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By S. W. Arambur

INTRODUCTION "Mujeres Roca" is a program developed by OMA in association with the Chamber of Commerce Canada Peru inspired in “Women who Rock”, a Canadian initiative to promote a greater participation of women in the mining industry. The program includes a coaching workshop called “Kallpa Warmi”, that means “Woman Strength”, to reinforce basic skills and values and 8 mentoring sessions with top executives of the mining industry who share their experiences and knowledge with a group of 10 selected young professional women from around the country. HISTORY OMA is a nonprofit association founded in 2014 dedicated to contributing to the education of low-income university students with high academic performance in careers related to mining and earth sciences. Our mission is to empower the future professionals by strengthening their soft skills and enhancing their capacity to become leaders and agents of change in their own regions. The Chamber of Commerce Canada Peru has a long-standing commitment to gender equality and promotes women participation in male dominated industries. As it is well known, the mining sector is and has always been key to Peru’s economy, representing about 10% of the country’s GDP. Thus, mining can contribute significantly to our economic development and we believe that women can make a positive difference. A study prepared by PwC and "Women in Mining” provided indicators on the advantages that mining companies have when including women in their executive’s positions. These indicators sustain that when a mining company includes women in its management staff, its net profit increases by 6%. This information clearly shows that women participation is not only a matter of human rights and gender equality, but of productivity and profitability. Nevertheless, the mining sector has the fewer number of women on boards of any industry group in the world. Having this in mind, OMA decided to expand its activities and create together with the Chamber of Commerce Canada Peru, the program “Mujeres Roca”, in order to inspire and attract young women to the mining sector, a traditionally masculine industry. The program also aims to encourage mining companies to more actively recruit and keep women in their boards. The program was launched in 2016 within the framework of EXPOMINA PERU, the largest international mining exhibition that take place in Lima every two years.

Jan 1, 2019

By M. Westendorf, T. Banerjee, S. Kaushik, D. Tinney

"Cyclones are one of the most extensively used pieces of equipment within the mineral processing industry because of their simplistic operating and maintenance philosophies. They are commonly used as classifiers within the comminution circuit to control the grinding product particle size for satisfactory performance of downstream operations.Cyclones are a key contributor to the effective operation of the plant and have a significant impact on the mineral processing plant operations. If the cyclones are not performing as they should, the results are often a combination of lost recovery, grade, capacity and reduced throughput. Similarly, an inefficient cyclone operation may also lead to low or high recirculating loads that impact the efficiency of the comminution circuit. This highlights the importance of having proper stability in cyclone operation while implementing any plant-wide optimization strategy.One of the key challenges in cyclone operation is that cyclones are highly sensitive to changes in operating conditions and are affected by process fluctuations such as feed pressure, solids concentration and flow rates. Fluctuations in cyclone feed characteristics lead to unstable cyclone performance which affects mineral liberation. For such an impactful unit operation, cyclones have historically been under-instrumented in an otherwise highly instrumented process plant. Traditionally, mill operators have relied on visual observations of the apex discharge to determine the operating state of the cyclones. Visual cues corresponding to the different cyclone operating conditions have been discussed by Neesse et al. (2004) as shown in Fig. 1."

Jan 1, 2014

By Robert Moore Lewis

A unit for separating minerals into two prescribed size fractions, designated as a Lewis Hydrosizer, was developed at the North Carolina State University Minerals Research Laboratory. Ore samples with different mineral compositions, including coal, were separated effectively with the laboratory continuous unit. Commercial size units are in operation in North Carolina and Mexico, and under construction in Norway. Additional units are being build or are in the planning stage at several companies.

Jan 1, 1983

By D. C. Hogeman

Growing Greener is the single largest investment of state funds in Pennsylvania’s history, allocated to address the Commonwealth’s critical environmental concerns. Signed into law by Governor Tom Ridge on December 15, 1999, Growing Greener will enable the Department of Environmental Protection (DEP) to appropriate nearly $240 million over five years, to watershed restoration and protection, abandoned mine reclamation, and oil and gas well plugging projects. DEP has utilized these allocations in some remarkably innovative ways, as it: involves the cooperation of several state agencies, local governments, and grassroots organizations to address environmental concerns of the Commonwealth, provides funds directly to watershed groups based on locally determined decisions for local watersheds and offers a user friendly process. In three years, over $130 million in watershed restoration and improvement projects have been initiated.

