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The large increase in secondary industries in this country, during the war and post war periods, has caused a shortage of capacity for the production of merchant bar.To overcome this shortage, an expansion of rolling mill facilities has been undertaken by the Broken Hill Pty. Co. Ltd. A small, but modern, merchant mill has been erected at Kwinana in Western Australia and a strip and skelp mill is under construction at Newcastle. The latter mill will roll strip and skelp at present being rolled by the Newcastle 10 in. Merchant Mill, enahling this mill to concentrate on merchant bar production.The Kwinana mill was installed to supply the Western Australian market. This state has a small population (approximately 658,000) and is not at present highly industrialised. It was necessary, therefore, to design a mill which would be capable of producing a wide diversity of sections and could be expanded as the demand increased. To begin with capital expenditure had to be kept within reasonable bounds. The design work for this mill, with the exception of a few specialised items of equipment, was carried out at Newcastle.All design work for the Newcastle mill was carried out by the lVIorgan Construction Co. of America. Although initially intended for rolling flat. products, the designers were asked to make the mill as flexible as possible, so that should the market for flat products decrease, this mill with additional equipment could undertake the rolling of medium sized sections.

Jan 1, 1957

Filtration of pulps of varying densities is an essential operation in the hydro-metallurgical production of zinc. The use of filters naturally applies only to the "wet" plants, and in these varying types and sizes are in commission. At Risdon, the Moore suction filter is used for the heavier pulps, except in one instance, where a modification of the Butters-Cassell filter is installed.Filter presses are in general use, and of these, one is a washing unit; the plates, and frames are of cast iron or mild steel, except in one case which is a centre feed press having wooden frames.FILTER DESIGNThe problem of filtration presented itself very early in the history of Risdon and the first developments occurred in what was termed the 250 -lb. plant. Here experiments were made with many types of filters, and as this was the pilot plant on which the design of the 10 ton plant (10 tons of zinc per day) was based, quick decisions were necessary.An Oliver type filter was chosen for the heavier pulp or residue, and a Shriver wooden frame filter press for the lighter pulps.To this day, but with a number of variations, filter presses continue to function unopposed in their particular field; however, the Oliver filter was soon superseded because it was found impossible to wash the filter cake efficiently without repulping; consequently its use was abandoned and the Moore filter adopted.Both- these filters have been modified and developed in many ways to meet the requirements of a zinc plant, but they retain their original basic features.

Jan 1, 1949

By Margaret R. Egan

The Bureau of Mines subjected three commercially available brands of transformer fluid to a series of combustion studies. The experiments were conducted in the intermediate-scale fire tunnel, which was designed to simulate environmental conditions in underground mines. The work was divided into three phases. In phase one, the brands were compared for gas production, smoke characteristics, and combustion yields. In phase two, the production constants of transformer fluids and other fuels were compared for the rate of formation of gas and smoke as a function of fire size. In phase three, several diameters of liquid-pool fires were compared in terms of fire size and burning rate. These transformer fluid measurements will be added to the existing coal and wood data that can be used as a basis of comparison for future studies of other mine combustibles. Further research into the combustion product emissions from combustible materials found in underground mines will lead to improved and realistic fire detection and suppression systems,

Jan 1, 1986

By Joseph A. Sutton

This study was undertaken by the Bureau of Mines to determine whether the sulfur-oxidizing bacterium Thiobacillus thiooxidans could use sulfur compounds to produce sulfuric acid in sufficient quantities to leach valuable metals from low-grade ores. The results of extended tests indicated that the bacterium is capable of extracting appreciable amounts of copper and cobalt from ore and mineral samples when sulfur is available in a state that can be readily assimilated by the organisms. Under the conditions of these tests, this organism was not able to assimilate and oxidize the sulfur as it occurred in the ores and minerals. Ores containing copper minerals in the silicate, carbonate, and oxide forms, in the presence of elemental sulfur, were more susceptible to bacterial action than ores containing copper minerals in the sulfide form. Thiobacillus thiooxidans remained active on elemental sulfur in the presence of some of the ores which were tested, but could not tolerate others. Therefore, strains of the bacterium were progressively adjusted to increasing concentrations (0.5 to 10 grams) of the individual ores until they could remain active on 10-gram portions of all ores being tested.

