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By Elmer A. Jones

Development work in mines of St. Joseph Lead Co., Southeast Missouri, using trackless loading equipment shows definite advantages: Speed of cleaning, ability to work on steep grades and sharp crosscuts, good later tracking conditions, and possibility of wasting rock in old abandoned stopes. THE Desloge mine is one of a group of mines owned by the St. Joseph Lead Co., in the so-called Lead Belt of Southeast Missouri. It has been operating approximately 40 years producing a daily tonnage ranging from 1600 to 3800, depending on various factors. On an average, the present mine is 300 ft deep with an extreme extent of 2.7 miles by 1.7 miles. Most of the present mining is in the lower horizons of the Bonne Terre dolomite, a fairly soft rock requiring no support except occasional channel iron and roof pins. Due to the contour of the underlying sandstone and porphyry, some development work has been through short stretches of these different formations. In some areas the lower part of the dolomite is quite sandy and generally is considered abrasive. Sizes and Methods of Drifting Have Changed: Development work has, like other phases of mining, changed considerably in the last 20 years, from cleaning by hand to the use of a mechanical method. The conception of a standard drift has also changed. Before the advent of mechanical loading in stopes there were many pieces of main line drift averaging 7 ft high x 9 ft wide. With the coming of the St. Joe shovel the drift was increased to 8 ft high x 10 ft ELMER A. JONES, Member AIME, is Assistant General Mine Superintendent, St. Joseph Lead Co., Bonne Terre, Mo. AIME Columbus Meeting, September 1949. TP 2859 A. Discussion (2 copies) may be sent to Transactions AIME before July 31, 1950. Manuscript received Sept. 16, 1949. wide. Now with the Joy loader and shuttle car, a 9x11 ft drift is coming to be standard size. Methods of cutting drifts have changed considerably over the last few years. Some changes in drilling equipment have been made such as reducing the weight of column, clamp, air feed, and fittings to go with the HC10 Cleveland jackhamer. Other changes have been made in drill steel such as the use of detachable bits; throw-away variety, screw type, and the tungsten-carbide insert bits. Later developments have introduced spiral-welded pipe with victaulic couplings, millisecond exploders, bulky powder, and the use of electric cap lamps. Experimental work is going on continually in various phases of development work, some to be tried and discarded, others gradually to become standard practice. To sum up, the standard method of development now in use at Desloge is as follows: The work is done on a two-shift cycle 7:00 p.m. to 3:00 a.m. and 7:00 a.m. to 3:00 p.m. Two men known as development drillers comprise a crew on each shift. These two men arrive at their work about 7:30 to find a round blasted by the previous shift. After scaling down back and walls they proceed to the cleaning operation, using either a Joy loader and shuttle car, a drag hoist mounted on a slide ramp, or an Eimco Finlay to load into a 21/2 ton mine car. Cleaning may take from 2 to 4 hr depending on conditions such as length of round broken, length of haul, and other variables. After fitting up pipe and setting up columns and drills they are ready to drill a round which should measure 9 ft high x 11 ft wide and break from 5 to 7 ft advance. This may also take from 2 to 3 hr. Then they are ready to charge and

Jan 1, 1951

By Leonhard Schmid

INTRODUCTION In the region of Zurich several of the Swiss Interstate Highways meet and have to be linked to form a continuous network. The subalpine glacial topography with hills, ridges and lakes requires the construction of many tunnels (Figure 1). The Milchbuck Tunnel forms part of the inner arterial highway system of the city of Zurich. It passes underneath the ridge separating the Limmat and Glatt valleys. In its final configuration the tunnel will consist of two parallel three-lane tunnels (Figure 2). For the time being only one tunnel is constructed. This tunnel will be operated with two outbound (climbing) lanes and a single inbound (descending) lane (Figure 3). The owner, the Canton of Zurich, awarded the contract for the construction to a joint venture with the following three contractors: Locher & Cie AG (leader), Prader AG, A. Brunner's Erben, all located in Zurich. The actual freezing was performed by subcontractor Philipp Holzmann AG, Mannheim, West Germany. Electrowatt Engineering Services Ltd, Zurich, was design engineer and performed the construction supervision.