Jan 1, 2002

By J. C. Wynn

J.R. Hillebrand From the abstract, "A realistic ore deposition model to serve as a conceptual framework." Further, on page 246, "The first area of study was the Josephine peridotite, now identified as an ophiolite terrane, located in northern California and south-western Oregon (Fig. 3). Here, it was felt that we could test the models shown in Figs. 1 and 2 and, if successful, expand the model and test it in other chromite districts in the US and around the world." My comments refer only to chromite deposits in Europe and the Middle East. First, I question that may chromite deposits occur in the idealized ophiolite section shown in Fig. 1. Second, although some podiform deposits (referring to morphology) have been important (Guleman, Turkey, for example), the stratiform deposits are of greater importance in tonnage and frequently grade. Examples include Nada, Yugoslavia; Bulqiza, Albania; Xerolivado, Greece; Saranovsk, Russia; and Abdasht, Iran. Reply by J.C. Wynn Mr. Hillebrand raises two issues that deserve a serious response. One issue is basically subjective and the other is ultimately political. First, the question of where (and how many) podiform chromite deposits are found in the idealized ophiolite section of Dickey (1975). The Dickey model is still perhaps somewhat controversial (Panayoutou, 1980), but our experience in the Josephine ophiolite of northern California (Wynn, 1980; and Albers, 1983) shows that the model works well there. Virtually all the chromite is found in dunite lenses in the tectonite peridotite (harzburgite). Since there are few complete ophiolites exposed in the world, the model will probably never satisfy everyone. The degree of acceptance is a function of any individual's subjective experience. Second, it is well known that stratiform chromite contributes more than 95% of the chromite reserves presently known in the world, and it could be reasonably argued that there is no point in exploring for or exploiting podiform deposits further. The title of the paper, however, was in part 'strategic minerals geophysical research'; chromite is considered a strategic and critical mineral of the US and many other industrialized nations. Stratiform deposits in South Africa and Zimbabwe account for most of the chromite reserves in the world. Unfortunately, experience in modern times with substantial price fluctuations and even resource cartels dictates the wisdom of identifying and maintaining a national chromite reserve, irrespective of the cost. An improved exploration methodology is an essential element in this strategic objective. References Albers, J.P., 1983, "Geological and Geophysical Studies of Chromite Deposits in the Josephine peridotite, California and Oregon," US Geological Survey Bulletin 1546 A-D, 118 pp. Dickey, J.S. Jr., 1975, "A Hypothesis of Origin for Podiform Chromite Deposits," Geochimica et Cosmochimica Acta, Vol. 39, pp. 1061.1074. Panayiotou, 1980, Proceedings, International Ophiolite Symposium, Cyprus, 1979, 781 pp. Wynn, J.C., 1980, "Exploration Geophysical Methods and Strategies, and Their use to Locate and Assess Small Mineral Deposits," Chapter 12 of Meyer and Carmen, eds., The Future of Small Scale Mining, McGraw-Hill, New York, pp. 75-83.

Jan 12, 1983

By R. Owen

The vision-based approach to process control involving fine particles in harsh on-line environments is discussed in this paper. The sensor equipment at the process location, consisting of a light source and a CCD camera provides RS-170 B&W video output. The video can be seen on a process monitor in the control room and is sent to a computer based Vision Processor. The Vision Processor contains a video digitizer and Canty developed software that extracts process information. The iron mine application controls thickener agent feed rate and thus settling pond overflow clarity. The sensor is mounted in the overflow flume of the outdoor settling pond and is used year around in the Minnesota weather. Alternate control system needs a low flow water sample which is subject to freezing in winter. The computer based vision processor provides 4-20 mA analog outputs for real time control as well as file archive for a history record.

