/4 in., notched with a hack saw on the lower side to cause the piece to break at a fixed point. A weight of 10 kg. falling 4 m., and provided with a knife or chisel which strikes the specimen, breaks the test piece by impact. The residual force in the falling weight after it has broken the specimen is recorded by a suitable device, and the difference between the total energy and the residual energy of the weight (in kilogrammeters) is the force consumed in breaking the specimen. An experience of several years with the Fremont testing machine has shown its great value in readily detecting brittleness not revealed by tensile testing or slow bending testing. I this paper it is proposed to discuss (1) the supersensitiveness of the test as applied to cast steel and (2) its value in revealing the effect of heat treatment under certain conditions. .

Jan 7, 1913

By H. Reinhardt, P. Haglund, J. Rydberg, B. Lunden

As legislation to minimize pollution in effluent streams becomes stricter, it is important to treat used acid pickling baths before discharge. This is usually achieved by neutralization of the acids and precipitation of the dissolved metals in such a way that neither acids nor metals can be re-used. A process has been designed and tested on a pilot plant scale to recover both acids and metals from a stainless steel pickling bath leaving only Na2SOs in the effluent. In this process, H2SOr is added to the spent pickling liquor and the recovery of the pickling acids HN03 and HF is achieved by solvent extraction, using TBP in kerosene as the organic solvent. The extracted acids are stripped with water, giving an acid concentration high enough for direct use in the pickling bath. Molybdenum is also extracted by TBP and is recovered in a separate step. The other metals, Fe, Cr and Ni, are precipitated from the raffinate as hydroxides, dried and recycled to the metal process. In evaluating this process, comparative experiments with mixer-settler and pulsed column have been performed. The process described is being considered for use by a Swedish company pickling 70,000 tons per annum of stainless steel.

Jan 1, 1973

Report of President The important fact of the year 1916 is that on July 25 contracts were executed by which the American Society of Civil Engineers because an additional Founder Society and arranged to make its permanent home in our building. The contracts provide for the construction of three additional stories to the building, the American Society to pay the cost tip to $250,000, this being considered equivalent to what each other Founder Society had contributed, the American Society to participate in the original Carnegie gift and have an equal share in the property with each other Founder society. The construction of the addition to the building is under way, $62,525.04 having been expended thereon in 1916. It has been found that, clue to war conditions and the advanced price of materials, the cost of the addition will be $300,000. The founder societies have been requested to assume the extra $50,000, one quarter each. This work is in charge of a Building Committee consisting of H. H. Barnes, Jr., Chairman, E. G. Spilsbury, Charles Warren Hunt and Charles F. Rand. At the request of the Founder Societies, important alterations were made in the lecture halls on the fifth floor of the building to make the same suitable for social functions of the societies. The cost, $6,642.08, was advanced by the United Engineering Society but is to be paid eventually by the Founders. The Library of the civil Engineers is being merged with the Library of the United Engineering. Society and the other founder societies. At the present time the membership of the four founder societies is 29,000 and of associate societies 23,000, so that a total of 52,000 engineers now have their headquarters in our building. The value of the real estate now owned by this Society is $1,647,171.16. This sum will be increased at the end of 1917 by the amount of the cost of the addition to the building.

Jan 3, 1917

By Frederick Burbridge

The Morning silver-lead-zinc mine of the Federal Mining & Smelting Co. is about 'two miles northwest of Mullan, Ida. The lode is a metasomatic fissure vein. The orebody is approximately 2000 ft. long within the bounds of the property and varies in width from knife edge stringers to 50 ft. It has been developed to a depth of 3600 ft. and stands nearly vertical in Revett quartzite, which .strikes north 65" west. The high-grade veins and lenses are generally mixed with waste (siderite, quartz, and quartzite). The average grade of ore to sorting plant in 1921 was 4 oz. silver per ton, 8.6 per cent. lead, and 4.1 per cent. zinc. Wall rock stands only a short time without timbering. The minimum angle of gravity flow is 45". The ratio of waste sorted out to ore is 6 per cent. No gases are generated underground and temperature has no influence on mining operations. Fresh air is forced down the air raise and up the main shaft. Drifting and Stoping Main drifts 12 ft. wide and 13 ft. high are driven every 200 ft. (vertically) and are connected by raises 125 ft. apart. These raises consist of three compartments (chute, tramway, and timber slide) and are for the purpose of ventilation, access, and hoisting supplies to stopes. Ground is stoped between raises. Chutes are placed every 25 ft. for drawing off ore broken in stopes. Waste for filling is obtained from waste raises off the stope in walls or waste is dumped from the level above down the chute compartment of raises, which is bulkheaded so that waste can be drawn off at any floor as required. Timbering Posts and caps for square sets (varying in diameter from 6 to 24 in.) are cut to length in a sawmill on the surface. No preseratives are used. Timber is taken on a flat car along drifts to a raise nearest the working place and hoisted as required. Practically no timber is salvaged for

Jan 1, 1925

Weekly Capacity ? Current Schedule Rate (198.5 tonnes / hour) X Skip Time (112.7 hours) X Effectiveness (85%) = Weekly Capacity (19,015 tonnes) Capacity Conclusions - Existing hoists optimized are best option for Fraser Morgan (>20M + schedule for other). - Peak will have to be managed. - Critical to have equipment & infrastructure in best possible condition to ensure reliability.