Jan 1, 1961

By Charles Zdazinsky

Over-break is undesirable in underground civil construction because it excessively damages rock along the perimeter of the tunnel, which directly influences the cycle times of advancement. A quicker cycle time for each process is required to optimize the operation and therefore minimizing over-break is essential for operational success.

Jan 1, 2015

By R. R. Joseph, K. A. Gschneidner

The solid solubility of magnesium in the close-packed modifications of lanthanum, cerium, praseodymium, neodymium, gadolinium, dysprosium, and lutetium was determined from approximately 250°C to the eutectoid temperature by the X-ray parametric technique. The maximum solubility at the eutectoid temperature was found to be 9.4 at. pet in La, 8.2 in Ce, 9.2 in Pr, 8.2 in Nd, 14.1 in Gd, 13.5 in Dy, and 11.5 in Lu. The solubility when compared at a homologous temperature was found to increase in a smooth manner with decreasing size factor from lanthanum to lutetium. It was found that the apparent atomic radius of magnesium when dissolved in the lanthanide solvent was constant and could be accounted for by consideration of several models dealing with departures from Vegard's law. The eutectoid temperatures for the lanthanide-rich La-Mg, Ce-Mg, and Nd-Mg systems were found to be 544", 505°, and 551°c, respectively. A study of the solid solubility of magnesium in the lanthanide metals was initiated because the valency and electron egativity difference are essentially constant and favorable for solid-solution formation, and thus one could examine the effect of size on terminal solid solutions. The size factors based on metal radii range from 14.6 pet for lanthanum to 7.5 pet for lutetium. Since the electronegativity difference is small, 0.06 unit or less, application of the Hume-~othery' and Darken and Gurry2 criteria for solid-solution formation indicates that the solubility of magnesium would be expected to be small for lanthanum (between 5 and 10 at. pet) and to increase as we proceed along the lanthanide series. A search of the literature revealed no data on the solubility of magnesium in the lanthanide metals except for the solubility of magnesium in cerium at 450oCA typical phase diagram for the lanthanide-rich end of the lanthanide-magnesium phase diagram is shown in Fig. 1. EXPERIMENTAL PROCEDURES Preparation of Alloys. The lanthanide metals used in the preparation of alloys for this investigation were prepared from the corresponding fluoride by metallothermic reduction techniques previously described by Daane.4 The chemical analyses of the metals used are listed in Table I.

Jan 1, 1965

By Anna M. Ferrero

Stability condition of underground excavations have to be assessed to guarantee safe operations within the quarrying working areas. This objective requires a reliable assessment of the rock mass natural state of stress and of the stress redistribution induced by the excavations. This goal is often complicated by difficult geological conditions induced by tectonic stresses, complex topographies and large and irregular excavation geometries. Consequently, the acting state of stress needs to be measured by specific in situ measurement devices. This work refers on an in situ measurements campaign carried out by CSIRO tests in an underground quarry located in the Carrara marble basin. The difficult path carried out for interpretation of the measurements is described in this paper. In particular, the numerical modeling performed using the Boundary Element Method (BEM) first, to study the influence of both surface topography and excavation geometry and then the Distinct Element Method (DEM) to evaluate the influence of rock discontinuities in the measurement zone are illustrated in this work. Parametrical analysis of the rock mass mechanical features is also described in order to calibrate the numerical models and analyze the experimental results. The work has been carried out trough several phases, which are: characterization of the rock mass through geostructural surveys: this allowed us to classify the rock mass and determine the mechanical and physical parameters necessary for modeling; on-site measurement of stress levels through the application of over coring techniques; numerical analyses for the simulation of excavation phases, using the Examine3D (BEM) engineering analysis code. comparison between the measured stress levels and those numerically calculated and subsequent calibration of the BEM model; Numerical model of the forecasted excavation based on the calibrated (BEM) model.