Jan 1, 2001

By Vladimir Admek, Paul W. Jeran, Michael A. Trevits

It has' been found that lithological conditions over the Pittsburgh Coal bed cause the subsidence coefficient to vary within the area of the subsidence trough. This precludes the use of European developed predictive models, which are based upon a constant subsidence coefficient. Regression analysis of the distribution of subsidence coefficients from 11 Bureau of Mines, U.S. Department of the Interior, longwall panel studies on the location relative to the edge of the panel has yielded a third degree polynomial equation. This equation has been incorporated into a BASIC computer program for use on a personal computer that allows users with no previous knowledge of the theory of subsidence to predict vertical movements over typical longwall panels in the Northern Appa1achian Coal Basin.

Jan 1, 1986

By R. A. Ynchausti

In January 1993, Pyramid Resources began implementation of a supervisory expert control system at a U.S Cu concentrator. The objective of this control system was to improve plant profitability through unit operation optimization and integration. This paper documents the key aspects of the project, including: economic and associated benefits, system architecture, concepts of implementation, process control strategies, practical aspects of implementation and conclusions. The implementation of expert control at this concentrator has resulted in an estimated benefit of $50,500 per day. This is a net result of improved tonnage, reduced reagent consumption, improved concentrate grade and reduced energy per ton produced.

Jan 1, 1995

By H. Sis, D. Dahlin, S. Chander, C. Summers

Bench-scale selective-flocculation tests were conducted on samples of Florida and Western phosphate process tailings. Physical, mineralogical, and surface characteristics were determined for both types of samples. The flocculation tests investigated dispersant and flocculant types and doses, pH, and slurry percent solids, while other parameters were held constant. Where selectivity was achieved, phosphate minerals remained dispersed, whereas silicate minerals flocculated and settled. In single-stage tests, flocculants having low to medium anionic character effectively upgraded products at moderately elevated pH. Multiple-stage tests, and tests in which flocculants of lower molecular weight were used as site-blockers, gave improved results.

Jan 1, 2002

By John T. Cantwell

INTRODUCTION The process engineer usually is responsible for the design operating philosophy and/or day-to-day operations of a process. Since instrumentation is an integral part of the operation, it is essential that engineers understand the general capabilities of the different types of control equipment available. Many "noncontrol" engineers have become involved with instrumentation for machinery monitoring and control as well as other plant applications. The advent of the microprocessor has led to significant changes in control, both in systems configurations and man-machine interfaces. Today's concept is called simply "distributed control." What is distributed control? Distributed control is exactly what the name implies; the control system is divided into several functional segments and spread out to cover a process. The systems are distributed for physical, functional, and risk reasons. Before delving further into the specifics of distributed control, let's look at the evolution of control systems to see how we got here. Instruments initially were located near measurement and control points in the field. Operators physically had to go to the instrument to change setpoints or take measurements. As processes became more complex, it became evident that a central control area was required. This allowed an operator to monitor and control many variables. The operator's effectiveness was increased dramatically, which resulted in greater efficiency, better quality control, and lower personnel requirements. At the same time, plants became much larger, control applications became more complex, energy became expensive, and the industry became more competitive. All of these factors placed pressure on process and production engineers to get the most for the money. The result was a continuing push to put more instrumentation into a central control room to maximize efficiency and productivity and minimize manpower. This chapter deals in some detail with devices for measuring physical and chemical properties of coal; devices for measuring the weight and weight-rate of flow of coal; devices for the monitoring and control of conveyor systems, solids inventory, fluid flow, liquid level, density, and specific gravity. These instruments have a multitude of uses throughout a coal preparation plant. The discussions cover advancements in "on-line analysis," nuclear control devices, and distributed control using microprocessors, mainframes, and soft-

Jan 1, 1991

By R. C. Emmett

The industrial practice of concentration of solids and production of clear solution by gravity sedimentation is an old technology. Through the years, many devices have been designed and built to aid this process. One of the more significant developments was a revolving rake mechanism to convey settled material to a central discharge point of a circular tank, patented in 1907(1). In recent years, clarification systems employing parallel inclined plates have appeared on the market; the original device utilizing this principle was patented in 1886(2). Numerous other methods have been invented, tested, discarded and sometimes re-invented, all with the specific intention of improving the capacity of a particular settling area. Sedimentation theory, as expressed in Stokes' Law, shows that the rate of settling of a particle is directly proportional to the difference in density between the particle and the surrounding liquid and, more significantly, proportional to the square of the particle diameter. Anything that can increase the latter will greatly assist sedimentation and, as a result, flocculation always has been an integral part of sedimentation. Most materials suspended in aqueous media are naturally flocculent to some degree and, hence, are readily concentrated by sedimentation, although sometimes very slowly.

