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By MAHESH SHRIWAS, CHRISTOPHER PRITCHARD

Ventilation monitoring and control in mines are becoming an integral part of day-to-day activity for maintaining the health and safety of miners. This paper evaluates potential real-time monitoring solutions for detecting and reducing diesel particulate matter (DPM), mine fires and dust in situ and examines the state-of-the-art use of ventilation monitoring and control in underground mines for detecting and reducing air contaminants to acceptable regulatory limits. In this study, relevant documents, including research papers, trade publications and manufacturer website information, are reviewed to identify research gaps. This paper also includes evaluations of contemporary sensors (airflow, gas, dust and silica), control system and software technologies, data transport systems, the Industrial Internet of Things (IIoT), ventilation network simulators and control devices to identify potential health and safety research gaps. Examples of some mines in Canada, Australia and the United States that have been using ventilation monitoring and controls are included as well. Overall, this review identifies multiple challenges and research gaps in applying mine monitoring and control systems that could be the focus of future research, offering potential improvements to miner safety and health and financial benefits.

By Wayne Green

The Regional Municipality of York, located north of the City of Toronto in Ontario, Canada, has experienced unprecedented growth during the past decade, with new home construction averaging 15,000 units per year. This rate of growth is planned to continue well into the future with a projected growth of more than 500,000 new residents by 2031, combined with a tar-get of more than 300,000 new jobs to provide a sustainable economic base for the region. It should be noted that York region has been designated as one of the key growth centers by the province of Ontario, aimed in part to meet the housing and employment needs of Canada?s growing population. York Region is a mix of urban and rural areas and is one of the most desirable areas to live in Southern Ontario. York region offers an attractive lifestyle, with its nine municipalities and the amenities created by the many rivers, streams and protected greenbelt areas that encompass more than 69 per cent of the region?s area.

Jan 1, 2010

By Steve Kral

Mining is a risky business. The cost of exploring for new mineral deposits is high and the success rate of finding one worthy of development is relatively low. And once a deposit is identified, there is no guarantee that it will become a mine. Mining companies have to spend a lot of time and money on due diligence, prefeasibility and feasibility studies, and sustainable development and environmental issues before deciding whether the deposit will become a profitable mine. And then there are the millions of dollars spent in developing the deposit and building a mine. No wonder the mining industry has trouble attracting investment capital. Companies take a large risk in developing reserves and investors take a similar risk in investing in them. So mining companies must be as accurate as possible in determining mineralization that makes it to reserve status. After all, reserves are a company’s most important asset and one of the critical factors analysts and funding sources look at when determining if a mine or mining company is worth the risk.

Jan 1, 2003

By M. A. Oskouei

Draglines are the main energy consumers in strip mines. Given the growing cost of energy and environmental concerns, it is important to properly understand dragline energy efficiency. The goal of current research at Missouri University of Science & Technology is to account for operator practice and operating conditions in modeling dragline energy efficiency. This paper presents preliminary correlation analysis and a framework for stochastic modeling of dragline energy efficiency. Thirteen operating parameters (including cycle times, payload, swing angle, and height of dump pile), operator working schedules, operating conditions, and drag, hoist, and swing energies were monitored for an 85 yd3 dragline. Operator effects were examined by two-sample t-tests. The relation between the parameters and energy consumption were assessed by correlation analysis and a stochastic modeling framework has been proposed for dragline energy efficiency. The results show that operator effects are significant (p< 0.05) and energy efficiency is correlated with operating parameters. The completed model will help the coal mines better predict energy consumption, with uncertainty, for different operating conditions.

