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By Nils A. Eilertsen

This Bureau of Mines report describes the unit cost procedure for estimating direct development costs within a cave block in an undercut block caving mine. Costs of supervision, labor, equipment, and supplies are combined to build a unit cost for each type and size of mine development opening in the block. These costs are then combined to estimate the direct cost for developing a ton of ore. Operating data from several domestic metal mines are combined with a hypothetical mining system to illustrate the costing procedure.

Jan 1, 1975

By George J. Conroy

Results of a long-term program of electrical parameter measurement in under-ground coal mine working sections, performed by The Pennsylvania State University under U. S. Bureau of Mines sponsorship, are utilized as the basis for an analysis of the electrical energy requirements during operation. A model section is hypothesized, developed from the average or most representative characteristics as determined from tabulations of the measurements. Performance factors of the model section's machine complement are then analyzed, particularly with regard to the energy required per ton of raw coal cut and delivered from the section. Results are given in kilowatt-hours per ton.

Jan 1, 1977

By Art Hamilton

Abstract -The Zn-Pb-Cu-Ag ore deposits of the Boundary and N-5 zones near Bathurst, New Brunswick, occur in a polydeformed volcano-sedimentary sequence that is part of the Ordovician Tetagouche Group. Massive and disseminated sulfides are hosted by an argillaceous to cherty sedimentary sequence that is stratigraphically underlain by a siliceous fragmental unit and is overlain by a feldspar-rich crystal tuff and related tuffaceous rocks. The deposits have a low iron sulfide con­ tent relative to that of most stratabound sulfide deposits of the Bathurst-Newcastle mining district. The ore is commonly associated with chlorite- and talc-rich sediments. The N-5 deposit is considered to be the fault-displaced extension of the Boundary deposit. The Boundary deposit is estimated to contain 891 000 t grading 3.310Jo Pb, 7.96% Zn, 0.32% Cu and 44 g/t Ag; the estimate for the N-5 zone is 330 000 t grading 3.24% Pb, 7.15% Zn, 0.33% Cu, and 37 g/t Ag. The ore is processed at 1000 tpd at the Heath Steele mill.

Jan 1, 1992

By C. R. Kuzell

IN COMPARISON with recent years 1932 has yielded much less tangible evidence of progress in copper reduction and refining. The industry has been extremely quiet, especially in the United States. Design and construction has been throttled by lack of new capital expenditures. The excess producing capacity of the whole industry and the extremely gloomy outlook for the future have made it unwise to tie up more capital except under special conditions. The plants built during the previous year have, however, been placed in operation. Older plants have been abandoned, temporarily shut down, placed on part time operating basis, or continue to operate at a low percentage of normal capacity. In the United States the Phelps Dodge Corporation at Douglas, Ariz., has completed the remodeling of the former Calumet & Arizona smelter. A new roaster and Cottrell plant chimney was completed this year. Though operations have been limited the new equipment has been found to justify all expectations. The reverberatory plant addition consists of two furnaces 26 by 107 ft. inside dimensions, with a high arch, and modern steel binding of excellent design. Natural gas fuel gives good results. One of these furnaces will treat 1000 tons of solid charge per day with a fuel consumption of approximately 3,000,000 B.t.u. per ton. The larger converters have not only yielded the expected lower costs, but have simplified operations in the converter department. One of the noticeable results is the greater cleanliness in the environment and the absence

Jan 1, 1933

By S. Banisi

Thickening is the most widely applied dewatering technique in mineral processing. Thickeners are used to increase the concentration of suspension by sedimentation, accompanied by the formation of a clear liquid. As the particles get finer the thickening process encounters difficulty due to a significant change in the settling behaviour of particles. The batch settling tests of coal refuse of a coal washing plant which contained 91% particles smaller than 38µm and 0.6% coarser than 75 µm showed that the optimum feed percent solids that provided highest flux (solids handling capacity) was 4%. The flux of the pulp with the plant solids concentration (i.e., 10%) was 60% lower than that of the pulp with 4% solids. A thickener with a diameter of 22m based on the dilution of feed from solids concentration of 10% to 4% was designed. Monitoring of the thickener performance for a period of one month in the plant indicated that on average the feedrate of 25t/h (dry solids) with solids concentration of 10% could be thickened to the underflow concentration of 26.5% with a clear water overflow. It was found that the key component of the successful operation of the thickener is the dilution of the feed without which the overflow loses its clarity and the system ceases to operate under predetermined conditions. Specially designed feeding system which efficiently dissipated the energy of the incoming flow and staged flocculant addition regime are among the main contributing factors in making the design and operation of such thickener possible.

