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By Marcello Crispi, Valdir Silva, Juarez Moraes

Companhia Vale do Rio Dote - CVRD is the largest mining company in Brazil and the largest iron ore producer in the world. Serra Geral Mine (SGM) is located at Iron Quadrangle of the State of Minas Gerais, approximately 80 kilometers from Belo Horizonte. Hematite and Itabirite are the two main minerals. A blasting with a spherical charge has been introduced at Serra Geral Mine, an iron ore producer in Brazil, belongs to the CVRD (51%) Kawasaki Steel Corporation (24.5%) others (24.5%), in order to improve fragmentation, as well, load, transportation and crushing productivity. This paper will present the results of a successful blast design with a spherical charge carried out by Serra Geral Mine, the Department of Mining Engineering at Escola de Minas - Federal University of Ouro Preto-UFOP associated to a Blasting Engineering Consultant. The results obtained in the field tests and how it was possible to increase the blast pattern in 53%, which allowed one reduction around 31% in the cost of blasting operation in the Serra Geral Mine, will be discussed in details.

Jan 1, 2002

By Keith L. Harris

The performance of the world economy improved significantly in 1984. Real world output!/ grew 4.3% (compared with 2.6% in 19831, the highest since the 4.4% increase recorded in 1978 (table 1). The output of industrial nations rose 4.9%, while that of the developing nations rose 3.7%. The United States and Japan had the largest increases in output of the major industrial nations, with respective increases of 6.8% and 5.8% (table 2). The components of real output with the most significant growth in the industrial countries were gross fixed investment (9.2%), consumer expenditure (3.1%), and public consumption (2.5%) (table 1). Industrial output, as measured by industrial production indices, has returned to about the 1980 level for most of the major industrial nations (table 2). Exceptions to this were industrial production in Japan and the United States; Japan's industrial production rose steadily throughout the 5-yr period and is now more than 16% above the 1980 level, and the industrial production index for the United States reached 11 1.2 (1980=100.0). Real total domestic demand grew at 8.7% in the United States, more than double the rate of Japan, which, at 4.0%, had the second-largest growth. Average demand for all industrial countries was up 5.1%. During 1984 the U.S. dollar showed great strength on international markets, contributing to large current-dollar negative net exports of goods and services and even larger negative net exports of the merchandise sector. While growing U.S. imports helped spread the benefits of the recovery, they also led to a widening of current account imbalances and growing trade tensions throughout the world.3/, 4/

Jan 1, 1985

By W. L. Dumoulin

A RATHER detailed description of the entire plant and leaching process was given in a paper recently presented to the Institute,1 so this paper will cover briefly only the crushing practice of the New Cornelia Copper Co. for the year, 1918. The ore, which is mined by steam shovels and loaded in side-dump cars, passes through two crushing plants. These crushing plants were constructed to crush the ore required by a leaching plant of 5000 tons daily, capacity, during a crushing period of 16 hours. The primary plant reduces to less than 3 in. (76 mm.) and the secondary plant, to ¼ in. (6.35 mm.), which is sufficiently fine for satisfactory percolation of solution through the ore in the leaching tanks, and to give good extraction. The ore is then conveyed to the leaching tanks by a system of 28-in.. (71-cm.) belt conveyors. On the way to the leaching tanks, it passes through an automatic sampling plant, where a 1-per cent. sample is taken. From the primary crushing plant, the ore is conveyed by two 36-in. (91-cm.) belt conveyors to a 10,000-ton steel storage bin, with a reinforced-concrete flat bottom. The ore discharges from the bottom of this bin onto four 20-in. belt conveyors, which deliver it to the four units of crushers in the secondary crushing plant. There is no storage bin between the mine and the primary crushing plant. The ore breaks very coarse, is very hard, and contains a great many boulders, some as large as 4 ½ by 4 1/2 by 10 ft. (1.3 by 1.3 by 3 m.). Jams form in the bowl of the coarse crusher in the primary crushing plant, as a consequence, and are freed by means of an immense steel hook operated from a 40-ton electric traveling crane.

Jan 8, 1919

By Anthony Leddin, Gillian Dooley

This paper is concerned with mineral policy in Ireland and how it might be improved to encourage more exploration and investment in mining in the country. The approach is to first outline the main desirable characteristics of a comprehensive national mineral policy document. This aspirational document is then used to assess the current regulatory, legislative and fiscal frameworks for mining in Ireland. The analysis also contains a brief account of the history, structure and characteristics of the mining industry in Ireland. The main focus of the paper is to identify those aspects of the existing framework that erode Ireland’s attractiveness to mineral investment and to suggest policy improvements.

