Search Documents

By A. C. Nixon, A. D. S. Gillies, Hsin Wei Wu

Ventilation and refrigeration strategies for the 3000/3500 orebodies, Mount Isa Mines, Australia were reviewed. The orebodies lie between 1,200 and 1,800 m below surface and are characterised by steep geothermal gradients, intensively mechanised stoping methods and high ambient air temperatures in summer. Providing acceptable working conditions under these situations is difficult and costly. The ventilation air quantity required in the 3000/3500 orebodies exceeds 550 m3/s when the production rate is greater than 2.5 million tonnes per year. The maximum quantity that can be supplied and exhausted using the existing intake and return ventilation system is estimated at about 630 m3/s. For production rates greater than 3 million tonnes per year, either new intake and return airways will need to be developed or innovative approaches such as controlled partial recirculation used. A description is given of technical and economic investigations conducted at Mount Isa into controlled partial recirculation. During these investigations, a major field trial of a controlled partial recirculation system was undertaken with results indicating that an acceptable working environment can be achieved practically and economically utilising this approach. The cost involved in controlled partial recirculation for supplying the required ventilation quantity when the production of 3000/3500 orebodies exceeds 3 million tonnes per year is examined. A cost comparison between recirculation and other conventional alternatives such as new surface shaft or underground booster fans is included. The results indicate that the option of a new surface shaft will incur a high initial capital cost and moderate annual operating costs. The alternative of underground booster fans will necessitate a moderate capital cost and very high operating costs. Controlled partial recirculation, in this case, offers both the lowest capital and operating costs of the three options evaluated.

Jan 1, 1995

By A. D. S. Gillies, A. Haghighat

"A study has been undertaken at the Missouri University of Science and Technology (MS&T) limestone Experimental Mine to determine new fans set up and wiring options.to install additional mine ventilation capacity. Selection for main fans has been undertaken according to the mine’s required performance specifications and fan characteristics. Available fans for ventilating the mine are Joy and Alphair axial fans each of 24 kW each and two Spendrup booster fans of 12 kW each. The installation of main mine fans on the surface and underground entails numerous considerations. Design of a ventilation network for the Experimental Mine incorporating surface and booster fans has been accomplished using Ventsim Visual program software. The ventilation network has been separated into two segregated parts. A main surface fan and a booster fan have been used in each segregated part of the network. The mine has had a vane axial Joy fan in place for many years. The Alphair 4800 VAX 1800 full blade adjustable pitch vane axial fan was selected and installed as the other surface fan and eventual replacement for the Joy fan. Main surface fans have been connected individually to booster fans in series. The Alphair main surface fan has been installed vertically. Four different wiring options and related cost estimations for addition of the new main fans to the ventilation network have been considered. The analysis resulted in an innovative steel frame design used to allow the fans, when necessary, to be moved to the side of the shaft so that blast pressures do not damage the blades. INTRODUCTION Main fans are the heart of a mine’s ventilation network and play a key role in supplying required airflow (Haghighat, 2014). The Missouri S&T Experimental Mine has been developed in uniform limestone with few stratigraphic features. The mine floor is approximately horizontal and water drains well. A study has been carried out on MS&T Experimental Mine. Selection of main fans has been undertaken according to the mine’s required performance specifications and fan characteristics. Ventsim Visual computer simulation has been used to assist in design of the ventilation network. Wiring circuits, fan foundations and flexibility have been considered as the three main parameters for surface fan installation at the Experimental Mine. Two surface and two underground wiring options and three surface set up options and related cost estimates for the new surface fan system were investigated. Frequent use of explosives in the mine occurs throughout each year. Flexibility in changing the position of a surface fan is important. A number of options have been considered for the location of a vertical main fan positioned on the upcasting shaft. The mine is used for a variety of purposes and flexibility has a high priority amongst design considerations."