Jan 1, 1978

By M. C. Fuerstenau

Collophane, cryptocrystalline fluor-apatite, is examined as a substrate for plant water and wastewater remediation. The attenuation of Fe3+, Fe2+, Hg2+, Pb2+, and Cd2+ is presented as a function of metal ion concentration, amount of collophane, initial pH and conditioning time. TCLP results for Pb2+contaminated collophane are presented. Mechanisms of adsorption for divalent and trivalent species are suggested.

Jan 1, 2001

By Sun Guangzhong, Liang Jinhuo

Adverse geological condition is a major factor which makes construction difficulty in tunneling. But if it is predicted and tunnel support is made efficiently in time, the above difficulty can be reduced. It is necessary to develop one or several effective and economical geological methods for prediction of tunnel geology while expensive and time-consuming instruments are used. This paper reviews and proposes several geological methods for prediction of fault, seam, contact zone, and groundwater inrush. These methods have been proved to be effective and economical in tunneling practice in China.

Jan 1, 1987

By Manfred Jaeger, Klaus Ertmer, Walter Dietrich, Jochen Greinacher, Wilhelm J. Kogelmann

In Europe, novel low-cost excavator-mounted Multi Tool Miner (MTM) systems, consisting of cutter head, hammer, bucket and drill attachments permit one unit to perform multiple tasks replacing several purpose-built machines. At the Weser Tunnel in Germany, cross-passages between the twin tubes were excavated in frozen ground with a remote-controlled mini-excavator equipped with a quick-change cutter head, ripper tooth and bucket. In Switzerland at the N2 interstate near Basel, W. Dietrich AG enlarged a 2-lane tunnel to three lanes with a cutter head mounted on a special excavator. Blasting and heavy hammers were not permitted due to the closeness of the “live” twin tube. At the N20 Zurich bypass, the Joint Venture of Jaeger, Frutingerand AHB excavates highway tunnels, some with extremely large cross sections, conventionally. A cutter head mounted on an excavator removes the rock shattered by blasting precisely to the pay line, thus preserving the rock’s self-supporting capacity preventing subsidence and damages to water resources and buildings on the surface under low overburden.

Jan 1, 2003

By James A. Curry

Table I identifies the maximum cost of the individual provisions with spoil disposal in Appalachia leading at $3.98 per ton, This was followed by deep mine subsidence control and monitoring at $1.66 per ton. At the request of the U.S. Department of Energy, the Bowser-Morner Testing Laboratories of Dayton, Ohio, evaluated Consol's cost estimates for 14 of the 21 regulatory provisions the company studied. It is interesting to note that Bowser-Morner concluded that Consol's estimates of costs were very conservative and that the actual costs will be substantially higher than what the company reported. In 1978 a joint committee of the National Coal Association and the American Mining Congress made estimates of cost impacts under 11 OSM permanent rules (see Table II). Six rules applied to mid-western strip mining were projected to cost $6.52 to $17.17 per ton. Five rules applied to mid-western strip mines showed costs ranging from $.91 to $6.11 per ton. Three rules applied to deep mines (regardless of region) were seen raising costs from $ .57 to $2.67 per ton. The joint committee reported trouble developing overall figures because member firms used widely different assumptions in calculating their costs. That same statement could no doubt be made when comparing most cost data available today.

Jan 1, 1980

By J. Baz-Dresch

A custom-designed shotcrete system, consisting of an 8-m3 (10-cu-yd) transit mixer and a shotcrete spray boon carrier, is used by a two-man crew to transport and place up to 25 m3 (32 cu-yd) of steel fiber reinforced, dry, silica fume shotcrete per 11-hour shift. Shotcrete is custom blended by a local supplier and delivered predampened. Mix design and quality control are performed with a computer program that develops and graphs a properly balanced mix based upon the materials sieve analyses.