Feb 27, 2013

By Hassell E. Hunter

The Wyoming Mineral-Conoco Crownpoint Project represents the first time that big hole drilling has been exclusively used to develop totally a privately financed mine below a depth of 1000 feet. Three shafts, one ten feet in diameter and two six feet in diameter, were successfully drilled to depths of 2243&apos;, 2188&apos; and 2188&apos; respectively and cased with hydrostatic designed steel casing. The largest shaft is to be used to handle muck and water from station excavation and enlargement of the other two shafts. A reverse circulation system with potassium chloride base mud was used for drilling. The mud was cleaned by settling in steel lined tanks with assistance by cyclone type separators. Deviation was monitored by gyroscopic surveying at 30 foot intervals and did not exceed 16 inches off plumb. Casing was designed to withstand hydrostatic pressures with a 1.5 safety factor to the large shaft and 1.25 safety factor for the smaller shafts. All casing welds were x-ray tested prior to lowering the casing in the hole. Cementing the annular space completed the operation. The total time to mobilize, drill and move off the three shafts was 363 days. The drilling operation was completed ahead of schedule and under budget.

Jan 1, 1983

The Mining Foundation of the Southwest (MFSW)promotes public understanding and education related to the mining industry. Towards this goal, the Foundation has funded several projects from donations and fundraising activities. The MFSW was incorporated in 1993 by combining the Mining Club of the Southwest and the Mining Club of the Southwest Foundation. The Mining Club began in 1971 as a social organization. It provided members of the mining community an opportunity to meet. The club also provided a means for public education about mining. In the early 1990s, the club’s efforts were directed mainly toward educational activities. And in 1992, discussions began concerning incorporation into a non-profit foundation to further the public understanding of mining. In 1983, the American Mining Hall of Fame was inaugurated to honor significant contributors to the industry and profession. The Hall of Fame serves to educate people about prominent persons associated with the mining industry, present and past. The honorees number 75. Plaques commemorate their induction and are on display at the Arizona Historical Society’s Museum in Tucson, AZ. The combined honors ceremony and banquet have remained one of the fund raising activities.

Jan 1, 1999

By Charlie Yates, Max Ramey, Kurt Nielsen, Michael Hardy

The Yankee Gulch sodium minerals project (YGP) is a solution mining project operated by American Soda. The mine operates on a federal lease administered by the U.S. Bureau of Land Management (BLM). Commercial operations began in November2000. In 1964, Irv Nielsen discovered nahcolite mineralization where the YGP pilot plant is now located near the Piceance Creek in Rio Blanco County, Colorado (Nielsen, 1969).Development of the project accelerated after Williams Corp., of Tulsa, OK, joined with American Alkali in1996 to form American Soda. Pilot testing by American Soda led to commercial permitting, plant design, construction and startup. Figure 1 shows the location of the Yankee Gulch leases and the location of the upper and lower plant sites.

Jan 1, 2003

By A. Noble

The design of separation circuits can be a complex, labor-intensive and costly process. While the engineer?s experience along with extensive data sets and simulation are crucial tools for determining the final solution, a more fundamental approach is suitable to compare preliminary options and reduce the number of potential alternatives. In light of this need, the authors have developed the Circuit Analysis Reduction Tool (CART?). This software package relies on the fundamental principles of linear circuit analysis; however, the solution methodology has been streamlined to automatically incorporate stream splitting and unique separation performance for each unit. The resulting tool allows preliminary analysis of circuit designs without the need of detailed feed characterization. In addition to the basic analytical approach, this paper supports the veracity of the methodology with several simulated examples for various separation models.