May 1, 2009

By R. A. McIvor, R. Levac

"The Stobie No. 7 shaft, 14 ft diameter, double- drum skip hoist, was installed at the INCO Limited Frood Stobie Complex in 1942. Figure 1 shows the hoist layout. The hoist was originally equipped with babbitted journal bearings on the main drum shaft and pinion gears. In 1990, the hoist was modernized with a new braking system, two new 2000 hp D.C. drive motors, a thyristor armature supply and a PLC control system. The new drive motors were connected to the drive pinion gears with a gear type flexible coupling. The pinion gear journal bearings were refitted during the refit in 1990 as the existing babbitted bearings showed signs of wear. The pinion gear journal bearings had always run warm and had external cooling applied during the warm summer months. Figure 2 shows the journal bearings on the pinion shaft. The skip hoist main bull gear and two pinion gears were replaced in 1997 because of cracked bull gear spokes. New drive couplings were installed on the pinion gears and the pinion journal bearings were modified to allow some self-aligning properties to try to reduce the heating and wear on the babbitt. The modifications did not significantly reduce the heating problems and a decision was made in the spring of 1998 to convert the bearings to self-aligning, anti-friction-type bearings.The traditional roller bearings used on double helical pinion drive gears in hoist applications has always been double-row spherical roller bearings due to their high load-carrying capacity and misalignment allowances.Unlike single helical gears, double helical arrangements do not exert axial thrust on the pinion gear bearings, therefore, both bearings in the pillow blocks must float easily with any pinion displacement. Drum misalignment, thrust bearing end play and a multitude of other influences causes continuous axial displacement of the pinions when in operation. This constant displacement or “hunting” of the pinion gear to maintain its centre on bull gear often exceeds the axial clearance limits of spherical roller bearings thus resulting in a continuous sliding motion of the bearing outer rings against the housing seats. With time, the housing fit eventually wears, creating an out-of-round condition for bearing housing (maximum allowable cylindricity tolerance is IT4/2). When this happens, the pillow block housings must be replaced or re-machined to specification. Premature bearing wear and overheating will occur if a housing out-of-round condition is encountered."

Jan 1, 2001

By D. M. Fraser

"Brunswick Mining and Smelting Corporation Limited operates two mines; one open pit (No. 6) and one underground (No. 12), approximately 20 miles south-west of Bathurst, New Brunswick. Both are massive sulphide deposits containing copper, lead, zinc and silver. The No. 12 property began operation in 1963 and is presently being mined at a rate of 3600 tons per day underground and is in the completion stages of an expansion to achieve 11,000 tons per day underground by the end of 1930.Originally at Brunswick Mining, acid mine drainage was added to tailings and neutralized by an excess of lime in the tailings. A conventional recycle system was established with a biostabilization pond for the treatment of thiosalts, a liming station and sludge settling area for neutralization of acidic water and a final reclaim pond with a pumping station for reclaim water.We found that not more than one third of the reclaim water could be used as it upset the flotation circuit every time it was used. It was established that the mine water and surface drainage were the cause due to oils and detergents in the water. It was also found that the biostabilization pond method Cf thiosalt treatment was not efficient for year round operation in our climate.In 1974, we reviewed the problems and began a 3 phase program to control effluents from the property:"

Jan 1, 1980

In the spring of 1944 the Congress passed Public Law 290 (58 Stat. 190, 30 U. S. C. Sec. 321) "authorizing the construction and operation of demonstration plants to produce synthetic liquid fuels from coal, oil shales, agricultural and forestry products, and other substances, in order to aid the prosecution of the war, to conserve and increase the oil resources of the Nation, and for other purposes." Section 2 reads: "In order to carry out the :purpose of this act, the Secretary of the Interior is authorized- (a) to conduct laboratory research and development work, and, with pilot plants and semi-works plants, to make careful process engineering studies, along with structural engineering studies, in order to ascertain lowest investment and operating costs necessary to determine the best demonstration plant designs and conditions of operation;