Jan 1, 1981

By A. G. Merma

In this work, the electrocoagulation technique was studied in order to treat chemically stabilized concentrated oil-water emulsions. This study was mainly focused on the effects of operating parameters such as initial pH, current density, reaction time, electrode distance and inlet concentration on the separation of oil as measured by the chemical oxygen demand -1(COD) method. The synthetic emulsion was prepared from Shell - Talpa 30 oil (3g.L-1) and sodium dodecyl sulfate (1.0 g.L), having a Zeta potential around -70 mv at pH 8.7. The process was carried out in an electrocoagulation cell with a set of four parallel monopolar electrodes. This set consisted of two aluminum plate anodes and two 316L stainless steel plate cathodes. Kinetic curves showed that the electrocoagulation process exhibits three phases: (1) an initial phase, where the COD did not decrease because the solution had not reached the minimum amount of dissolved aluminum required to cause the break-up of the emulsion, (2) a reactive phase during which COD decreased due to possible agglomeration of the precipitates and (3) a steady-state phase where the COD did not change. The results showed that the period to reach the reactive phase decreased as the current density increased and the pH values decreased.

Jan 1, 2009

By M. Elmadagli

Wear mechanisms of two commercial aluminum alloys, namely a spray formed and extruded Al-25%Si alloy, and a sand cast A390 alloy (18.5 %Si) that are known to be successful in cylinder bore technology were studied to have a better understanding of the requirements for wear resistant aluminum alloy design. From durability point of view these alloys are known to be successful for engine bore applications. It is interesting to compare the wear mechanisms in these alloys because they have significantly different silicon content and microstructures, and were produced using different techniques. The wear tests were done using a block-on-ring configuration, in controlled air atmospheres (5 % relative humidity). In spite of the differences in silicon content and microstructure, the wear mechanisms were similar and consisted of formation and destruction of hard tribolayers that are either formed by either mechanical or chemical interactions on contact surfaces. The differences in the wear rates between the two alloys arose from the differences in the hardness of the worn surfaces, and the alloy's ability to sustain the tribolayers on the worn surfaces.

Jan 1, 2004

By R. K. Singhal

Optimization of a load-haul system for a surface mine involves two processes. The first is proper selection of mining equipment compatible with the minesite job specifications and the second is an efficient utilization of this equipment. All things being equal optimal productivity and cost is achieved when the capacity of the hauling equipment is matched at all times with that of the loading equipment.

Jan 1, 1986

By K Barbosa, G Wilkie, F Reyes, V Jokovic, C Evans

The idea behind Grade Engineering is to exploit the natural heterogeneity of an orebody (spatial, temporal) in order to divert low-value waste out of the mining value chain. Essentially, this involves rejecting material at relatively coarse particle sizes (10 mm to 200 mm). However, lack of knowledge about the inherent particle grade distributions in these coarse particle size ranges limits the opportunities for optimisation. Particle grade distributions are essential for quantifying and modelling gangue liberation and yield curves. These curves can then be used to predict the mass and value flows that will go towards the accept and the reject streams. Particle grade distribution information for particles coarser than 10 mm can be collected based on chemical assays of sufficient number of individual particles. However, for smaller particles (1 mm to 9 mm), a significantly larger number of particles is required for assays. Moreover, in some cases, the mass of individual particles is smaller than the minimum mass required for chemical assaying. Also, other quantification techniques such as automated mineralogy, eg Mineral Liberation Analysis (MLA), require extended measurement times to analyse statistically representative numbers of particles at these size ranges. This work investigates the use of 3D X-ray microtomography to fill this quantification gap at these size ranges (1 mm to 9 mm). In-house image processing algorithms are used to estimate the mineral/metal content in each particle. Particle grade distributions, as well as density distributions, are thus produced without a minimum mass requirement and with each scan providing information about tens to hundreds of particles at a time. Mineralogical data from MLA analysis, of finer size ranges, is used to inform X-ray microtomography, so a simpler 3D mineral map can be obtained using the image intensity. Chemical assay information of the scanned samples is used to validate and correct the mineral phase segmentation.