Feb 27, 2013

By Ray L. Tobie, Douglas E. Julin

GENERAL DESCRIPTION Block caving is a distinct caving method applied mostly to large, massive, ore bodies because of its in¬herent low cost and high production capabilities. Areas of sufficient size are removed by undercutting so that the mass above will cave naturally. Drawing of the caved ore at the bottom of the ore column causes the caving action to continue upward until all of the ore above the undercut level is broken into sizes suitable for handling. When properly applied, block caving results in a lower mining cost per ton than any other under¬ground method. There are three distinct forms: (1) dividing the horizontal area into rectangular or preferably square or nearly square blocks, drawing evenly over the entire area to maintain an approximately horizontal plane of con¬tact between broken ore and caved capping; (2) divid¬ing the horizontal area into panels across the ore body, retreating by undercutting manageable areas from one end of the panel to the other and maintaining an in¬clined plane of contact between the broken ore and caved capping (thus the name panel caving); and (3) no division of horizontal area of the ore body into defi¬nite blocks or panels (this is termed mass caving). Undercutting may be from wall to wall, retreating from one end of the ore body to the other, maintaining an inclined plane of contact between the broken ore and caved capping. The total active caved area is deter¬mined by the size of block that will not produce undue stress on workings below the undercutting level and by total production requirements. This type of operation is also referred to as panel caving at some properties. SUITABLE ORE BODIES Block caving in its various forms is applicable to deposits of various shapes and ores of various strengths. Its success is governed by rigid requirements and limi¬tations. In unsuitable deposits or where improperly em¬ployed, the loss of ore may exceed that of any other mining method. Good planning, systematic work pro¬cedures, careful supervision, and good judgment con¬tribute to its success. Ore Characteristics Included as a necessary characteristic in an ore body suited to a successful block-caving operation is a proper fracture pattern. Ore hardness should be another gov¬erning factor, and the toughness or softness of the ore should be considered. There must be sufficient horizon¬tal area available for expansion of the undercut, if neces¬sary, to start the caving process. Large, massive, ore bodies usually meet these conditions. Veinlike deposits must be wide and dip rather steeply to conform to the block-caving limitations. The capping must be of such a nature as to cave when the underlying ore is being removed since the weight of the overburden aids in crushing the ore. The most favorable capping character¬istic is that it breaks into coarse pieces and resists attrition as the block is drawn. Soft capping, by breaking into fine pieces and sifting into the ore or channeling through the ore to the drawpoints, can seriously dilute the ore and hinder the extraction of clean ore from the blocks. Types of Ore In block caving, a fairly uniform distribution of val¬ues in the ore is necessary. Grade values may range from low grade to high grade, but most often the sys¬tem is applied to low-grade ores. Wide veins, thick beds, or massive deposits of homogeneous ore overlain by ground which will cave constitute suitable ore bodies. The ore must be such that it can be supported while blocks are being developed and undercut but breaks up readily when caved. Some applications include porphyry copper, disseminated molybdenite, hematite in the Lake Superior iron district, limonite deposits in northern Spain, the diamond mines of South Africa, asbestos and nickel in Canada, and massive magnetite in Pennsylvania. Size and Shape Outline of the ore body should be fairly regular, and the sides of the ore body should dip steeply. It may not be economical to mine small portions of ore extending into the walls of the deposit, and low-grade inclusions in the ore cannot be left unmined. Some dilution of the ore, as mining progresses, by low-grade or barren cap¬ping is inevitable and, unavoidably, some clean ore is left between drawpoints. Determining Cavability The use of rock mechanics is sometimes advantageous in helping to determine the cavability of an ore deposit. The US Bureau of Mines has information and testing ability which can assist in determining the cavability of ore types. Several competent consulting orga¬nizations knowledgeable in rock mechanics can also as¬sist in evaluating the cavability of an ore body. Some recent work has been done to better define the cavability index of various ore bodies; an example of how this was determined is discussed by McMahon and Kendrick (1969). The intensity of the fracture pattern is a critical parameter to be analyzed. The question to be answered is, "How intense must the fracture pattern be?" Table 1 is a tabulation of the size of rock fragments that appear at the drawpoint of various block-cave mines around the world. These are indicative of the fracture-pattern spac¬ing and, as can be seen, they vary substantially from the almost sandy material at the Mather mine to fairly sizable blocks at the Grace mine. Several sets of fractures are essential to promote good caving. Ideally, two vertical sets at nearly right angles to each other and a third set nearly horizontal are required to insure a good caving ore body. Since initial caving of an ore mass is almost always by the action of gravity acting on these planes of weakness, it is doubtful