Jan 1, 1948

By H. Hearnden

Whereas in the past, ladles were simply a means of transferring molten products from furnace tapholes to points of discharge be they casting pans or waste dumps, the ladle is now becoming a more integral and versatile piece of equipment in the pyrometallurgical plant. The drive behind this development is the need for continuous improvement in performance where better, faster and cheaper means remaining competitive in the global market. This paper will explore the technologies available for the rendering of a costly and otherwise cumbersome piece of pyrometallurgical equipment more efficient and versatile in adding value to the final product. Essentially it all revolves around heat and more importantly the loss of it when tapping. The common practice is to move the molten product to its point of discharge quickly with the minimum of interruption to prevent skulling and hence the cost associated with clearing it. The advances in Oxy-fuel burners, AC or DC ladle furnaces, converters, gas purging and high velocity, bath injection systems has increased the versatility of processes and enhanced the potential for adding value to intermediate products through down stream practices such as granulation and atomisation.

Jan 1, 2004

By Congcong Chen, Bo Ma

When assessing the safety of a tailings dam, the constant weight method (CWM) is one of the most commonly used methods. However, when the evaluation indicator value suggests serious defects, the evaluation value is often inconsistent with the actual situation. To address this issue, the variable weight method (VWM) is introduced to assess the safety of the tailings dam. Initially, a three-layer indicator system for dam failure safety assessment is built, and individual indicator values are divided into four grades. Then, an appropriate state variable weight function is constructed and relevant parameters are determined. Finally, a case study is illustrated to verify the effectiveness of the model. The assessment results of the VWM more closely represent the actual situation than that of the CWM, which is more helpful for decision makers and technicians to take scientific and reasonable precautionary measures, thereby improving the safety management of the tailings pond.

Oct 8, 2022

By James W. Bass

Introduction Atmospheric fluidized bed combustion (AFBC) is an improvement over coal-fired boiler design. It offers several advantages over conventional boilers. AFBC can meet sulfur and nitrogen oxide emission regulations without the need for add-on flue gas treatment equipment. The relatively low combustion temperature inhibits ash melting, thus reducing slagging and fouling that can in turn increase a boiler's fuel flexibility. AFBC process The fluidized bed boiler that operates at atmospheric pressure on the fire side (AFBC) is relatively simple and no different in purpose from those pulverized coal boilers used by utilities today. Fluidized bed boilers can generate steam at the pressure and temperature needed by modern steam turbines. Only the firing system is different. In fluidized bed combustion, the fuel can be almost any coal or waste fuel. It is burned in the presence of a bubbling bed of limestone. Air is forced through the bed at a velocity sufficient to support the weight of the bed particles. When the bed is fully fluidized, it bubbles like a boiling liquid. Although the burning coal makes up less than 1% of the fluidized bed, all the bed particles are heated quickly by the turbulence. The calcium in limestone reacts with sulfur dioxide produced in coal combustion to form calcium sulfate in a dry solid state. In this way, sulfur emissions regulations can be met without installing flue gas desulfurization equipment. Boiler tubes submerged in the bed absorb heat directly from the turbulent solids. The heat converts water in the tubes to steam or superheats the steam. Because of the intimate contact of the boiler tubes with the fluidized bed, heat transfer is highly efficient. Consequently, less boiler tubing surface is needed to generate the same amount of steam as in a comparable pulverized coal boiler. The optimum temperature for sulfur capture is relatively low, about 815°C (1500°F) as opposed to 1370°C (2500°F) for pulverized coal boilers. This results in the formation of lower levels of NON. Because operating temperatures are below those that fuse coal ash, a single design can burn a variety of coals without slagging or fouling problems. TVA's AFBC development program Tennessee Valley Authority's (TVA) involvement in AFBC development began in 1974 and has addressed the technical uncertainties through a comprehensive program of design, experimental, and analytical studies. In 1979, TVA and the Electric Power Research Institute (EPRI) developed plans for a 20-MW AFBC pilot plant, a 10-fold scale-up over the next largest test facility. Pilot plant design features TVA constructed the pilot plant at the Shawnee Steam Plant near