Aug 24, 2022

By C. W. Owning

"The Bureau of Mines has repeatedly emphasized the necessity of completely ""rock-dusting all coal mines, except anthracite mines, in every part whether in damp or dry condition."" Every open accessible part of, the, mine without exception should be thoroughly rock-dusted, including parallel entries, air courses, trackless entries, crosscuts, and rooms to within at least 40 feet of every coal face. Very few mines have followed this recommendation and warning, with the result that there have been explosions not only in mines which have not used rock dust but also in so-called rock-dusted mines. Following a number of mine explosions it has been reported that the mine was rock-dusted,"" whereas it is probable that only some of the haulage roads had been given a hurried application of rock dust and in most instances not as much as 5 per cent of the mine was really rock-dusted. That is not rock-dusting.Some conscientious, well-meaning mining men have felt that rock-dusting of haulage roads would effectively stop an explosion; however, when shown, through widespread explosions in mines ""well rock-dusted"" according to the above method, that leaving large areas undusted, furnishes paths through which a violent explosion may travel, these mining men have realized the necessity of thorough rock-dusting and have adopted this explosion-prevention method.The Mather Collieries mine, Pickands, Mather and Co., operators, at Mather, Pa., was the first mine in Pennsylvania to receive, full credit for rock-dusting under the new 'stringent ruling of the Pennsylvania Compensation Rating Bureau, the provisions of which require that:"

Feb 1, 1931

The Silvermines area of north County Tipperary in Ireland has experienced mining activity for over a thousand years, with lead, zinc, copper, barite and sulphur being extracted from a series of Carboniferous limestones. The last mine to operate in the area was closed in 1993. A legacy of contamination and derelict surface structures remain. Following the death of cattle in the vicinity in 1999, a governmental Inter-Agency Group was established to conduct an investigation. The ?Silvermines Rehabilitation Project? resulted, and included a proposal for the development of a Mine Waste Management Facility (MWMF) to act as a repository for waste materials from problematic sites across the area. The nature of the setting supported an effective solution from both a cost and performance perspective; and with limited maintenance requirements. Locating the MWMF where most wastes were identified would help minimise handling and relocation of materials. This position coincided with an area of artesian groundwater pressures. The resulting MWMF design consisted of a perimeter engineered embankment with the crest elevation designed to just exceed the groundwater piezometric surface. The base would remain unlined and groundwater permitted to rise up into and saturate the contained in-situ tailings deposits and imported mine wastes. The proposed system thus benefited from the ?wet cover? approach to minimising further oxidation of wastes and metal leaching, but without the usual accompanying outward hydraulic gradient and leachate management issues. A sub cap drainage layer with downstream outlet was incorporated to prevent any possibility of hydraulic rupture following an unexpected rise in groundwater heads. Leakage rates from the MWMF were deemed to essentially be driven by surface infiltration rates alone (characteristic of a ?dry cover? approach), with the proposed composite capping system simulated to perform at an infiltration rate of less than 1 mm per year. A toe drain was incorporated with the perimeter containment system, and this collection together with diverted neighbouring drainage was directed under gravity to a dedicated Passive Treatment System (PTS). Overall, effluent water quality from the PTS has been predicted to reflect an annual mass metals removal in the order of 95% below baseline.

Aug 1, 2013

By W. A. Tiller, J. P. McHugh

HE majority of liquidus and solidus surfaces in phase diagrams have been determined by the conventional cooling- and heating-curve techniques.' These techniques have two main shortcomings: 1) the solidus may be in considerable error due to the difficulty involved in completely homogenizing the solid and 2) the determination of liquidus and solidus in more than a two-component system does not enable one to determine tie-lines connecting the specific equilibrium solid and liquid compositions. However, in a recent paper by one of the authors,' a method was suggested whereby the liquidus and solidus surfaces plus tie-lines in an n-component system may be determined. This method utilizes a controlled solidification technique and assumes that interface equilibrium exists during freezing. The present work was undertaken with a twofold purpose; first, to determine the liquidus and solidus lines in the pseudo-binary system Bi2Te3-Bi2Se3 by heating- and cooling-curve techniques and, second, to determine the partition coefficients of Te and Se in the BizTe3-,Sex system by controlled solidifica- tion techniques. The two sets of results can be compared to test the accuracy of the controlled solidification method. EXPERIMENTAL I—The starting materials for this study were 997999 pct Bi, Te, and Se, obtained from the American Smelting and Refining Co. The compounds BizTe, and Bi2Se3 were each prepared by melting together stoichiometric amounts of the elements, followed by twelve zone-refining passes. This produced homogeneous bars of the compounds for use in the phase-diagram studies. The apparatus used to obtain heating and cooling curves is illustrated schematically in Fig. 1. The alloy samples were located in a graphite crucible placed in a stainless steel canister. The canister was supported in a heavily lagged pit furnace by a device which oscillated the canister about its vertical axis at a frequency of about 3 cycles per sec during heating and cooling-curve runs. The graphite crucible was designed to minimize the thermal coupling of the sample to the furnace. A thin graphite sleeve separated the alloy sample from the stainless steel tube that housed the thermo-