Jan 1, 2014

By F. D. DeVaney

In the course of the investigation by the U. S. Bureau of Mines and the Missouri School of Mines and Metallurgy at the Mississippi Valley Experiment Station at Rolla, Mo., on the beneficiation of the low-grade manganese ores of the country, some samples from the Cuyuna District, Linn., have been examined. The work was done under the direction of W. H. Coghill, supervising engineer of the Mississippi Valley Experiment Station. Joseph and Kinney in writing about the relative importance of Minnesota deposits of low-grade ore compared to the total reserves say: "***It has been estimated that 26 to 35 million tons of ore contain 5 to 35 per cent of manganese, and the total domestic tonnage is from 75 to 48 million tons. The mean of these values is 30.5 million and 42 million tons, so it is seen that about 75 per cent of the reserves are in Minnesota." The manganese-bearing ores of the Cuyuna district maybe roughly grouped into two classes. The most abundant ore is of the low-silica, low-manganese, and high-phosphorus type called brown are. The other type is the so-called black ore, which is characterized by a higher manganese and silica content and by a lowe phosphorus analysis than the brown ore. As a general rule the brown ore carries less than 10 per cent of manganese while the black ore contains about 15 per cent and sometimes as high as 22 per cent of manganese.

Jan 1, 1930

By S. S. Hsieh

Bench-scale beneficiation studies were made on Idaho dolomitic phosphate rock using the TVA carbonate flotation process. The process employed diphosphonic acid as a phosphate mineral depressant and fatty acid as a carbonate mineral collector. Silica was subsequently rejected as float using an amine collector, with phosphate product recovered as the sink fraction. Two samples of prepared flotation feed from commercial operation were used; one contained 21% P205 and 3.2% MgO, and the other contained 26% P205 and 1.8% MgO. The results indicate that concentrates containing 31-33% P205 and 1% or less MgO can be obtained, with P205 recovery of about 80%.

Jan 1, 1984

By Amir Zavichi

Today, with the necessity of timely, on-budget and high quality completion of projects, proper use of construction equipment is essential to ensure project success. Construction equipment places a large monetary burden on the project and if not utilized efficiently, it can result in economic losses. Cranes are one of the most important and expensive operational devices on construction sites. They play a central role, and often activities that rely on crane services fall on the project?s critical path. Currently, material-handling scheduling is done by the crane operator or by an on-duty superintendent using his/hers personal judgment, making the process manual and timeconsuming. Thus, developing an optimal schedule, which considers different dynamic constraints in construction job site, may not be possible based on the current practice. This leads to longer operation times and a negative impact on project cost. This paper presents the latest results of an ongoing study, which aims to design and implement a nearreal time crane operation decision support system to be utilized directly by the crane operator or as an aid for the superintendent in scheduling optimal operation services. This system has several advantages such as maximizing the efficiency of crane operations, guaranteeing the best operation possible to reduce the crane?s travel time, reducing crews and equipment idle time, and minimizing the dependence on subjective human judgments.

Aug 1, 2013

By K Peters, C McKenzie

New Zealand has an established history of gold production beginning with the gold rushes of the 19th century in the Coromandel, Nelson/Marlborough, West Coast and Otago regions. Despite this, the number of significant modern hard rock gold operations has been limited in recent years due to a lack of sustained exploration capital and not limited geological prospectivity.The New Zealand Government is actively encouraging explorers to invest in New Zealand through a series of targeted promotional visits, more importantly through the acquisition of precompetitive regional geophysical data. Data collection has been completed over the prospective Northland epithermal district and a large portion of the South IslandÆs west coast that is prospective for both orogenic gold and intrusive related gold.Analysis of new data has been an important component in aiding the generation of exploration targets from prospectivity modelling. Determining the prospectivity of an area involves reviewing all the available data and analysing it with respect to the most up-to-date mineral system model for the mineralisation style of interest. Using the weights of evidence modelling approach, the most prospective areas for epithermal gold-silver, orogenic gold and intrusion-related gold have been identified. The key exploration parameters relevant to each mineral system are first represented spatially and then statistically combined into a single prospectivity map. New potentially economic deposits could be found by focusing exploration on targets identified from these models. The prospectivity modelling approach can greatly reduce the risk involved in mineral exploration.CITATION:Peters, K and McKenzie, C, 2013. New Zealand gold potential - using mineral prospectivity modelling to evaluate gold-bearing mineral systems in an underexplored country, in Proceedings World Gold 2013 , pp 479-486 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By Robin J. Hickson

El Abra is one of the world’s premier copper de-posits. The project is located in northern Chile, 140 km (87 miles) inland from the Pacific coast. It has the same geologic age and structural setting as the world-class Chuquicamata copper mine located 42 km (26 miles) to the south. The current development plan for El Abra extracts798 Mt (879 million st) of high-quality oxide ore. This will require building a solvent extraction/electrowinning(SX/EW) facility that can produce 225 kt/a (248,000stpy) of cathode copper. This will make El Abra the largest SX/EW copper operation in the world, and the world’s seventh-largest copper producer.