Jan 1, 2005

By J. L. Carr

Every year, severe injuries and fatalities occur when a miner is struck or pinned by a continuous mining machine, shuttle car, scoop or other piece of mobile mining equipment. Proximity detection systems offer a means to prevent these types of injuries and fatalities by sensing the presence of a miner and disabling machine motion. Although hundreds of these systems are installed and in use in operating coal mines, the influence that coal has on the electromagnetic fields associated with these systems has never been rigorously quantified. NIOSH researchers have conducted tests to measure whether the proximity of coal has a significant influence on a popular design of proximity detection system. The system tested utilizes a low frequency magnetic field generator that would be mounted on the mining machine. At the NIOSH Safety Research Coal Mine in Pittsburgh, researchers measured the performance of a simplified proximity detection system of this type first on the surface then underground at varying distances from a coal face. Analysis of these measurements shows that the presence of coal does not have a measurable impact. Disclaimer: The findings and conclusions in this report are those of the author(s) and do not necessarily represent the views of the National Institute for Occupational Safety and Health. Reference to specific brand names does not imply endorsement by the National Institute for Occupational Safety and Health.

Feb 27, 2013

Jan 1, 1944

Jan 1, 1944

By W. F. Riggs

1 Flotation Analogy To explain flotation in simpler terms the following analogy will be used. A factory (the flotation cell) manufactures a product (collector coated mineral). The product (collector coated mineral) is transported to market (the launder). A truck (the frother) is used to transport the product (collector coated mineral) to the market (the launder). The truck (the frother) transports the product over a road (the froth bed). The truck (the frother) and product (collector coated mineral) are supported by tires (the air). 2 Assumptions This operating philosophy assumes that the correct collector dosage is present along with the correct particle size distribution, pH conditions, etc. and that the minimum required frother dosage is correct. 3 Collector Addition The collector addition as used at a flotation plant is based on dosage rate as determined by the amount of mineral value entering the concentrator. Collector is normally added at two points in the concentrator: The primary flotation circuit and staged addition in the rougher scavenger circuit. Surveys have shown that the staged collector addition provides an increase in the kinetics and increases the recovery of the valued mineral in the rougher scavenger circuit. 4 Frother 4.1 Frother Dosage As explained in the above analogy, frother can be likened to the truck that transports the product (collector coated mineral) to market (the launder). Just as you would not use a truck rated at 15 tonnes to transport a 20 tonne load, you cannot expect to transport coarse minerals to the launder when there is insufficient frother present. Frother dosage must always be at, or above the minimum target. If less frother than the required minimum is used, then coarse mineral particles will not be supported and transported to launder where the mineral is recovered. To the naked eye the froth characteristics, even when insufficient frother is used, will appear to be correct. You cannot see the coarse particles that are not being recovered in the froth. (See Section 4.2 below for an explanation of why this occurs.)

Jan 1, 2006

By A. L. Mular, R. P. Edwards

"The operation of flotation circuits is often regarded as a combination of art and science. Expert systems offer a method by which the art may be captured and supervisory control of flotation circuits fully realized. Operating knowledge, the art, can be consistently employed to enhance regulatory control through the judicious application of an expert system. Using an expert system, a supervisory control routine was developed, and successfully implemented, in the copper flotation circuit at Brenda Mines Ltd.The expert system ran in conjunction with regulatory PI controllers on a personal computer. The expert system received assays via an on-stream analyzer and adjusted regulatory loop setpoints as required in real-time. From its commissioning in November 1989, to the end of the mine's operation in June, 1990, the ES was enthusiastically embraced by the operators and attained operating levels superior to those achievable manually.INTRODUCTIONExpert system (ES) software springs from research into artificial intelligence and is currently making significant inroads into business and industry. Proponents of ES's make many attractive claims; they are a means of capturing the knowledge of experts and they can be programmed by non-programmers. To date, most uses of this software in the process industry are in off-line applications, meaning that the applications are not tied directly to operating (on-line) environments. Moreover, in on-line environments, they are typically employed as advisors and only suggest changes. Human operators are required to close-the-loop to the process. Yet, ES's should be applicable to operating environments and, if the claims of the proponents are valid, should also be better than existing tools. As an intelligent controller an ES must use the knowledge of experienced operators, apply it directly to a process and do this without the intervention of human operators. On-line applications have been successfully employed in the closed loop control of SAG circuits (Herbst et al., 1989) and flotation circuits (Hales, 1989). Harris and Kosick (1988) detail an implementation for flotation control at the Polaris Mine."