Jan 1, 1960

By Carlos Alberto Silva

A aplicação de lubrificação de tiras é um desafio para a maioria das empresas. Aplicações irregulares, não uniformes e excesso de óleo são problemas típicos encontrados quando se utiliza rolos de transferência ou tubos furados. Outros problemas como névoa, baixa eficiência de transferência e um ambiente de trabalho perigoso e insalubre são problemas comuns encontrados com equipamentos que utilizam a pulverização atomizada. O atual trabalho busca comparar os resultados da lubrificação de tiras obtidos com um equipamento de pulverização hidráulica da Spraying Systems frente ao antigo equipamento utilizado, atomizado.

Aug 16, 2017

By Joseph J. Wallace

1. The Pittsburgh is the most important bed in Washington County from the standpoint of present production and recoverable reserves. 2. Known measured and indicated reserves in all beds, based on a minimum thickness of 14 inches and 1,800 short tons per acre-foot of coal in place, are estimated at 4,181 million short tons as of January 1, 1954. Of this total, 4,132 million short tons is in beds 28 inches and more thick. Areas in some beds were omitted from the estimate because available data relative to the bed characteristics are too meager for making an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves.

Jan 1, 1955

Jan 1, 1923

Jan 1, 1923

By Richard P. E. Hermsdorf

IN the nonferrous sessions this year, magnesium wiggled its way into a dace of prominence such as it has never before enjoyed. This was evidenced not only by the number of papers presented on that metal but by the attendance at the meetings. The atmosphere permeating these magnesium meetings was similar to that which exists in a family with a new baby. Everybody crowded around to see what it looked like and then wondered whether it would be a success and credit to the family. Well. magnesium appeared to be a vigorous youngster, full of life, and raring to go. A close relative of maenesium named " aluminum, although much more grown up, also attracted much attention. From the activity and spirit in these sessions

Jan 1, 1944

By Zhian Liang, Xiong Huang, Weixin Wu, Lifeng Cui, Zhuanhua Wei, Guoyao Li, Xiao Ni, Junrong Wang, Shuiping Zhong

ZJ 201 (modified starch) is a non-toxic, odorless, and biodegradable polymeric depressant, which selectively depressed galena in batch flotation tests while chalcopyrite was not significantly affected. In a plant trial, copper-lead separation was successful for the first time without using dichromate. Moreover, the plant process could be changed to sequential Cu-Pb flotation using ZJ 201 for higher grade lead concentrate. A copper concentrate was obtained with a Cu grade of 24.91% and a Pb grade of 5.11%, which recovered 76.6% of the copper from the original ore; a lead concentrate was also obtained with a Pb grade of 21.90% and a Cu grade of 5.31%, which recovered 52.6% of the lead. In addition to the effective copper-lead separation observed in the plant trial, another improvement observed is that gold was recovered mostly in copper concentrate, which could be sold for higher prices. Au grade reached 230.64 g/t, and its recovery reached 65.8% in the copper concentrate. Au grade in lead concentrate was only 18.90 g/t.

Aug 27, 2021

By Hu Meilong, Liu Lu, Bai Chenguang

Extracting perovskite from high titanium-bearing blast furnace (BF) slag is a green and potential method to recover the second titanium resource. The non-isothermal crystallization process of perovskite in synthesized high titanium-bearing slag was studied in situ by confocal scanning laser microscope (CSLM) with cooling rate of 20 K/min. The results showed that perovskite was the primary phase formed during cooling process in the titanium-bearing synthesized slag (TiO2=23%). Perovskite started to precipitate at 1719 K and finally presented an orthogonal straight lines morphology.