Jan 1, 2015

By Bekta? Uz

Istanbul is the bigest metropolitan city of Turkey with more than 15 millions of population and construction activities are steadly increasing with respect to that increase in population. In this papaer petrographical, physico-mechanical properties of natural aggregate mines from west, (Tekirdag) to East, Izmit (Gebze) 'will be summarized in connection with the concrete production. However the locations suitable for aggregate production in these area as; Paleozoic aged sandstones (Ayazaga, Cendere, Mahmutbey areas), Permb-Carboniferous aged limestones (Cebeciköy area), Triassic limes tones (Ömerli-Gebze areas) and Eosen limestones (Çatalca area), Plio-Quaternary aged volcanic basalts (Tekirdag, Çorlu, Beykoz areas). Plio-quaternary aged, fine grained aggregates within sandy formations are mined in Silivri-Sinekli area, Catalca-Ormanali area, Agacli-Akpinar (Kemerburgaz area) and Sile-Karakiraz-Sahilköy areas. Sandstones mineralogically contain mainly of Quartz+Feldspar and less amount of Mica (biotite+muscovite) rich with slica content and sedimentary origined. Especially limestones are cryptocrystaline textured, unique mineral composed of calcite and secondary have Dolomite ± (Quartz+Albite). Basalts are microlitic textured and contain Olivine+Pyroxene+Plagioclase. Chemically basalts rich with Fe and Mg and also volcanic origined. Sands are fine grained natural aggregates mainly contain semiangled, rounded minerals and rock fragments. Mineralogically have Quartz + Feldspar ± pyroxene+ ambhibole ±garnet and less amount of epidote ± magnetite ± hematite. Different rocks, used in aggregates such as limestones, sandstones-sands and basalts, supply varied concrete strength because of their mineralogical composition and characteristics of textures. Moreover, Basalts (Karatepe area) are good example for the higgest concrete strength (1017-1895 sc; kg/cm2) in our study area because of their clambed mineralogical apperance such as intersertal texture. As the result of extensive field and comparative laboratuary studies, the effect of petrographic, physical, mechanical properties of the aggregates on concrete srtength is extensivelly discussed in this paper.

Jan 1, 2005

By Theodore H. Eyde

In the southwest porphyry copper province, the virgin prospect with good copper mineralization cropping out has disappeared. Future discoveries will require an increasingly sophisticated arsenal of exploration techniques and concepts. One of the latter, stratigraphic analysis, is a technique which is often overlooked. A surprising number of exploration geologists still think of porphyry copper deposits as occurring wholly within intrusive bodies such as quartz monzonite or granodiorite. Disseminated copper mineralization, though genetically related to intrusive rocks, can occur within both the intrusive and the intruded rocks. At present, as much as 30% of the total copper produced from disseminated copper deposits in the Southwest originate from the intruded rocks rather than the intrusive. George M. Schwartz, in "Geology of the Porphyry Copper Deposits of Southwestern North America" points out that the host rocks at porphyry copper deposits include such diverse rock types as diabase, granite, limestone, dolomite, quartzite, skern, sericite schista, and others in addition to the more common monzonite, quartz-monzonite, and diorite porphyrys. Therefore, a porphyry copper can be defined as a disseminated copper deposit occurring either in or adjacent to a granitic-monzonitic-dioritic intrusive which can be exploited using bulk. mining techniques. The original definition of porphyry was originally applied to the early producers, such as Inspiration, Bingham, and Ajo, in which the copper mineralization occurred principally within the intrusive. A review of the geologic literature describing the porphyry geologic

Jan 1, 1971

By N. Lydakis ? Simantiris

Preliminary results of a mineralogical, geo-chemical and nutrient analysis of soil samples collected from Omalos polje-plateau are presented. This study is part of a project concerning the relationship of lithology and mineralogy characteristics of soils of different geological origin from the island of Crete with their chemical composition, and more specifically with their ionic nutrients content. The results presented in this work show a relatively good correlation of the mineralogy and the bulk content of the soils examined with the available nutrients in soil solution.