Jan 4, 1986

By E. J. Matson

"The Bureau of Mines has been investigating deposits of critical and essential minerals in the United States since 1939. Projects were set up on only the most promising properties.A preliminary examination of the Mount Hope mine was made in January 1943 by the Bureau's engineers, who recommended exploration by diamond drilling.The mine is in the unsurveyed portion of T. 22 N., R. 1 E., Mount Diablo base and meridian, south-central Eureka County, Nevada, 25 miles by road north of the village of Eureka. A partly graded and Graveled secondary road connects the mine and Eureka on U. S. Highway 50.Extensive sampling was done by the Bureau in February. 1943. Core drilling from the surface was started on March 15, 1944, and completed on April 2, 1545. The 16 holes drilled totaled 7,215 feet. The mining company also did extensive underground core drilling from April 21, 1944, to January 4, 1945. This report gives the results of core drilling supervised by the Bureau of Mines.The drilling program was designed to explore for extensions of the mineralization exposed in the mine workings. As a result of drilling, additional ore was found, and it is believed that this project has fulfilled the purpose for which it was planned.In its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization, of our mineral resources to the end that they make the greatest possible contribution to na¬tional security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples of ore and performs beneficiation test. Both these branches are under the supervision of Dr. R. S. Dean, assists director.With respect to this report special acknowledgment is due to Charles W. Merriam of the United States Geological Survey for his interpretation of the Mount Hope mine Geology and his cooperation throughout the project; Col. Leverett Davis, former lessee of the property; K. K. Hood, manager of the Mount Hope Unit, Callahan Zinc-Lead Co., Inc.; C. P. Knaebel, assistant manager, and M. P. Nackowski, geologist, of that company, for their help, and to the Sullivan Machinery Co. for its assistance."

Aug 1, 1946

By W. Lee Daniels

Significant deposits (> 4,000 ha) of heavy mineral sands were discovered in the USA Coastal Plain of Virginia and North Carolina in 1989. The majority of these lands support highly productive row crop agriculture, and the development of restoration protocols that would return these lands to agricultural use was deemed to be critical to the long term sustainability of mining operations. Virginia Tech worked closely with all stakeholders to develop appropriate restoration protocols and to coordinate their implementation. Full-scale mining operations at the Old Hickory Project in Virginia were initiated in 1997 by Iluka Resources Inc., and restoration protocols have continued to evolve in response to a variety of economic, technical, and social issues. Approximately 750 ha of land are in various phases of backfilling and final reclamation. Return of these lands to agricultural row-crop production has been complicated by lateral variability in mine soil physical conditions, excessive compaction, and limited topsoil return. However, within the past two years, a series of tailings deposition and soil reconstruction practices have been developed and implemented that significantly improve post-mining soil productivity. Deep ripping and appropriate use of organic soil amendments have been particularly effective at restoring post-mining soil productivity.

Jan 1, 2005

By W. Robert Thompson

Hurricane Katrina caused significant damage to transportation structures on the Gulf coast in August, 2005, including the destruction of the US 90 Bridge over Biloxi Bay, Mississippi. Part of the successful design/build proposal for the replacement bridge included a comprehensive test pile program of indicator piles and load test piles in the geotechnical investigation program. A total of 22 indicator piles were installed on the project using the pile driving analyzer to monitor the pile behavior. Five load tests were performed: two axial Statnamic, two lateral Statnamic, and one static axial. The results of the test pile program established driving criteria for production piles that included end-of-drive blow counts and pile tip elevations with an appropriate allowance for setup. The program also confirmed that the planned installation equipment and techniques of GC Constructors, a joint venture of Massman Construction Co., Kiewit Southern Co., and Traylor Bros., Inc., would install the piles to the design tip elevations before production piles began. An extensive program of restrike measurements at a range of times after initial driving of the indicator piles provided a systematic documentation of pile setup in the soil profiles on the site. These resistance values were used to develop a dimensionless setup factor ?S? as the ratio of the restrike resistance to the end of drive resistance. This factor varied from 1.5 for piles penetrating clays and tipped in sand to 3.0 for piles bearing completely in clay and helped establish an end-of drive blow count that included an allowance for setup. The CAPWAP analyses of restrike data with setup and the load test data were used to confirm the design unit side shear and end bearing values developed from the borings and static capacity calculations and to select the design pile lengths.