Jan 1, 1991

By Jeffrey Mitsopoulos

King County?s (KC) Brightwater Conveyance Project in Seattle, Washington involves the construction of approximately 21 kilometers (13 miles) of bored tunnel, in three contracts, with four TBM?s which produce large amounts of real-time digital mining data. To facilitate the management of TBM data with a single interface and assist in project Quality Assurance, KC?s Construction Manager (Jacobs Engineering) recommended the use of the software TPC (Tunneling Process Control), developed by Babendererde Engineers GmbH. The paper demonstrates how TPC was used for oversight, analysis and QA on a complex tunneling project and how contemporaneous review and management of data results in a better understanding of TBM performance than can be obtained by retrospective analysis of data.

This report is in fulfillment of Contract H0230031 awarded to Bituminous Coal Research, Inc., on May 23, 1973. The scope of work to be performed under this contract was divided into four phases: Phase I - Design, Phase II - Construction, Phase III - Field Demonstration, and Phase IV - Analysis and Final Report. During Phase I, an agreement was finalized with the Rochester and Pittsburgh Coal Co. for conducting field tests of the proposed shearer spray systems on a longwall panel in the company's Jane Mine in Indiana County, Pa. A drum was then designed which could be used on the Eickhoff shearer, Model EW170-L, being used on this longwall and which would utilize the following spray systems: 1. One spray nozzle located in front of each cutter bit with the jet directed at the cutting surface. 2. One spray nozzle located in back of each cutter bit with the jet directed at the back of the bit. 3. Standard Eickhoff nozzles located in a header along the drum scrolls. 4. A fixed header mounted on the shearer directly behind the drum to simulate the spray system originally used on the Eickhoff shearer.

Jan 1, 1976

By Susumu Tsubota

Three types of reference gold catalysts, i.e., 3wt%Au/TiO2 (Au-Ti: Type A), and 0.3wt%Au/Fe2O3 on alumina beads (AUS: Type B), and 5wt%Au/Fe2O3 (Au-Fe: Type C), were produced in a test plant scale by Sud-Chemie Catalysts Japan, INC. under the licensing of AIST. To evaluate the validity of the preparation methods and conditions used for the reference samples, elemental analyses by ICP, particle size measurements by TEM, and catalytic activity measurements for the oxidation of CO and H2 over these catalysts were made. Gold catalysts can be prepared in a large scale of ca 400g for the Au-Ti and Au-Fe catalysts, 5 kg for the AUS catalyst with good reproducibility. It was confirmed that they were available for useful as the reference gold catalysts of World Gold Council.

Oct 1, 2003

By Neil A. Brown

The trona deposits near Green River, in southwestern Wyoming are world class in size and quality. They contain more than 25 times the reserves of the next largest trona deposit at Lake Magadi in Kenya. Based on present rates of production, the Green River reserve should last for more than 500 years. Since their discovery in 1938, the Union Pacific Corp. has been instrumental in the promotion, development and production of soda ash in Wyoming. Union Pacific spent several years drilling the deposits and trying to promote them to chemical companies. In 1947, Westvaco and Union Pacific entered into what became the first trona lease agreement. Today, the Green River Basin leads the world in soda ash production, accounting for about 25% of the world's supply. Green River producers process more than 14.5 Mt/a (16 million stpy) of trona to produce more than 8 Mt/a (9 million stpy) of soda ash. The future for Green River soda ash looks good, with more of the world looking towards the cheaper and higher quality source of soda ash coming from the natural deposits. Production from the Green River deposits should continue to grow as trade barriers and tariffs begin to fall in Europe and energy and environmental costs force the synthetic producers to exit the market.