Jan 1, 2005

By K. C. Jordi

Many systems which are modelled mathematically result in a model where the relationships between some or all of the parameters are found to be non-linear. These systems are usually complicated further by a desire to make the system achieve multiple and often conflicting objectives or goals simultaneously. Rozwadowski (1970) developed a model to describe the total discounted net profit of a mine as a function of the amount of ore developed and of the grade of the amount of ore mined. Dynamic programming was used to determine the policy which gave the maximum net present value. In this paper it is shown that the relationships between the variables can be approximated by piecewise linear functions. This is amenable to solution by an algorithm based on the simplex algorithm of linear programming. The goals of maximizing the net present value, the total net profit and the total gold output are incorporated simultaneously into a goal programming formulation of the system. The resulting model is characterized by a large number of disconnected constraints. These are decomposed into several smaller problems and the problem solved. The solution is examined to discover the sensitivity of the system to changes in certain parameters. In particular the interaction between the three goals is analysed to determine whether there is conflict between any of the goals and, if so, what the trade-offs between the conflicting goals are.

Jan 1, 1979

By Kirk Carlton

This paper deals with a group of subjects so familiar to all of us that we might question the need for discussion. Even so, nearly every day's business turns up expensive examples of differences in understanding, misdirected assumptions and incomplete technical purchase documents. As our international activities increase, so do these problem areas. Their expense in both money and embarrassment gives rise to this attempt to focus a little extra attention on technical criteria and specifications. The two terms ?criteria? and "specifications" are, we believe, worth separating with respect to meaning. They should not be used interchangeably, although they often are. Criteria are by definition "standards for judging", whereas specifications are "enumerations of particulars". In relation to plant or project engineering, the criteria are the general rules and data which apply to the whole project and the specifications are the further listing of detailed requirements for specific contractual items or pieces of equipment. We'll look a little more closely at specifications after we give another minute or two to this "criteria" subject,

Jan 1, 1973

By Gordon R. Haworth

Conditions affecting minerals investments are continuing to change at an increasing rate, and in this paper we will attempt to predict the course of mine financing in the future. We will first review the situation historically and then examine the problems and constraints that are now making the financing task more difficult. Suggested solutions are discussed, and a new method of financing a group of mining projects is hypothesized.

Jan 1, 1977

By Kerstin Malmqvist

Simulation technique has been used for a feasibility study of a deep exploration project for massive, sulphides in an old mining district, the Skellefte field. An interactive computerized mathematical model of an ore field and a drilling procedure has been constructed. It is possible to represent varying geological structures. The model also takes in consideration economical factors such as drilling costs and ore values. On this model Monte Carlo simulations and probability calculations are done in order to estimate the outcome of different drilling strategies under varying geological assumptions. Under the specific conditions of the well known Skellefte field, it is found to be possible to even calibrate the mathematical model.

Jan 1, 1979

By George J. Bujtor, Anthony K. Scott, Haddon F. King

In 1982, the result of a 3-year study was published as "A Guide to the Understanding of Ore Reserve Estimation". The principal conclusions were that computation formed only part, and perhaps not the most important part, of an estimate and that the estimate should recognize that geological, mining engineering and metallurgical judgements formed an essential part of the eventual result. Subsequent expectation/realization studies of several mines have produced case histories which form the principal basis of the paper. These imply that geology is even a larger factor than thought earlier.

Jan 1, 1992

By P. D. Rao, D. E. Walsh, W. W. McClintock

A column flotation system was designed to conduct release analyses on a very finely disseminated, stratiform copper ore from the Denali Copper Prospect in Alaska. Chalcopyrite is finely disseminated in a carbonate matrix, and pyrite is disseminated in both the chalcopyrite and the gangue. Grinding to -20 µm is required for adequate liberation. A 25-mm x 2.4-m glass flotation column was designed. The ore and its flotation tailings were repeatedly floated to obtain a rougher concentrate. The rougher concentrate was then repeatedly floated to produce release fractions. These fractions were analyzed for copper, iron, calcium and magnesium, and release curves were plotted. The procedure was replicated at each of two grinds, i.e., 99% and 88% passing 37 µm (400 mesh). The procedure should find application for flotation characterization and process selection. Bond grindability testing was also conducted.

