Search Documents

By A. Feather

Avmin have developed a flowsheet for the refining of copper, nickel and cobalt from Nkomati concentrates. Cobalt is recovered from calcium-saturated solution using Cyanex® 272. Nickel is subsequently extracted using versatic acid. The loaded organic is stripped using spent electrolyte, producing advance electrolyte for recovery of nickel by electrowinning. Cobalt was recovered with >99.5% extraction efficiency, reducing cobalt from 1.8 g/l to <10 mg/l. The cobalt/nickel ratio in the cobalt product solution was >1500. Nickel solvent extraction was optimized to recover 99%, reducing the nickel concentration from 32 g/l to <0.3 g/l, while minimizing calcium deportment to the nickel electrowinning circuit.

Jan 1, 2002

By P. T. Slatter

The efficient and accurate design of pipe and pumping plant for non-Newtonian mineral slurries remains a problem. The objective of this paper is to present the development of the Balanced Beam Tube Viscometer (BBTV), an instrument which could facilitate more accurate design for these slurries. The background of rotational and tube viscometry is reviewed and the fundamental principles and inherent advantages of the BBTV are given. The design, data acquisition and processing techniques are introduced and results showing the reliability of the new instrument are presented and discussed. It is concluded that the BBTV is a reliable and versatile instrument for both routine analyses and research work, and has the potential to provide data for the refinement of the design procedure for mineral slurry pipe and plant design.

Jan 1, 1998

The commercial development of the shallow (2200 ft2 400 ft) Windalia sand reservoir at Barrow Island provided the opportunity to conduct an intensive drilling programme using equipment and techniques designed for optimum performance.During the initial exploratory and reservoir delineation phase, 12 specific Windalia test wells were drilled using drilling equipment with an optimum depth range of 6QOO ft - 8000 ft and a 9 5/8 in by 7 in. casing programme was employed. The average time from commencement of move-in to rig release exclusive of coring for five representative wells was 187 hr during this phase.Development drilling commenced December 1966 with one rig, with the second in operation January 1967.As of January 1 1968, 168 development wells had been completed. The two rigs employed are drive-in units equipped with a telescoping .gelf raising doubles mast.Optimum depth range with 4 1/2 in. drill pipe is 2500-4000 ft. Casing programme is 8 5/8 in. by 5 1/2 in. Efficient performance was achieved immediately. The average time from commencement of move-in to rig release for 15 wells drilled early in the development programme was 99 hr.By application of experience and further modification of techniques, performance was improved to an average time of 72 hr per well for 15 wells recently completed.The major drilling problem on Barrow Island is surface hole drilling due to the very hard surface limestone combined with complete loss of circulation at sea level.In this operation, significant improvements have been effected. During the exploratory phase drilling, 12 1/4 in hole to set 9 5/8 in. casing, average penetration rate was 23 ft/hr. At the commencement of the development programme penetration rate, drilling 10 5/8 in. hole to set 8 5/8 in. casing, was 28 ft/hr for the 15 early wells considered, improving to 55 ft/hr for the 15 recent wells considered.This programme is a team effort and much credit must be given to the enthusiastic co-operation of the two drilling contractors.The current field record is 2 days 4 hr with a 4 1/2 hr move including the drilling of mousehole and rathole.

Jan 1, 1968

Council for 1996/97 President Dr N.A. Barcza President Elect R.P. Mohring Vice Presidents Senior J.R. Dixon Junior M.H. Rogers Immediate Past President D.A.J. Ross-Watt Honorary Treasurer J.A. Cruise

Jan 1, 1997

By L. Nell

Bateman, like other engineering contractors, carries out or participates in many studies of potential projects in the Minerals Industry. This paper aims to explain the contracting approach to feasibility studies as practiced by Bateman, particularly where this differs from a traditional mining company approach. A brief description is provided of the usual phases of a project and the types of estimate needed to proceed from one phase to the next. Possible organizational structures involving different forms of association between owner, contractor and consultants are then outlined. The bulk of the paper then demonstrates that the cost estimates prepared stem directly from the mining plan, metallurgical process design and engineering design philosophy. The steps to be followed in order to prepare a credible estimate which accurately reflects the design constraints are described. The importance and the methodology of carrying out value engineering and of preparing contingency estimates based on a thorough risk analysis exercise are then discussed. Financial modelling techniques are described briefly. The paper concludes with short summary case studies of two recent investigations of potential projects in Africa.

