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By K. Adham

For use in many existing and emerging applications, the purification of natural graphite is required to achieve +99.9% carbon content with minimum metallic impurities. Currently, the hydrofluoric acid process is used, which carries certain environmental and workplace health and safety impacts. While thermal purification of graphite at temperatures over 2500 °C is a known alternative, such high-temperature furnaces are expensive to build and operate. Using chlorine at lower temperatures to purify graphite is also known and patented, but is currently limited to treating solid synthetic graphite shapes in small-scale batch furnaces. Chlorine treatment of natural flake graphite resources can be used commercially, if certain drawbacks are addressed through process improvements that can be helped with the use of fluidized bed reactor technology.

By M Yahyaei, P Knights, M S. Kizil, J Qu

Digital Twins (DTs) are transforming business operations across many industries through their accurate representations of physical entities enabled by IoT technologies.

Sep 1, 2024

By B. Weyerman

U. S. Steel's Oak Grove Mine experienced several top hinge failures on their caving shields. It was determined that all the caving shields needed to be replaced with new caving shields before more thilures occurred. The cost and amount of time needed for several scenarios of caving shield change outs were compared. This paper discusses how Oak Grove Mine decided to and did change 126 caving shields in six specially designed jig stations underground during a longwall move using their own UMWA employees.

Jan 1, 2001

By Turner WG, Short RR

Obviously, the paramount advantages of contract mining have been recognised by mine developers throughout Australia, as evidenced by surface gold mining operations of significant output almost exclusively being performed under contract. These paramount advantages of using an experienced professionally managed contractor result from the mine developer being freed from financing the required relatively large capital expenditure at current relatively high interest rates or in a capital scarce stock market, and from the need to recruit and sustain a large operating work force in a competitive labour market.

Jan 1, 1990

By William E. Roscoe

"Non-producing mineral properties include those at various stages of exploration, properties at the pre-feasibility or feasibility stage, properties with currently uneconomic mineral resources, and past-producers. The market approach is applicable to all these types of non-producing mineral properties. Income approach methods such as discounted cash flow and option pricing are generally not applicable to properties at the exploration stage, but may be applicable to non-producing mineral properties with defined mineral reserves or mineral resources.The value of a non-producing mineral property depends on its perceived potential for the existence and discovery of an economic mineral deposit. The potential, in turn, depends on a number of factors which must be considered when choosing market comparables. These comparability factors include such items as geology, mineralization, stage of exploration and results, mineral resources, location and geography, and political jurisdiction. The date of the market comparables must be within a reasonable time period of the valuation date of the subject property. Although it is difficult to find good market comparables because of the unique nature of mineral properties and the small number of transactions, these difficulties are compensated for by analyzing a number of transactions on similar properties to develop a range of values for the subject property.For valuation purposes, market comparables can be expressed in terms of total property value, value per unit area (e.g., $ per hectare), or value per unit of metal contained in mineral resources (e.g., $ per ounce of gold, or $ per pound of copper). The market comparable value can be used to estimate the value of the subject property by using the total property value, unit area value or contained metal value."

Jan 1, 2003

IF you do not make the disc at the same time as the core and as part of it, it is necessary to make it by itself. This is done by spreading on a board or other flat surface a layer of clay as thick and wide as [88] the disc that you made at the feeding head of the first pattern of the gun. When it is dry, mark it exactly with compasses and then, cutting with a chisel or rasp, make it fit exactly into the empty space at the head. Likewise, make a hole just as wide as the thickness of the core exactly in the middle of this clay disc. When you have put the disc in its place in the mould and then pass the core through this hole, it passes exactly through the center of the mould in such a way that it meets the iron ring that you put at the foot of the mould for this purpose. As I said above, if' you do not make it as part of the core, it is necessary to proceed in the aforesaid way. But if' you wish to make it attached to the core (which I like better because it can be done more accurately) make a

Jan 1, 1942

By Chas. L. Emery

"The laws of rock mechanics apply equally well to all rock structures, and open pits are not exceptions. The concepts and some arguments about the emphasis to be placed on various aspects of open-pit design are discussed in this article.RocksROCK can be described as a granular material consisting of grains and glue. The grains may be fragments of other rocks or polycrystalline aggregates. The glue may be ferruginous, calcareous, argillaceous, siliceous or other material connecting the grains. In a crystal intergrowth, the outer layers of the crystals in contact with each other may be considered to act as a glue. Water may be a glue in clay or a grain in a crystal structure. Air and other fluids or gases are grains if they occupy spaces in a granular mass. Such grains are functional either chemically or mechanically or both."