Jan 1, 1996

By D. L. Purcell, B. T. McClure, J. McDonald

The U.S. Bureau of Mines has completed a laboratory evaluation of exhaust emissions from a diesel engine using an oxygenated diesel fuel. The fuels tested were soy methyl esters in a neat (100%) form and low sulfur, petroleum number 2 diesel fuel (D2). The engine tested was a Caterpillar 3304, indirect injection, naturally aspirated, 75 kW, diesel engine that is typical of engines used in underground mining applications. The objective was to determine the extent to which oxygenated fuels, such as methyl esters, reduce diesel particulate matter (DPM), and their influence on upon gaseous emissions such as total hydrocarbons, CO, NOx, NO2, formaldehyde, and other exhaust emissions. Heavy- and light-duty transient tests were used to simulate load cycles typical of mine applications. The soy methyl ester fuel produced greater amounts of volatile DPM (organic material) but much less nonvolatile DPM (carbon soot) for overall DPM reductions. A diesel oxidation catalyst (DOC) typical of the type commonly used in metal and nonmetal mines was tested with both fuels. The DOC further reduced the volatile and total DPM when used with the soy methyl esters, but increased the total DPM for D2 due to sulfate formation. The soy methyl ester fuel reduced CO and hydrocarbon, and NOx emissions. The DOC further reduced CO and hydrocarbon emissions.

Jan 1, 1995

By Robert L. Sundeen, Richard V. Wenberg

INTRODUCTION Early rock-bolting practice usually consisted of ran¬domly installing bolts, using hand-held drilling equip¬ment such as air-leg mounted sinkers or stopers. As bolting technology evolved, the practice of installing uniform bolt patterns was developed, utilizing random bolt installation as required within the uniform pattern. The uniform rock-bolting technique, when used as the principal method of rock support, requires drills and jumbos designed specifically for rock bolting. This equipment is similar to conventional face drilling machines, except that the jumbos can orient the drills to obtain any necessary bolting angle; often, this means bolts may be installed at or near perpendicular to the centerline of the drift or stope opening. Fig. I shows a typical rubber-tired rock-bolting jumbo of the type commonly used in drifts and room-and-pillar mining. Modern rock-bolting jumbos are capable of drilling the required holes, inserting rockbolts, and torquing them to proper levels. Jumbos also are available for use with resin-anchored bolts. Probably the most unusual of this type utilizes a rotating bolt turret that carries the rock drill, resin charging unit, and the bolt in a single mechanism. Once the turret is loaded with the resin and bolt, further manual effort is not re¬quired. Drilling and bolt placement are accomplished by the operator from a station remote from the bolt site. Fig. 2 shows this turret device. Roof-bolting jumbos are available mounted on rail, crawler, or rubber-tired chassis. Various types of rock drills are used. Depending upon the type of rock, these may include rotary, percussion, or rotary-percussion drills. Fig. 3 shows a typical rail-mounted jumbo. CONDITIONS INFLUENCING APPLICATION General Rock Conditions Rock-bolting generally is applicable in moderately hard to hard rock. No particular type of rock is ex-

Jan 1, 1982

By Thornton L. Neathery

A small area in the Alabama Piedmont was studied to determine if metallic enrichment was associated with local magnetic anomalies. Cores from two holes in these magnetic anomalous areas have sulfide (pyrite, pyrrhotite, chalcopyrite) film on slicken-side and fracture surfaces. Two hundred and fifty soil samples were collected from the top of the "B" horizon on 1, 000 foot centers over the general trend of magnetic anomalies. Soil samples were leached with a 1:2. 7 mixture of HF and H2SO4 and the dilute filtrate analyzed for Cu, Pb, Zn, Ni, Co, Cr, Mo, and Cd, using atomic absorption methods. Concentration-value maps were prepared for each element. Small areas of anomalous concentrations were defined for Cu, Pb, Zn, Mo, and Ni. Some of these areas generally coincides with magnetic anomalies. Concentration values (ppm) range from: Cu 165.0 - 0. 5; Pb 265. 0 - 0.0; Zn 1386.0 - 43. 0; Ni 187.0 - 10.0; Co 207.0 - 6. 5; Cr 117.5 - 2.0; Mo 95.0 - 0.0; and Cd 32. 5 - 2.0. Studies of other magnetic anomalies appear warranted.