Jan 1, 1999

By R. Banda

This paper describes the decision to implement and then the implementation itself, through trials, of electronic ?Smartdets? over previously used shock tubes. It concludes that Mufulira Mine has become the first mine in Zambia to convert 100% of its stoping to ?Smartdets?, because the Mine?s management was prepared to look beyond the unit cost of product and were ready to look at the broader picture of cost effectiveness and increased productivity.

Jan 1, 2005

By J. A. Flinn

Phelps Dodge’s Morenci copper mine has had six drills, six track-dozers, 16 shovels, two loaders, and 90 haul trucks equipped with either Caterpillar, Aquila, or Modular GPS systems for nearly three years. The Caterpillar Computer-Aided Earthmoving System is an open-architecture system, which allows for inputs to enhance orientation solutions and system functionality. This system has begun a new phase that leads to an intelligent mining system. Optimization techniques of the current system and inputs are reviewed. In addition, some practical issues of implementing new technology in a mining environment have been identified to aid in this new phase.

Jan 1, 2000

By J. C. Taylor

The Rhodax inertial cone grinder, designed by France?s FCB Group Fives, is the result of three years, theoretical and mechanical research in the field of compression grinding by the research staff of FCB?s CRM minerals research centre. A number of potential uses have been assessed and will be discussed in the paper. The crusher is an inertial grinder that works on the pressurized bed fragmentation principle. The fragmentation force is caused by the rotation of unbalanced masses rather than by an eccentric mass, as is the case in a conventional crusher. This makes it possible to achieve very high reduction ratios. By controlling the speed of rotation of the unbalanced masses, the grinding force can be modified, thus changing the product size distribution. The paper describes the machine layout, operating principles, control parameters and will briefly describe the results obtained on reef, waste and ROM reject pebbles. Some comparisons are made with conventional crushing.

Jan 1, 1998

By C N. Whata

While there is no specific obligation on the part of any applicant to consult directly with tangata whenua (people of the land), recent cases highlight the need to engage in active consultation in order to avoid serious objections and delay, particularly where a proposal may affect the matters referred to in section 6(e) (Waahi tapu/sacred places) and 7(a) (KaitiakitangaiGuardianship) of the RMA. &nbsp; The Environment Court has shown some sympathy for tangata whenua where waahi tapu and other significant matters of cultural concern are at risk because of a proposed development. There are several practical steps that can be taken to minimise the potential for serious objection including: ò knowing who to contact and how to contact them; ò demonstrating empathy for the concerns of tangata whenua; ò engaging in proactive consultation, for example meeting at a time and a place that is suitable to tangata whenua, and a preparedness to meet the costs of tangata whenua etc; ò demonstrate an awareness of tangata whenua issues; being aware of the types of mechanisms that are available to remedy, avoid etc adverse effects on matters of concern to tangata whenua.

Jan 1, 1997

By J. H. Potgieter

The method used to assess the reactivity of lime was evaluated to gauge it usefulness as a quality control tool. The effect of particle sizes, different lime and water masses for a fixed s:l ratio and the same for various s:l ratios on the reactivity values obtained, were investigated. An attempt to introduce the amount of grit produced during the slaking reaction as an additional measure of limeís quality and reactivity, proved to be unsuccessful. It was also found that the relative amount of lime slaked during the different tests was independent of the reactivity value of the lime. The investigation confirmed the usefulness of the accepted test procedure as are liable method to measure the reactivity of lime, despite various reservations expressed from a theoretical point of view.

Jan 1, 2002

By M. Fustic, A. H. Paul

The geology of the Muskeg River Oil Sands Mine is described to demonstrate how geologic modeling aided in resource evaluation and material characterization during the feasibility and construction stages. Bitumen is hosted in the clastic sediments of the Cretaceous McMurray Formation which is informally divided into members representing the fluvial, estuarine and marine environments of this transgressive sequence. Lithofacies mapping of drill core provides further detail to classify materials as resource type, for extraction suitability and for construction suitability. Geologic interpretation provides tools for the engineers to produce effective mine plans and for the operators to execute them during mine development.