Jan 1, 1966

The Pogo Mine, near Delta Junction, Alaska is a new 2500 STPD gold operation. The control system of the mine and milling operations are a hybrid of DCS (Distributed Control System) control and PLC (Programming Logic Controller) control. A DeltaV DCS system serves as the main control and operation platform while the PLCs operate a multitude of vendor specific packages. The communication backbone of the DCS system is a hybrid of star and ring fiber optic topology, which provides reliability and flexibility. The communication between the DCS and PLCs is typically facilitated by serial communication. This communication insures the integrity of the whole control system.

Jan 1, 2008

By J Fraser, M Scoble

Within the past decade, incidents of mining–community conflicts have grown dramatically and represent one aspect of a phenomenon known as social risk. Research published in 2014 indicates that a lack of social acceptance is now a leading and costly cause of delays for mining projects.The rise of social risk, complemented by the need to earn the trust of an increasing number of stakeholders so that mining projects can be developed effectively, is problematic for the industry. Conflicts are occurring in situations where companies are fully compliant with regulatory and legal requirements, despite initiatives by mining companies to earn social acceptance and despite the proliferation of tools to support corporate social responsibility. Intensifying the impact of social risk is the fact that it has increased during a time in the global mining sector when companies have had to grapple with declining commodity prices, increasing capital costs and debt levels and the challenges of mining lower-grade deposits.This paper will explore a hypothesis that in today’s interconnected society, social risk in the mining sector constitutes a legitimate business risk that must be managed strategically. The reality facing mining companies is that information, once considered confidential, now travels quickly on social networks and via a growing number of groups and individuals that have earned a legitimate right to be classified as stakeholders in projects that affect their communities. To be successful, it is suggested that companies will benefit from increasing internal collaboration and providing training to equip teams to mitigate social risk to mining projects and protect reputation capital. The paper is based upon PhD research being undertaken to assess the points of intersection between social risk and social responsibility during the construction stage of greenfield mining projects.CITATION:Fraser, J and Scoble, M, 2015. Mining–community conflicts – can the future mining sector transform social responsibility?, in Proceedings Third International Future Mining Conference, pp 159–168 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

A study of drilling data at various stages of development of an orebody show that the semi-variogram, used for calculating the accuracy of block estimates can be ill-defined if too few data are available. The consequencesin this case are to have blocks supposedly more accurately known than is possible at the early drilling stage; such a result being potentially dangerous. However, as the amount of data increases the recalculated, semi-variograms approach the underlying semi-variogram of the deposit and the calculations made using them become more reliable and robust.

Jan 1, 1977

By A. Miller, M. McNinch, R. Jacksha

Each year, hundreds of mine workers are involved in machinery-related accidents. Many of these accidents involve inadequate or improper use of lockout/tagout (LOTO) procedures. To mitigate the occurrence of these accidents, new safety methods are needed to monitor access to hazardous areas around operating machinery, improve documentation/monitoring of maintenance that requires shutdown of the machinery, and prevent unexpected startup or movement during machine maintenance activities. The U.S. National Institute for Occupational Safety and Health (NIOSH) is currently researching the application of Internet of Things (IoT) technologies to provide intelligent machine monitoring as part of a comprehensive LOTO program. This paper introduces NIOSH’s two-phase implementation of an IoT-based intelligent machine monitoring system.

By Chi-Ming Chang

Alloy powders are commonly used in the purification of zinc sulfate solutions for use in standard electrowinning practice. The primary goal of this research was to study the use of zinc-lead alloys for similar reactions in the galvanic stripping of impurities from organic solutions. The effects of various parameters on the electrochemical behavior of commercially produced zinc-lead alloy powders were determined. A qualitative evaluation and summary of the influence of the more pertinent parameters on iron removal from di-(2-ethylhexyl) phosphoric acid (D2EHPA) by galvanic stripping is given. Water concentration, oxygen content and reaction temperature were the principal factors affecting the reaction rate and process efficiency. Activation energies were also calculated and indicated that the reaction changes from chemical to diffusion control .with increasing temperature in the range of 35" to 45°C. The results showed that zinc-lead alloy gave faster reaction rates with less sensitivity to process variables than SHG zinc as a reducing agent for galvanic stripping. The role of lead could be as cathodic sites for the reaction which enhances the zinc dissolution or anodic half reaction. The morphology of the zinc-lead alloy surfaces, before and after the reactions, supports this assumption.