Jan 1, 2014

By Steve W. Ciccone

The Red Dog Mine is both the largest known zinc reserve and the largest zinc producer in the world. The mine started in 1989, and by 1999 had increased production from approximately 300,000 tonnes per year (t/yr) of zinc concentrate to in excess of 900,000 t/yr. The VIP Mill Optimization Project further increased zinc concentrate production to 1.1M t/yr while improving both product quality and zinc recovery. The Mill Optimization project also addressed a number of issues related to risk reduction: power generation capacity, water treatment capacity and concentrate thickening. The project was faced with numerous challenges, the most daunting of which was the schedule. This US$105M project was executed, from conception to completion, inside of two years. Less than nine months elapsed from concept to delivery of materials and equipment to site. The project also faced a 100-day icefree shipping window, the challenges of construction in an Arctic environment, and an extremely tight labour market for qualified craft personnel. These challenges were successfully addressed with several innovative approaches to project execution, including an Alliance contracting arrangement between the owner, engineer and contractor; full integration of the team; construction of modules in Anchorage; and fast-track engineering, procurement and construction. Steve Ciccone, AMEC?s project manager on the Mill Optimization project, works for the Mining & Metals unit of AMEC, a world leader in the provision of engineering and construction services. He obtained his BASc from the University of British Columbia and is currently midway through his MBA program at Simon Fraser University. Steve has 15 years of experience providing engineering and project management services on mining and metals projects, and has been involved in the execution of five capital projects and several studies at Red Dog since 1995. George Hope was responsible for process design and engineering on the Mill Optimization project and has been Manager, Project Development at Teck Cominco since 1995. Prior to this time, he was a project manager and chief metallurgist for Lac Minerals for 14 years and a mill superintendent and metallurgist for Noranda for 5 years. George received his BSc in Mineral Technology from the Royal School of Mines in England.

May 1, 2002

By Kerry Spickelmier

Editor's note: information for this feature was taken from the published APCOM proceedings. Computer trends, with special focus on the reasons for computer use, grabbed the lion's share of attention at the 23rd worldwide meeting on the Application of Computers and Operations Research in the Mineral Industry (APCOM 23). However, technical topics did not provide the meeting's sole focus. The last-minute inability of certain former communist countries to fund the travels of a few scheduled speakers was a reminder that science does not operate in a void. As with all technical progress, the APCOM presentations raised interesting questions regarding interrelated organizational dynamics and political and socioeconomic issues. Consider US Bureau of Mines (USBM) research to design an expert control systems to "duplicate" an experienced, "good" operator during automated underground roof bolting. In his presentation of the project, Takach, Jr. stressed the importance of preserving the ability to switch from automatic to manual drilling control. From a technical standpoint, this allows the expert system to "learn" from a good operator. As important, he said, is that this flexibility decreases the human operator's sense of being replaced by the machine. The question arises: Which will loom larger in union minds, increased operator safety through remote opera¬tion or the potential for total operator replacement? Like any new product, computer technology relies on marketing to aid its acceptance and use. Consider, too, a decision support system, by Schena and Gochin, for mineral resource management in a developing country. The authors said "the analysis permits the assessment of the overall socioeconomic consequences of mineral prospects and allows incorpo-

Jan 1, 1992

By Alan K. Burton

An industry-wide demand for bigger and more efficient trucks, with their supposed economies of scale, is well established. Some trucks have been, and often are brought "off the shelf," with the manufacturer offering only certain minor options, much as in the private automobile industry. The market is well established; there is keen competition; in recent years there have been few significant changes, and few are expected. With large trucks (100-ton-capacity and over), however, the situation is different. Here, with an individual truck costing several hundred thousand dollars, there is an ever in- creasing trend to engineer a truck for a specific application. The body will be designed and sized for the material that the truck will carry; the engine and transmission will be geared to the haul profile, and tires will be designed to suit road conditions and work requirements. Early Truck Development Haulage trucks designed expressly for open-pit mine service were introduced during the 1930's. The first models to arrive on the scene hauled about 15 tons, and easily outperformed the modified highway trucks that had been used for mine haulage up to that time.

Jan 8, 1975

By K. Ebrahimi-Nasrabadi

The dependence between the extent of conversion of cryptocrystalline magnesite to caustic magnesia was studied experimentally in the temperature range of 400?1200 °C and for calcination times up to 8 h. A TGA?DTA analysis showed that decomposition begins at temperatures as low as 340 °C and is completed at 600 °C. Measurements of specific surface area (SSA), iodine adsorption number (IN), crystallite size, and loss on ignition were carried out to characterize the product quality. It was found that while all the parameters are dependent on the extent of calcination, densification of the product caused by grain coarsening affects their final values. As a consequence, SSA and IN went through a maximum with time. The study showed that high quality caustic calcined magnesia can be produced in a narrow range of temperature (600?650 °C) and time (1?4 h). Medium quality caustic calcined magnesia can be made within a wider range of parameters.

Aug 1, 2013