Jan 1, 2002

By G. A. Kosick, G. S. Dobby

"This paper presents the principles and application of a recently developed control system for flotation columns and column circuits. The control system uses triple pressure sensors to directly sense zone densities and level, and to help in characterizing the operating behaviour of individual columns. A complete expert system development tool is incorporated within the system to provide the facility for full operator training, an on-line help facility, and a means for incorporating the column behavioural patterns into decision making rules. The system is configurable to any number of columns and can be run in either supervisory mode or direct control through Minnovex PIO software. Additional process signals can be interfaced with the system if desired. Operating experience with the control system on the Minnovex column flotation pilot plant is described.I: INTRODUCTIONColumn flotation cells have been more difficult to control and are more sensitive to circuit changes than conventional mechanical flotation cells. This susceptibility encouraged investigation into various types of control strategies ranging from inexpensive single pressure measurements for level control, to highly instrumented and expensive systems using a variety of control methods.Flotation operators, in many cases, do not understand the column control philosophy or have not been trained to deal with this new type of cell. Some operators have subsequently absolved themselves of the column operating responsibility. Some column cells, for example, have run for hours with slurry pouring over the top or no froth coming off at all.ColumnEX is a column flotation control system which was developed from the viewpoint of an operating shift foreman who wishes to:1. control the column or column circuit through a genuine understanding of what is happening inside the columns, and2. to share this knowledge with his flotation operators and be available to guide them through times of circuit upsets."

Jan 1, 1990

By J. Donovan Jacobs

Many improvements in the art of underground excavation have appeared during the past two decades. These improvements have been both in methods and in machinery and have resulted in more economical construction of today&apos;s tunnels. In the realm of machines, the developments of continuous boring heads for either soft ground or rock, random arm excavators and the sliding tunnel floor (Magic Carpet) have each made contributions toward more rapid tunneling. CONTINUITY OF ADVANCE Tunnel boring machines are often referred to as "continuous excavators". Continuous advance (without cyclical interruptions) has not been achieved, however, in any of the machines now in use. In most rotary-head tunnelers the thrust needed to make the cutters bite into the face is obtained from hydraulic cylinders reacting against anchoring devices held stationary by pads which grip against the sides of the tunnel. With this system the forward motion of the cutting head is continuous only until the propelling cylinders have reached their limit of extension. At this point the grippers must be released, moved forward and reset before a new cycle of advance can be begun. Some machines are built to obtain their propelling thrust from hydraulic cylinders pushing backward against newly-installed rings of tunnel support. This is the customary method for propulsion of shields. With it, each cyclical advance or "shove" must await the erection of a new ring of supports. Faster tunnel driving

Jan 1, 1974

This report describes the activities and publications of the Bureau of Mines Health and Safety Research and Testing Center, Pittsburgh, Pa., for the fiscal years 1960-65. It includes a discussion or work being conducted on roof control, dust explosions, ventilation, health, coal mine fire control, and electrical-mechanical testing, and an abstract of each paper published during the report period.

Jan 1, 1966

By J. P. Walsted

Offgrade chromite concentrate, with a Cr-Fe ratio of 1.3 to 1.4 has been successfully smelted to produce useful ferroalloys. The Cr-Fe ratio is not improved, but the alloys can be used without a too drastic change in normal steel-mill practice. The ordinary high-carbon ferrochrome has been successfully produced by smelting under highly acid smelting conditions. An alloy containing 50 percent chromium was produced at a power consumption of 4,490 kw.-hr. per ton of alloy. Alloys containing 20 percent silicon were made by direct smelting chromite concentrate and silica.

Jan 1, 1956

By Joseph A. DeCarlo

THE TOTAL VALUE of sales of coal-chemical materials in the 10-year period 1948-57 increased 34 percent or at an average annual rate of approximately 3.5 percent. According to the Chemical Industry Facts Book, third edition, 1957, published by Manufacturing Chemists&apos; Association, Inc., the production of industrial chemicals since 1939 "has grown at au average rate of about 10 percent" a year (p. 7). The rapid growth of the chemical industry increased requirements of chemical raw materials at a faster pace than could be supplied by coal carboniza¬tion, and view sources of supply became necessary. The petroleum industry in the past decade increased tremendously the flow of chemical raw materials to the chemical industry through the processing of crude petroleum and natural gas. Whereas coal carbonization supplied most of the raw materials for manufacturing synthetic organic chemicals before World War 11, coke ovens supplied only about 40 percent of the total used in 1957. Although the proportion of chemical raw materials supplied to the chemical industry by coke-oven operators declined, this source of supply is large and important to our economy. In 1957, the value of coal-chemical materials sold, including surplus gas used by producing companies, totaled $358 million, compared with $267 million in 1948. Major factors that contributed to this gain were (1) increased production of all coal chemicals and (2) higher prices for tax and light-oil products. Gains in output of coal chemicals resulted principally from expansion in carbonizing capacity of coke plants owned and operated by the iron and steel industry, as yields of the basic coal¬-chemical materials (tar, ammonia, light oil, and gas) varied only slightly during the 10 years under review.