Jan 1, 1982

By Staff

The mineral sector is a fundamental part of the U.S. economy. It contributes to the real gross domestic product (GDP) at several stages—basic (mining), intermediate processing, manufacturing of finished goods and construction. The estimated growth rate for the real GDP of the United States for 2006 was 3.2 percent. The nominal GDP was about $13.2 trillion. The value of minerals mined in the United States in 2006 rose significantly because of increased unit price for some metals—particularly copper, zinc and other base metals. There was also a significant reduction in metals stocks. Infrastructure expansion and manufacturing in China and India have been absorbing a significant portion of world output. Domestic production increased for some industrial mineral materials, mainly cement and construction sand and gravel. Production of crushed stone declined less than 1 percent in 2006 compared

Jan 1, 2007

By Antonio Raschillà

On the 2nd of June 2007 SELI S.p.A. started the excavation of Beles Tailrace Tunnel (Ethiopia). The new 8,07 m diameter DS Universal TBM utilized for the tunnel excavation was manufactured by SELI S.p.A. and allowed the installation of 30 cm thick concrete lining, contemporaneously with the excavation of 7,200 m of tunnel. The greatest part of the tunnel alignment was excavated in hard and sound basal-tic rocks. The paper describes the main steps of the tunnelling operations which led to a remarkably rapid excavation, with a peak production of 36 m / day and a final break-through achieved 46 days ahead of the contractual deadline. Furthermore the paper describes the work and logistic organization that was set up to efficiently perform the mechanized excavation in the very remote area of the project.

By R. Chen

Most tunnels built in Sydney encounter similar ground situations; they penetrate either the Hawkesbury Sandstone or the shales that lie beneath the city. Tunnels in these materials are generally sup-ported by rock bolts in combination with a shotcrete lining. A method of analysis is presented to improve our understanding of the long term behaviour of fiber reinforced shotcrete (FRS) materials and the tunnel support systems. A finite element method SAFEA (Semi-analytical FE Analysis) is developed to model the combined creep behaviour of a shotcrete lining and the Hawkesbury Sandstone. To model the time-dependent creep behaviour, the bulk modulus and shear modulus of the materials are represented by logarithmic functions in time. A Laplace transform is then applied to these functions of time and the solution of the problem found from a finite element analysis. Tablot?s method is then used to invert the transformed values and find the solution in real time. The time dependent creep deflection of the numerical tunnel models reflects the interaction of the shotcrete lining and rock which have different creep parameters.

Jan 1, 2008

By Bill Cain, R. John Caulfield, D. Scott Kieffer

The East Bay Municipal Utility District is undertaking seismic upgrades of the Claremont Tunnel in the San Francisco Bay area. The tunnel carries treated water across the active Hayward Fault to supply a major metropolitan area. Studies indicate the tunnel could be severed by fault offset during a major seismic event. A design approach to achieve limited operation of the tunnel following fault displacement has been established and design details are currently being evaluated. This paper describes the project, the design approach, and summarizes significant construction constraints.

Jan 1, 2001

By Steve Kral

Borates are minerals that contain boron. Trace amounts exist in rocks, soil, water and people. Boron-containing ores are rare and U.S. Borax, a subsidiary of Rio Tinto Borax, controls one of the world’s two world-class borate deposits. Through its global systems of mines, refineries, ports, sales offices and distribution centers, the company supplies nearly 45 percent of the world’s demand for borates. Borax has been mining borates in California for more than a century. This year the company celebrated 131 years of continuous business in the Golden State and 76 years at its operations in Boron, the site of California’s largest openpit mine. It also has mines and refineries in Argentina, refineries and ship-ping facilities in Europe and technical staff in the United States, North and South America, Europe and Asia Pacific. So, with the 130±years of borate mining and processing experience behind it as well as its global marketing and distribution centers, there is very little that Borax does not know about borates.