Jan 1, 1998

By R. V. Lundquist

This report describes results of tests on the desilication of solutions resulting from the leaching of lime-soda sinters. Desilication was accomplished by heating the solutions in an autoclave. A liquor relatively free of silica was obtained after 30 minutes of heating at 200 p.s.i.g. in the presence of lime. The addition of lime improved desilication, but the rate and efficiency of desilication was effected by the quality of lime used. The optimum quantity of lime for effective desilication was about 6 grams per liter. A lesser quantity gave poorer desilication, and a greater quantity increased the alumina loss without improving desilication. The alumina loss was approximately proportional to the lime added. A complex structure, called artificial noselite in this report, was the only silica bearing compound detected in the desilication precipitate. Other compounds present were Ca(OH)2 (calcium hydroxide), CaCO3 (calcium carbonate), and Ca [A1(OH)6]2 (hydrated tricalcium aluminate). Sodium carbonate in the leach liquor retarded the formation of the calcium aluminate; hence it decreased the alumina lost to the precipitate. The extraction of alumina from aluminum silicate materials by the limestone soda-sinter process has been investigated by the Bureau of Mines for many years. The process consists of the following major operations: Blending the aluminum silicate with limestone and soda ash in such proportions that dicalcium silicate and sodium aluminate are formed on sintering; leaching the sinter in a carbonated caustic solution to extract the soluble alumina; purifying the leach liquor by the precipitation of soluble silica (this precipitate is designated desilication precipitate in this paper); precipitating alumina trihydrate from the purified liquors by carbonating with carbon dioxide gas; and calcining the trihydrate to alumina. Commercial grades of

Jan 1, 1962

Production sharing and cost apportionment in joint ventures is commonplace in Australasia today and elsewhere. It is a recognised convention that, with the exception of a free carry situation, joint venture participants usually share the proceeds of the joint venture in direct proportion to their respective participating interest, after having first paid its respective cash calls, in advance, to cover the projectÆs ongoing operating and capital cost requirements.In surface mines, the parties simply pay their way and take their proceeds in this manner. In underground mines, the situation is no different, though treatment of capital, depreciation and tax may differ between the parties. A common feature in many cases is the creation of a joint venture entity to conduct the business. This entity then collects cash from the parties, banks it, employs the staff, runs the operation, provides reports and pays out the proceeds. This convention appears to be relatively simple in application. In practice, it has been known to be complicated in the situation where the participants take their product at the mine gate and undertake their own marketing and selling arrangements. A more complex situation presents itself where the joint venture tenement boundary with an unrelated third party straddles an economic deposit. In this scenario, both the joint venture parties and the third party may wish to mine the deposit, sharing some infrastructure and costs, yet taking their own product as it is produced. A case study outlining such a situation is presented in the paper, outlining firstly how the major cost categories were identified and treated for cost apportionment purposes. Secondly, a mechanism for the equitable apportionment of product is suggested. Finally, issues such as timing and cost reporting are dealt with, together with a checklist of points which should be considered when a similar situation might arise in the future.

Jan 1, 2002

By Sylvie Lévesque, Cory Hennessey, Daniel Amariei

"In the iron ore industry, fine particles recovery is an important concern in terms of process performance and production costs. Continuous efforts are thus devoted to increase the efficiency in handling these fines.The Reflux Classifier (RC) is a relatively new technology that is mainly used in the coal and industrial minerals industries. The operating principle of this system is based on three mechanisms: hindered settling, autogenous dense medium and lamella settling. A preliminary evaluation of the Reflux Classifier technology for the beneficiation of iron ore fines was formerly done at the pilot scale using a RCTM300 unit. The good results obtained, using iron ore fines from screened spiral stream, made this technology very attractive for the iron industry. However, the high capacity of the RCTM300 unit (1–3 t/h), makes it unsuitable for R&D purposes. Thus, a smaller unit, the RCTM100, was assessed to validate the performances obtained with the RCTM300.This paper summarizes the performances obtained with the RCTM100. The challenges of the scale-down related to the adaptability of this technology to the iron ore industry are also presented. The results are compared to the RCTM300 performances, as well as benchmarked against sink-float tests. The metallurgical results on feed and products issued after the test work with the RCTM100 unit are supported by mineralogical characterization using a Mineral Liberation Analyzer.INTRODUCTIONFine particles recovery by physical separation means is a historical concern (Holland-Batt, 1992; Peukert and Wadenpohl, 2001; Srivastavaa et al., 2001; Majumder et al., 2003). Attempts to improve fine particle recovery at the laboratory, pilot and industrial scales adopting different strategies with traditional equipment or assessing new promising devices such as the MGS (multi-gravity separator), the Kelsey jig, the Yang jig, etc. (Kim, 2002; Goudreau, 2008; Kerr, 2012) have yielded variable success."