Jan 1, 1996

By Arthur V. Corry

GOLD was discovered in Alder Gulch, Virginia. City, Mont., on May 26, 1863. In a short time some 6000 people flocked to the new discovery, and on the banks of Alder Gulch six settlements sprang into existence, the principal one, Virginia City, alone surviving. This town today has a population of 800, and is the county seat of Madison County. It is estimated that between forty and fifty million dollars in gold was produced up to 1904. Virginia City is situated at the mouth of Alder Creek where that stream leaves the narrow canyon that cuts the steep foothills flanking Old Baldy Mountain, elevation 9572 ft., 12 mi. south. Virginia City itself is 5700 ft. above sea level.

Jan 1, 1936

By R Wolff

One critical factor in open pit mining projects is the estimation of the recoverable reserves. The reason for this is that at the valuation stage there is a lack of information about future metal prices and production costs. Consequently, the estimation of the recoverable reserves needs to be done based on a fixed break-even cut-off grade (BECG), in which fixed expected metal prices and production costs are assumed throughout the operating life of the mine (OLM). In this paper, an alternative technique for estimating the recoverable reserves of an open pit mining project is presented and explained in detail. The main characteristic of this technique is that it estimates the recoverable reserves of the project using mining costs as reference: this is done due to the fact that mining costs are easier to model than metal prices. Another important characteristic of this technique is that it uses the uncertainty of the geology of the orebody, given by simulations of the deposit, to make final strategic decisions, such as the selection of the operating life of the mine and the optimal production rate, which minimise the risk of not achieving future production targets while maximising the upside potential of future rewards. As it will be shown, the final outcome of the proposed technique is the generation of a robust open pit design, that include cutbacks and ultimate pit limits, called the marginal open pit mine design (MOPMD). One characteristic of the MOPMD is that, at each production period, it will be characterised by their respective geological uncertainty, given as probability distributions of ore, waste and metal quantities, and by marginal economical project indicators, such as cut-off grades and metal prices, among others. The details follow in the paper.

Jan 1, 2006

By Isabella Cesario de Amaral Souza

A amostra de nefelina sienito cedida ao CETEM pela Nefelina Brasil Mineração está sendo estudada para utilização como fonte de potássio para a agricultura a partir da técnica de rochagem e de técnicas diretas de extração de potássio. Com esta finalidade, foi necessário avaliar as características físicas dessa rocha e a sua viabilidade na disponibilização do elemento de interesse. Para isto, um ensaio de liberação de potássio foi organizado, visando avaliar os parâmetros que mais influenciam nesta disponibilização como o tempo, a agitação/repouso e a proporção entre sólidos e líquidos. Foram testadas três soluções extratoras, a água deionizada e o hidróxido de sódio nas concentrações 1 e 3 mol.L-1. Conclui-se que o potencial da rocha como fonte de potássio é economicamente promissor.

Aug 16, 2017

By F. F. Aplan

For the past year, MBD has been engaged in a lively discussion on a name change for the Division. To complicate things, more than one name change has been proposed! There has been much discussion on the subject, as anyone who has attended the Annual MBD Business Meeting or read [jE] knows. The position of many of our members is well known. There is, however, one group that has not been heard from. These are the future members-the present students and those even younger who are yet to elect our profession. As one who has traversed the academic-industrial interface several times, I think I am qualified to speak for this group. Before going further I think it wise to state unequivocally that our Division should adequately represent our profession. The whole profession is just too small to chop into a plethora of pieces: "I'm not a mineral processing engineer, I'm an ore dresser-well, actually, I specialize in comminution, specifically in grinding, mostly in autogeneous grinding-primary autogeneous grinding that is-and my 'thing' is really iron ores, taconites, mind you!" Enough to confuse even those that keep the faith, and certainly we can't build a profession on such narrow pieces. Either an employer can hire a professional who knows the entire profession or he can't. As more and more companies search out opportunities in the mining and metallurgical fields and as environmental considerations bring into question even our technically well proven processes and procedures, there is a greater need than ever be- fore for a well-rounded mineral processing engineer well versed in all of the process possibilities. What is needed is one who can take an ore-or municipal trash for that matter-and produce there from a valuable product by the most appropriate means. It doesn't really matter if this is done physically, chemically or thermally.