Jan 1, 1995

By Jerry A. Wichser

A series of linear programmed instruction modules was developed in the general subject areas of Blasting Technology & Explosives Safety & Electrical Training. The linear programs (modules) were developed in the form of tape-slide plus workbook materials, while the branching format evolved from the LTS teaching machine system from MIT, through several other teaching machines and micro-computers, finally settling on Radio Shack TRS-80 microcomputers, Models I & III. Initial validation figures indicate that essentially the same result, are attained from both methods (based on pre and post test scores), with the most noticeable difference being an approximately 25% savings in study time with the branching modules. In December 1980, the development of modules on High-Voltage Training, Trolley Wireman Training, and Compressed Gas Safety was added to the overall tasks of the contract.

Jan 1, 1984

By W. J. Witte, M. K. Witte

"The purpose of this report is to present a generalized preliminary design and cost estimates for a typical heap leach operation such as might be undertaken in Northern Ontario. This report should be of value to anyone in the mining industry planning, or contemplating, a heap leaching operation in Ontario, either on a large or small scale. While more detailed costing and design work will obviously be required for each specific project being contemplated, the data provided in this report should enable parties to make preliminary estimates of the costs of proposed projects and should identify most of the planning and design parameters that will need to be considered.Although heap leaching has been used extensively as a low cost gold recovery method in other parts of the world for many years, it has only recently become of interest to the Canadian mining industry.In order to investigate and demonstrate the feasibility of using heap leaching in Ontario, the Ontario Ministry of Natural Resources in 1982, undertook to locate a private sector proponent willing to undertake a 10,000 ton demonstration project. This project was to have been carried out at a production scale under normal northern Ontario field conditions. The Ministry was to have provided technical management and design for the designated project."

Jan 1, 1985

By K F. Tang, J-W Li

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Xiong’ershan district in the southern margin of the North China Craton (NCC) contains more than 20 gold deposits hosted in the late Neoarchean to early Palaeoproterozoic amphibolite facies metamorphic rocks or late Palaeoproterozoic unmetamorphosed volcanic rocks. Gold mineralisation consists mainly of auriferous quartz veins and disseminated ores in hydrothermally altered zones, with additional gold mineralised breccia pipes. Gold orebodies are strictly controlled by secondary- or higher-order brittle/ductile-brittle faults. Isotopic dating reveals two separate episodes of gold mineralisation: the Shanggong and Dianfang deposits formed in the range of 236 ± 1.4 to 202 ± 18 Ma, whereas the Gongyu, Qianhe and Qiyugou deposits formed between 135.0 ± 0.5 Ma and 124.0 ± 1.0 Ma. Stable isotope and noble gas geochemistry studies indicate that the Triassic gold deposits were precipitated from deeply-sourced, low-salinity fluids at 250–350°C, but whether the fluids were mainly derived from metamorphic devolatilisation or magmatic degassing remains unresolved. In contrast, the Early Cretaceous deposits most likely precipitated from a dominantly magmatic fluid, although metamorphic and meteoric components cannot be ruled out. Results from this study, when combined with regional geological and geochemical data, suggest that the Triassic gold mineralisation was generated by the deformation associated with the collision between the North China and Yangtze cratons, forming the Qinling-Dabie orogen. In contrast, the Early Cretaceous gold veining was a result of lithospheric destruction of the NCC, a process initiated by plate subduction from both the south and north since late Palaeozoic but ultimately triggered by the westward subduction of the palaeo-Pacific plate in the late Mesozoic. This study helps to reconcile the long-term debate on the timing, genesis and geodynamic setting of gold mineralisation in the Xiong’ershan and other districts along the southern margin of the NCC.CITATION:Li, J-W and Tang, K F, 2015. Gold deposits in the Xiong’ershan District, Southern North China Craton – products of Triassic deformation and Cretaceous craton destruction, in Proceedings PACRIM 2015 Congress, pp 341–344 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By G. Deschenes, W. Yen

Ammonium thiosulphate is a non-cyanide lixiviant for gold leaching. The major problem is the high reagent consumption. A combination of 0.3M (NH4)2S2O3, 0.03M CuSO4, 3M NH3 was used to leach a copper-bearing gold ore at pH 10.2 for 24 hours. 30 kg/t of thiosulphate was consumed. Oxygen and copper species were found to be responsible for thiosulphate decomposition. The thiosulphate consumption could be reduced to around 17 kg/t by adding chelating agent, reducing copper sulphate concentration to 0.001 M and replacing CuSO4 by NiSO4. The increase of pulp density might reduce the thiosulphate consumption to around 17 kg/t. By regulating the oxygen supply, the thiosulphate consumption could be reduced to 10 kg/t.