Jan 1, 1992

By L. B. Phelps

The nation is confronted with thousands of acres of abandoned coal lands. In Pennsylvania alone, these lands have been estimated to cost $15 billion to reclaim (Pennsylvania Bulletin, 1985). One way to deal with this problem is to provide a mechanism by which the active mining industry can undertake to remine certain of these abandoned mine areas. Remining is classified as reaffecting previously mined areas in order td extract the remaining coal reserves while improving the environmental quality of these lands through land restogation and abatement of pollutional discharges. However, there currently is a disincentive for operators to plan to extract reserves on these abandoned mine lands which have preexisting pollutional discharges. Therefore, they presently avoid them. This is because of the "potentially unlimited liability of post- mining treatment for any discharges that would remain after mining? (Pennsylvania Bulletin, 1985).

Jan 1, 1987

By John L. Halls

Modern business practice dictates that in order to ensure the economic optimization of investment, the size of any investment venture must be such that every increment of capital invested in such a venture yields at least a corporate minimum acceptable rate of return. This practice is based on the premise that alternative investment opportunities capable of yielding the minimum corporate return are immediately available. If a mining corporation is to make the maximum use of its investment funds, any capital investment in a mining property must comply with the above practice. The most important parameter in estimating ore reserves is the cut-off grade which is used to separate material into ore or waste. The cut-off grade is calculated on the basis that material of cut-off grade produces sufficient revenue to cover the estimated costs of mining and processing through to sales, including depreciation and produce a pre-determined profit. Ore reserves so estimated are adequate for determining the magnitude of an orebody but do not provide a sound basis for determining plant size and therefore capital investment in a new property or for expansion consideration on an existing property. From a financial analysis of this one ore reserve it is impossible to ascertain whether each increment of capital investment is providing the minimum acceptable rate of return, Other difficulties associated with the calculation of a cut-off grade including the determination of depreciation and the amount of pre-determined profit to be included in the cut-off grade calculation are outlined in the text. The proposed solution to determine optimum ore reserves and plant size for new properties avoids the complication of calculating a cut-off grade by computing a series of ore inventories using arbitrarily selected cut-off grades. A comparison of the cash flows generated by production from such ore inventories using incremental financial analysis clearly indicates the ore reserve and plant size which will best serve the corporation's investment and metal production goals. Incremental financial analysis of a corporation's operating mines and prospects assists management in assessing the comparative expansion and investment possibilities of each property for increasing or maintaining metal production on a long term basis.

Jan 1, 1969

By Russel Delmar, Rick Everdell, Harry Charalambu, John Tait

Award of the Design/Build Agreement for construction of Ontario Power Generation’s (OPG’s) Niagara Tunnel Project was made after an intensive 8-month international procurement process. The 14.4-m diameter × 10.4-km long rock tunnel will divert 500 m3/s of water from the Niagara River to the Sir Adam Beck hydroelectric generating complex. The procurement process and Design/Build Agreement included features to address the owner’s requirements regarding risk allocation and cost and schedule certainty, while encouraging innovative ideas from the industry, both technically and commercially. The process included an international expression of interest and prequalification, followed by an invitation for design/build proposals to qualified proponents, and comprehensive proposal evaluations and negotiations with several respondent proponents. An honorarium was provided to the unsuccessful participants in the proposal stage. The resultant negotiated Design/Build Agreement includes Owner’s Mandatory Requirements, negotiated contract terms and conditions, performanceincentive bonuses and liquidated damages for schedule and water delivery performance, a multistaged Geotechnical Baseline Report, joint risk management, references to preexisting community impact agreements and measures to reduce impact on tourism. It also addresses regulatory approvals and permits, an owner controlled insurance policy that required reference to the International Tunneling Insurance Group (ITIG) Code of Practice for Risk Management as a condition of coverage, site specific safety, security and environmental plans, formal team building, a dispute review board, and escrow documentation.

Jan 1, 2007

By Robert Moore Lewis

A unit for separating minerals Into two prescribed size fractions, designated as a Lewis Hydrosizer, was developed at the North Carolina State University Minerals Research Laboratory Ore samples with different mineral compositions, including coal, were separated effectively with the laboratory continuous unit Commercial size units are in operation in North Carolina and Mexico, and under construction In Norway Additional units are being built or are in the planning stage at several companies.

Jan 1, 1983