Jan 1, 1971

By E. J. Gleim

This report describes a trip to Europe in the interest of safety in coal mines. It reviews the Eighth International Conference of Directors of Safety in Mines Re-search, which met in Dortmund-Derne, Germany, July 5-10, 1954, to discuss results of studies made in different countries to improve health and safety conditions under-ground. It also summarizes information on subjects of special interest in the United States gained by the writer in visits to mining experiment stations in Belgium, France, and England. The efforts being made to protect life and property underground were discussed, and ideas and experiences were interchanged freely, not only during the conference but also during visits to the several countries. Helpful information was obtained on many topics of interest, but time did not permit as thorough a discussion on some of them as might be desired.

Jan 1, 1956

By Francesco Chiappalone, Filippo Azzarà, Raffaele Aliberti, Daniele Nebbia, Lance Waddell

As part of the 3RPORT and NEBT Projects, 5-mile Combined Sewer Overflow Tunnels were excavated with a 19 ft diameter Slurry and 26 ft diameter EPB Tunnel Boring Machines. Due to the difficult geological and hydrogeological conditions, both tunnels were excavated maintaining a ground support pressure between 2 and 5.5 bar imposing significant challenges to the projects. The first part of the paper describes the general characteristics of both projects while the second part focuses on the challenges and technical details of the pressurized breakthroughs that took place in deep shafts excavated in urban environment as part of the projects.

Dec 1, 2022

By AIME AIME

INDUSTRIAL Pittsburgh, the center of the coal and iron and steel industry of the world, was host to the Coal Division at its Fall Meeting held there on Oct. 21 and 22 at the William Penn Hotel. The past year has witnessed remarkable progress in new methods of mining and burning of coal and many of the papers on the program discussed these developments. Nearly 100 had registered at the time of the first session on Wednesday morning and this number increased to 168 on Thursday. Owing to the large number of papers on the program, eighteen in all, it was necessary to hold group meetings on Thursday morning, with a capacity attendance at each meeting. . Chairman McAuliffe was on hand early Wednesday morning to open the meeting. George Otis Smith, representing President Lovejoy, came over from Cleveland where he attended the meetings of the Institute of Metals Division. Secretary Parsons arrived later from Cleveland and spent the whole morning with the executive committee of the Division. Doctor Smith, Secretary Parsons, and J. T. Breunich were the official representatives from Institute headquarters.

Jan 1, 1936

By Oliver Bowles

Whiting or Paris white is a fine-grained preparation of calcium carbonate having a wide variety of uses. Until recent years it was prepared almost exclusively from certain north European chalks. With the curtailment of imports of European chalk during the World War of 1914-18, however, finely ground limestone, of domestic origin was used more extensively to satisfy the American demand.

Jan 1, 1942

By M. A. Schellhardt, E. J. Dewees, R. Vincent Smith

"INTRODUCTION Abnormal material requirements of the nation at war impose an intensive demand upon many irreplaceable natural resources. Natural-3as reserves) for example, are being subjected at the present time to extensive depletion by large-scale withdrawals of gas to supply unprecedented demands for fuel and raw materials for the synthesis of strategic products. Fluids produced from many so-called gas-condensate type reservoirs have become an important source of hydrocarbons vital to the war effort.Development of gas-condensate type reservoirs in Arkansas, Louisiana, and Texas in recent years created many problems not common to ordinary gas-producing operations. Early in the development of condensate-type gas fields, general practices were evolved and applied to insure efficient re¬covery of the hydrocarbons existing in the gas phase under initial reservoir pressures and temperatures, put often the practices were predicted mainlyregardingupon generalized theory regarding the behavior of the fluids and were not always the most efficient, because field and laboratory procedure for testing these hydrocarbons had not progressed as rapidly or as far as field development. Specific information regarding the composition and properties of fluids ultimately recoverable from many gas-condensate reservoirs, especially, is lacking."

Oct 1, 1944

By I Gray

While in some cases it is vitally important to measure the virgin stress in rock prior to tunnelling there are a number of cases where such stress measurement is really not required. The concept of having to have a number to put in a numerical model representing a continuum is often quite inappropriate. This paper discusses the cases when virgin stress measurement is required and the most appropriate means to measure it. The techniques discussed cover all of the overcoring systems, hydrofracture and borehole breakout measurements. It also covers the use of rock surface stress measurement, which is easy to perform and should be used to check for changing stress conditions. Unfortunately this technique has been ignored in recent times because engineers are addicted to numerical models requiring far field stresses rather than measuring the real values that exist where they matter – at the tunnel wall. A case is presented in which the measurement of surface stress in a tunnel boring machine tunnel enabled the far field stress to be determined in what must be the world’s largest overcore.CITATION:Gray, I, 2014. The measurement of rock stress for tunnelling, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 153–160 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014