Jan 1, 1972

By J. D. Miller, C. L. Lin

A PC, image-based, on-line instrument for measuring coarse particle size on a conveyor belt is under development. The hardware and software required to implement such a system are discussed, including the interface for the special image-acquisition hardware. The system concept is given with examples to illustrate the step-by-step procedure for the implementation of image-processing algorithms.

Jan 1, 1994

By M. J. Mrugala

Typically the conventional pillar design methods consider the behavior of the pillar alone. In such analysis the contribution of the associated roof and pillar is not considered. The focus of this paper is a study of pillar behavior in the context of interaction between a different rock material sequence in the associated roof and floor. The finite difference element code FLAC (1)is used to perform modeling of pillar response to various stratigraphic sequences.

Jan 1, 2003

By Jeff W. Butwell

Mill flotation tailings impounded at the Gooseberry Mine site between 1976 and 1984 were determined to be an economic source of gold and silver recoverable by standard heap leach technology in conjunction with feed agglomeration. Metal recovery at 85 percent Au, 75 percent Ag is attained on properly agglomerated (pelletized) tailings which average 85 percent -75 micron. Because the impounded tailings averaged over 18 percent moisture (32 percent moisture maximum at depth) in place behind the storage dam, the mining method, mixing and agglomeration technique, and materials handling practice were major considerations in making this operation a financial success.

Jan 1, 1990

By John O. Marsden

The project development metallurgist is faced with an interesting dilemma: The use of overly conservative metallurgical projections and cost estimates can kill a project that has the potential to provide needed jobs and growth to a company's bottom line. On the other hand if the metallurgist uses a highly aggressive approach by trimming capital and operating cost estimates to the bone and by applying highly optimistic metallurgical projections, there is a risk of creating a project that can never live up to expectations. The metallurgist must walk a tightrope between "sandbagging" and "overoptimism," and this tightrope is fraught with political intrigue and difficulty. This paper takes a some- what lighthearted look at some of the political aspects associated with this issue, and other issues, and offers a few guidelines for walking the "political metallurgical" tightrope.

Jan 1, 2001

By James R. Tompkins

This paper details the successful progression of a promising exploration property into a producing gold mine in only 35 weeks on schedule and on budget. While under construction, an extensive exploration program continued to add to the mine life through the increase in reserves, resulting in a decision to increase the mill capacity from 500 tonnes per day to 1000 tons per day while maintaining the original construction schedule. Details are provided on the unique geology at the Puffy Lake Gold Mine, development from the exploration stage through construction and ultimately to production, with a detailed flow sheet. In addition, of note is the successful change over from contract mining to the hiring of Pioneer personnel who are successfully carrying on both stope mining and development. Operating costs per ounce of gold production are projected at $185 U.S. and alternate methods of mining are currently being examined which could further reduce operating costs.

Jan 1, 1988

By Kenneth R. Miller

Surface mine equipment operators in the Campbell County region of Wyoming's Powder River Basin have found new ways of solving old problems. Technology, experience, competitive pressures and an increasing grasp of economies of scale have driven mine operators, equipment manufacturers and suppliers to specialization of applications. In economic terms, today's coal price of $4.95/t ($4.50/st) equates to $2.53/t ($2.30/st) in 1980 terms - an incomprehensible value at that time. This article describes some examples of change and adaptation made by Powder River Basin coal operators in overburden stripping equipment and techniques. It focuses on the evolution of the design and use draglines, shovels, trucks, scrapers and dozers.

Jan 1, 1998