Jan 1, 2009

By J. B. Fletcher

The Miami mine first started operations in 1910. For convenience, the history of the orebody can be divided into the following categories (Fig. 1): 1) 1910 to 1925: 24.4 million tons of high grade ore, mined by top slicing, sublevel caving, etc. 2) 1926 to 1954: 102 million tons of low grade ore, mined by block caving.

Jan 1, 1961

By D Chalmers, C R. Ward, B B. Beamish

Coal workers’ pneumoconiosis (CWP) has re-emerged as a major concern in the Australian coal mining industry. Harmful effects from coal dust inhalation have been well documented, but the underlying causes and mechanisms of CWP are still debatable. Research conducted in the USA has proposed a plausible link between the presence of pyrite in coal and the prevalence of CWP. Reactive pyrite in coal oxidises under ambient mine conditions to produce various iron sulfate minerals such as melanterite, rozenite, roemerite and szomolnokite. Rapid reaction rates are promoted by the form (size and morphology) of the reactive pyrite present, which provides both increased surface area and increased porosity for easy air access to reaction sites. The products formed from reactive pyrite oxidation are often needle-like crystals with thicknesses in the order of 1–2 µm (eg melanterite and rozenite) and prismatic crystals with thicknesses less than 5 µm (eg roemerite) have been recorded. The densities of these minerals are significantly less than quartz, which makes them prone to becoming airborne with the normal coal dust. In fact, the mix of these mineral salts is commonly referred to as ‘fairy dust’ by mine workers due to the way they can become entrained and sparkle in the mine ventilation air, particularly if they occur in the upper part of a seam that is forming a coal roof. Examples are presented of the various products of reactive pyrite oxidation found in three Australian coal samples, which provide evidence of the physical and chemical mechanisms that would support the USA findings, particularly in terms of a source of bioavailable iron leading to increased inflammatory stress response.CITATION:Beamish, B B, Ward, C R and Chalmers, D, 2017. Products of reactive pyrite oxidation in the mine environment – implications for coal workers’ pneumoconiosis, in Proceedings Australian Mine Vent Conference 2017, pp 87–92 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

This paper gives a general description of mining operations at the Mount Morgan Open Cut. Certain features such as blast hole diamond drilling, which may be of particular interest, have been described in detail. The paper is covered by the following headings:-1. History2. Ore Reserves and Production Data3. Mining Methodsa. Design and Layout of the Open Cut.b. Overburden and Ore Breaking.c. Loading and Transport of Ore and Overburden.d. Transport of Men and Supplies.e. Survey and Assay.f. Drainage.4. Power and Compressed Air5. Mining Equipmenta. Shovels.b. Mine Transport.c. Dozer Tractors.d. Drill Shop.6. CostsHISTORYIn order to appreciate fully the design of the present Open Cut at Mount Morgan, a brief outline of the Mine's history and past mining methods is necessary. In 1882 the Mount Morgan Syndicate began to mine this large gold-copper orebody by small hill-top quarries...

Jan 1, 1952

By A J. Cornah

Critical decisions in iron ore project evaluation and production are based on global and local spatial estimates of primary mineral deposit properties (such as in situ geochemical grades) and geometallurgical responses (such as screened, washed or concentrated product yields and grades), which are derived from limited sample data. These spatial estimates are typically made using classical geostatistical techniques, which fundamentally assume that the attributes of interest behave additively. This assumption is generally appropriate for æprimaryÆ variables but æresponseÆ variables may behave non-additively and therefore their direct linear estimates may be biased.In this paper an existing additivity testing mechanism is used to quantify the bias resulting from direct linear estimation of a non-additive iron ore attribute. Data from a magnetite project are used to determine the circumstances under which such biases may be of material impact. The implications for iron ore resource estimation, geometallurgical modelling and grade control are outlined and discussed.CITATION:Cornah, A J, 2013. Assessment of the impact of non-additivity in the estimation of iron ore attributes, in Proceedings Iron Ore 2013 , pp 129-136 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013