Jan 1, 2016

By R. L. Lewis

A simple method for estimating the steady-state water quality of a pit lake is presented. The steady-state concentration of a conservative chemical constituent in a pit lake is shown to be a simple function of inflow rate, evaporation rate, and inflow concentration. An analytical method is presented for estimating the equilibrium ground water inflow rate for use in water quality predictions. The time required to reach chemical steady-state is estimated using an iterative mass balance model. Mine operators should find the methodology useful for planning and screening-level regulatory applications where conservative estimates of pit lake water quality are desirable.

Jan 1, 1998

By Fred C. Bond

It sometimes happens that old knowledge is forgotten, or half-forgotten, and its rediscovery is hailed as a great new advance in technology. Autogenous grinding affords such an example. The oldest-or apparently the oldest-commercial application of continuous autogenous grinding on a large scale outside of South Africa occurred at San Juancito, Honduras, where a total of more than two million tons of silver ore were ground autogenously with complete success from 1918 to the early 1940's. The history of the San Juancito silver deposits begins in 1880 when- the New York and Honduras Rosario Mining Co. started mining silver at a rate which soon reached two million ounces of silver annually. In 1912 the Company's first mill, located in the village of San Juancito, was shut down and its equipment transferred to a new cyanide plant. This plant, constructed on a mountainside near the mine, was equipped with tube pebble mills in which Normandy or Danish pebbles were used initially.

Jan 5, 1963

By D. A. Meyer

The long and arduous process of bringing aggregate produced in Mexico to the Gulf Coast of the United States really began in the 1970s when the first exploratory trips were taken by Vulcan's geologists. It was not until the middle of the 1980s that all of the elements of the project seemed favorable and the largest capital investment in Vulcan's history was given the green light. The history of the project will be covered along with a discussion of the role that market forecasting played in the process. Is this the first of many or a once in a lifetime project? In July 1987, Vulcan and its joint venture partner broke ground in Mexico for a world-class limestone quarry and crushed stone production facility. This project is the largest ever undertaken by Vulcan's Construction Materials Group, with a total cost of over 200 million dollars -a cost shared equally by Vulcan and its joint venture partner, Ingenieros Civiles Associados, or ICA, a diversified Mexican company which is also the largest construction firm in Latin America.

Jan 1, 1995

"A simple approach to optimizing the performance of an operating carbon in pulp (CIP) or carbon in leach (CIL) plant is presented. It is possible to reproduce the performance of an operating CIP or CIL plant in the laboratory, in small scale batch tests in which the rates of gold leaching and carbon adsorption are determined, coupled with mathematical models that translate the batch kinetic data into predicted steady state profiles of gold in solution and on the carbon across multi-stage adsorption circuits.Once the performance of the commercial plant has been mimicked by the model, the plant operating parameters can be varied systematically in the model, and the likely response of the plant to the stepwise change can be determined. In this way it is possible to inexpensively optimize the design of both greenfields CIP or CIL circuits and plant expansions, or optimize the operating parameters of an existing plant, with no disruption to plant operations and no economic risk to the mining company.This approach has been adopted by IAMGOLD Corporation, to the immediate benefit of two of their existing gold operations. The methodology adopted and the results achieved are presented.INTRODUCTIONThe carbon in pulp (CIP) and carbon in leach (CIL) processes became firmly established in the gold mining industry in the 1980s, initially in South Africa and Australia, from where they spread rapidly to all the gold producing regions of the world. The percentage of annual global gold production by activated carbon-based processes grew from zero in the 1970s to almost 70% by the turn of the century, which represented a phenomenal rate of acceptance of a new technology by a traditionally conservative industry. The main reason for this rapid acceptance of the new technology was the fact that the first few large plants built in South Africa convincingly demonstrated better gold recoveries than the traditional filtration/Merrill Crowe process, with lower capital and operating costs. And as the plants developed an operating track record over their first few years of life, they proved to be remarkably robust mechanically, and highly tolerant of plant upsets, changes in feed composition and solution phase contaminants that had caused problems in Merrill Crowe plants."

Jan 1, 2011

By D. T. Couillard

Video technology is becoming an important tool for many designers of industrial training programs. This report describes how trainers at the Minntac Mine, Mt. Iron, MN, have developed videocassettes of safe job procedures (SJP's) for training miners assigned to perform unfamiliar work tasks. All steps necessary for videocassette production, from idea to finished product, as well as the required equipment and prices, are listed and/or briefly explained. Minntac officials believe that the SJP videocassettes have contributed significantly to a reduction in mine accidents.

Jan 1, 1985