Feb 1, 2008

The estimation of local recoveries, such as the local recovered tonnage of ore and its corresponding grade at a given cutoff grade, is an important problem in a selective mining operation. Multigaussian kriging provides a simple solution to this specific problem. The solution is also complete in the sense that local recoveries are estimated together with their estimation variances. It is thus possible to assess confidence limit intervals on the estimated recoveries. Multigaussian kriging has been applied to the Jerritt Canyon deposit in a most realistic situation. The various steps of the estimation procedure are presented in detail and the potential of the method is demonstrated in view of the results. The obtained results show that the estimated recoveries are in good agreement with the actual recoveries and the actual estimation errors are correctly predicted by the estimation variances. Multigaussian kriging thus appears as a useful and fully operationable tool for the mining industry.

Jan 1, 1986

By Tagawa H

In Japan, geological condition do not only vary in a wide range of strata but are also extremely complex with the existence of faults and aquifers. With respect to rocks, in particular, it is very rare that homogeneous rocks are distributed uniformly. In general, geological conditions are distributed in a wide variety, ranging from earth, sand, soft and medium rocks to hard rocks. Under these geological conditions, when planning of the tunnel construction is to be made out, either blasting method or tunnel boring machines must be selected taking into consideration the geological structures along with the designed tunnel route,' possibility of encountering aquifers, hardness of rocks anticipated and also, the adjacent environ- mental conditions. In the process of select- ing an excavation method,, it is important to make a comparative investigation between the above two methods considering the advantages and disadvantages with regard to the respective operating efficiency, economical efficiency and the conditions and scope of application as well. Furthermore, in addition to these considerations, the recent environmental restriction, which does not allow the blasting in the surroundings of residential areas, must also be taken into account. Because of this, in some cases there is no alternative but to use a static excavation method or a tunneling machine even when these are less efficient than blasting.

Jan 1, 1987

By B. Silliman

THESE ores occur in the Laurentian rocks in the town of Clifton, St. Lawrence County, New York. The Clifton Mining Company have opened these magnetites upon their estate of 23,000 acres, on the waters of the Grasse River, an affluent of the St. Lawrence, which flows for about nine milt",3 across the estate, exposing a section of the formation, and affording ample water-power at numerous points. In approaching this district from De Kalb Junction, upon the Watertown and Ogdensburg Railway, the observer passes from the zone of the specular ores, which abound to a great extent in Jefferson County, across a belt of non-metal-liferous limestones, continuing for some miles intermingled with metamorphic rocks, and gradually giving place to heavy beds of granitic and porphyritic gneiss, the weathered surfaces of which present a gray and rough appearance, from the washing out of the feldspar; leaving the quartz very prominent, and completely disguising the real character of the rock, which, when freshly broken, has a lively reddish appearance from the predominance of flesh-colored and red feldspar. Beds of fine-grained quartzite appear also intercalated in the granitic gneiss. These are the dominating rocks of the magnetite region, but the magnetite is always found, so far as the speaker's observation extended, associated with beds of calcite, carrying hornblende, black and green, biotite, and brown garnet interspersed with yellow and magnetic pyrites. The strike of these rocks is about northeast, and their dip about 40' to 45' southeast

By Carlos Ortiz, Pedro Quispealaya

"En este trabajo se detalla las experiencias de innovación de operaciones en una mina subterránea, logrando una visión profesional remota hacia los operadores de: Locomotoras durante la trayectoria de retroceso, Inspección de piques, el arranque y parada de equipos etc. En todos estos empleamos dispositivos electrónicos versátiles en tamaño, peso, capacidad de almacenamiento en memoria y otras relacionadas a la comunicación digital. En esta oportunidad en especial nos referimos a cámaras de video y transmisores aplicando tecnología inalámbrica."

Sep 1, 2017

Hoisting ropes are constructed of wires and strands positioned helically around the axis. This helical positioning causes that, in the rope loaded at the end with the weight Q, the longitudinal displacement u, axial force P, torsional displacement v and constant torsional moment M are generated. More over, the proper weight of the rope q gives the force acting along the axis of the rope. This force changes its value from 0 at the bottom to qL at the top. This force gives, along its length, a variable torsional moment making the rope rotate. During the movement of the conveyance downwards the falling part of the rope rotates, which makes it untwist on the section up to the half-depth of the shaft and twist on the other half-depth. As the result, the twisting lay of the rope changes increasing in the upward direction and decreasing downwards. The angle of twist of the strands changes in an apposite way. When moving upwards, the uplifted rope does not twist and retains its state of deformation up to the moment when it passes over the pulley. Next, the cycle of untwisting and twisting repeats during the movement of the other conveyance downwards. This phenomenon is known from mining practice. It was also analysed, in the works of Glushko (1966) and Popowicz (1963).

Jan 1, 1995

By Paul Billingsley

The term Boulder batholith was first applied in 1897 by W. H. Weed2 to the extensive mass of granite in western Montana within whose borders occur the ore deposits of Butte. In a general way this was known to extend from Helena on the north to the Highland Mountains near Butte on the south, and to be relatively narrow in its east-west diameter. Its intrusive relations to the surrounding sedimentary rocks, and its probable Tertiary age, were described by Weed, but in many ways his statements, based upon incomplete data, have required revision. Most notable of the errors of this description of the batholith were the failure,3 since corrected, to recognize the intrusive contact of the granite with the capping of andesite, and the complete absence of any reference to the many extensions of the granite beyond the somewhat narrow limits of its largest exposure.

Jan 1, 1915