Jan 1, 1959

By Frank G. Snyder, Paul E. Gerdemann

The Southeast Missouri lead district, located about 70 miles south of St. Louis, embraces four important sub-districts and several minor ones. The important sub-districts, in order of discovery, are Mine La Motte, the Old Lead Belt, Indian Creek, and the Viburnum Lead Belt. Descriptions that follow are of geology and ore deposits of the Old Lead Belt. The ore deposits are stratiform in character and are localized in a narrow carbonate bar and algal reef environment on the flanks of exposed Precambrian of the St. Francois Mountains. Ore structures include a variety of primary depositional features such as pinchout zones, disconformities, ridge structures, reefs, and submarine gravity slides. Faulting, prior to and during ore deposition, "prepared" the host rock and strongly fractured areas are mineralized much more intensively and extensively than unfractured parts of the same sedimentary structures. The deposits are epigenetic in character. Mineralization is believed to have occurred at the time that post-lower Ordovician faulting took place. The mineralizing solutions are believed to be concentrated brines from adjacent basins that moved out of the basins during faulting, uplift, and erosion of the St. Francois positive area.

Jan 1, 1968

By Usiminas -. Ipatinga e Cubatão

Objetivo: Apresentar o Balan&ccedil;o Energ&eacute;tico Global da Usiminas em 2013 - Usinas de Ipatinga e Cubat&atilde;o, com os principais indicadores de consumo das &aacute;reas produtoras. Al&eacute;m dos indicadores energ&eacute;ticos globais, o balan&ccedil;o apresenta os consumos f&iacute;sicos espec&iacute;ficos de cada insumo nas diversas &aacute;reas, permitindo a an&aacute;lise de cada setor das Usinas, isoladamente. Metodologia: Foram elaborados gr&aacute;ficos com indicadores de consumo energ&eacute;tico por um per&iacute;odo de cinco anos, bem como a distribui&ccedil;&atilde;o percentual nas &aacute;reas produtoras. Nestes gr&aacute;ficos, &eacute; evidenciada a evolu&ccedil;&atilde;o dos indicadores ao longo dos anos. &Eacute; tamb&eacute;m apresentada justificativa para a varia&ccedil;&atilde;o do indicador em rela&ccedil;&atilde;o ao ano anterior. Resultados: O trabalho apresenta an&aacute;lise das Usinas de Ipatinga e Cubat&atilde;o em rela&ccedil;&atilde;o &agrave; evolu&ccedil;&atilde;o do consumo energ&eacute;tico e sua distribui&ccedil;&atilde;o percentual nas &aacute;reas produtoras.

Jul 31, 2018

By Howard P. Hamlin, John W. Sweeney

Shales , clays , and loess in Iowa were tested and evaluated to determine feasibility of producing lightweight aggregate by commercial rotary - kiln or sintering methods . Preliminary testing was conducted in a muffle furnace . Rotary - kiln tests were conducted in a 16 - inch by 14 - foot rotary kiln . Concrete cylinders and cubes were tested to determine qualities of the aggregate . Three samples made suitable lightweight aggregate by rotary - kiln methods and two by sintering .

Jan 1, 1964

By Michael Samis

The real option valuation method is often presented as an alternative to the conventional discounted cash flow (DCF) approach because it is able to recognize additional project value due to the presence of management flexibility. However, these two valuation methods can be separated on a more fundamental level by their differences in risk discounting. Real option valuation applies the risk-adjustment to the source of uncertainty in the cash flow while the DCF method adjusts for risk at the aggregate level of net cash flow. This seemingly small difference is the reason why the real option method is able to differentiate between projects according to each project?s unique risk characteristics while the conventional DCF approach cannot. This paper provides an overview of the real options and DCF valuation frameworks and discusses the differences in risk discounting that exist between the two methods. Using grade-school mathematics, this paper clearly demonstrates how, with real options, a unique project risk discount can be calculated which is directly linked to the project?s unique risk profile. It also highlights why the DCF method fails in this regard and shows why a call to ?increase the Risk-Adjusted Discount Rate? is an incomplete solution at best. Finally, a heap-leach project and satellite reserve development project are valued with both techniques and the difference in investment conclusions is explained in terms of the risk-discounting concepts discussed here.

May 1, 2003