Jan 1, 2002

By Eric C. Halpin

"1. Introduction and Backgrounda. In its fundamental form, risk is simply the likelihood of an adverse impact. Expanding on this theme, the Corps of Engineers has broadly defined risk associated with infrastructure as a factor of three distinct elements: a probabilistic assessment of a hazard such as a flood or earthquake; a probabilistic assessment of how the infrastructure performs in the face of this hazard; and a measure of the likely consequences – loss of life, economic damage, environmental impacts – associated with the resulting inundation scenarios.b. The lessons and observations described herein relate to the Corps of Engineers experiences in implementing risk concepts for infrastructure management during the period 2005 through 2013. The Corps of Engineers is a large, decentrally operated and centrally led federal agency that plans, designs, constructs, operates, maintains, and/or manages a portfolio of over 3,000 built dam and levee systems within the United States. The infrastructure in this portfolio is 55 years old on average, and although much of the structures provide for flood risk management benefits, many of the dams deliver multi-purpose benefits. Scale matters – where scale and uncertainty are large, risk concepts provide great opportunity and arrangement for application.c. The amount of organizational change that is demanded for the implementation of risk concepts is considerable and should not be under estimated, but need not be feared if the path others have taken is considered. This paper is, in many ways, an opportunity to step back from the last seven years of implementing risk informed management, check our own azimuth and maturation, and share the purpose and energy behind our own continuing actions. Hopefully, this azimuth check is also beneficial to those that are either considering the use of risk or are in the process of implementing risk concepts.d. Success at managing the massive change related to incorporation of risk concepts will directly affect success of the infrastructure program. The three key organizational elements to consider –human systems such as governance and competencies; policies that outline the who, when, and why of decisions and management; and the processes and technology that outline how work is to be performed - are changed fundamentally. From senior leaders to project team members and all of the people in between, there is a need to discuss, confront, and vet the change and the role people and organizations have in the process. For the Corps of Engineers, with a history of over two centuries, deeply embedded beliefs about infrastructure aren’t transformed over night - the change process is decadal in scope. Given our self imposed “project execution” mantra and corporate objective, risk seemed threatening at first to the cost and schedule of delivering infrastructure projects. In reality, risk concepts have been responsible for savings and cost avoidance of nearly $6 billion over the last three years alone while at the same time justifying increased investment by several fold for the highest risk needs."

Jan 1, 2014

By Charles B. Carpenter

In general terminology, the West Texas Permian Basin companies the area south of the Texas Panhandle and west of the Bend Arch or Central Basin region. It is outlined more definitely by geologists however, as that area underlain by the south half of the Permian Salt Basin4/ and includes Scurry, Mitchell, Sterling, Howard, Glasscock, Reagan, Crockett, Upton, Midland, Martin, Gaines, Andrews, rotor, Crane, Pecos, Ward, Winkler, and Loving Counties in Texas, and.. Lea and Eddy Counties in New Mexico. The oil fields of the area, of which more than 70 have been discovered, are shown in fire 1. Approximately 4,200 producing oil wells have been drilled in these fields. Oil has been produced from limestones and dolomites of Permian age in most of the fields in the West Texas Permian Basin. Some of the fields produced oil from sandstone beds above the limestone, and in two fields production has been found below the limestone in formations of Ordovician age.

Jan 1, 1936

By Charles B. Carpenter

In general terminology, the West Texas Permian Basin comprises the area south of the Texas Panhandle and west of the Bend Arch or Central Basin region. It is outlined mere definitely by geologists, however, as that area underlain by the south half of the Permian Salt Basin4/ and includes Scurry, Mitchell, Sterling, Howard, Glasscock, Reagan, Crockett, Upton, Midland, Martin, Gaines, Andrews, Ector, Crane, Pecos, Ward, Winkler, and Loving Counties in Texas, and Lea and Eddy Counties in New Mexico. The oil fields of the area, of which more than 70 have been discovered, are shown in fire 1. Approximately 4,200 producing oil wells have been drilled in these fields. Oil has been produced from limestones and dolomites of Permian age in most of the fields in the West Texas Permian Basin. Some of the fields produced oil from sandstone beds above the limestone, and in two fields production has been found below the limestone in formations of Ordovician age.

Jan 1, 1936