Jan 1, 2003

By C. J. Newman

Before 1995, the smelting process at the Kennecott Utah Copper Corp. (KUCC) smelter consisted of Noranda reactors and Pierce-Smith converters. When considering expansion, it was decided that the existing process would not lend itself to a program geared toward processing the total output of copper precipitate and copper concentrate from KUCC mining and concentrating operations. During 1989 and 1990, several smelting options were evaluated. The final selection was the Outokumpu flash smelting process, coupled with the new Kennecott-Outokumpu flash converting technology. Facilities were designed and installed to process 1 Mt/a (1.1 million stpy) of copper concentrate, with the ability to expand to 1.2 Mt/a (1.3 million stpy). The smelter facility that used the Noranda technology was shut down in May 1995. The flash smelting furnace operation began in June with the flash converting furnace start-up a few weeks later.

Jan 1, 1999

By M. L. Tucker, William H. Langer

Many countries, provinces, territories and states in the European Union, Australia, Canada, the United States and elsewhere have begun implementing sustainability programs. Most of those programs, however, stop short of sustainable management of aggregate resources. Sustainable practices do not always have to be conducted under the title of sustainability. This case study describes how Lafarge implemented the principles of sustainability even though there was an absence of existing local government policies or procedures addressing sustainable resource management. Jefferson County is one of three counties in the six-county Denver, CO, region that has potentially available sources of crushed stone. Crushed stone comprises 30percent of the aggregate produced in the area. And it plays a major role in regional aggregate resource needs. Jefferson County is home to four of the five crushed stone operations in the Denver region. Lafarge operates one of those four quarries.

Jan 1, 2004

By J. O. Marsden

Parts I and II in this series of papers presented the chemistry of medium-temperature pressure leaching of copper sulfide concentrates and reviewed the metallurgical development of a process to effectively recover copper using medium-temperature pressure leaching and direct electrowinning (DEW). Key features of the process were the use of superfine grinding of the concentrate (to a P98 of 12 to 15 µm and P80 of 6 to 7 µm), pressure leaching at 160ºC and 1,380 kPa (200 psi) oxygen overpressure, DEW to produce LME Grade A cathode, recycling of the lean electrolyte to the pressure leaching step and treatment of a lean electrolyte bleed by solution extraction (SX). Recycling of the lean electrolyte provided all of the acid required to effectively dissolve copper and convert approximately 65% to 70% of the sulfide sulfur to elemental sulfur, resulting in an ?acid-autogenous? process referred to as the ?MT-DEW-SX? process. This paper (Part III) discusses the steps taken to develop and complete a large-scale demonstration of the process at Bagdad, Arizona, in 2005.

Jan 1, 2007

By J. Kretschmann

Around the world, mining has been done for thousands of years for the benefit of humankind. The winning process in mining operations ends with the depletion of the deposit or its closure if the operation becomes economically unprofitable. After that, a period of post-mining follows which may last for a very long time and which is generally regarded as a period of hazards, risk and high cost. In the USA alone, approximately 500,000 abandoned mines do exist; worldwide, there are millions. In Germany, too, we have had to deal with abandoned mines for a considerable period of time now.

Jan 1, 2012

By F. Habashi

The changes that took place in China between 1984 and 2004 are remarkable. Visits were made to universities, research institutes, metallurgical industry, and many cultural centers within five trips during this twenty years period. The impressions of these visits are outlined.

Jan 1, 2007

By R. Hipsley, D. Arbonies, P. Dobak

South Arturo is a “Carlin-type”, breccia-hosted, oxide gold deposit located at the north end of the Carlin Trend. The discovery hole was drilled in July 2005 from mine dumps 1,000 feet south of the Dee open pit. Discovery hole (BD-72) encountered a cumulative 245 feet @ 0.056 opt Au beneath 850 feet of post mineral Tertiary Carlin Formation. Oxidation extends to depths greater than 2,000 feet in the deposit area. The deposit is presently in definition drilling stage with approximately 190,000 feet of drilling completed to date. A resource estimate is in progress. This paper will focus on the discovery and descriptive characteristics of the mineralization.

Jan 1, 2007