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Lime production is the largest single chemical use for limestone and dolomite. The term “lime” in this review refers to high-calcium and dolomitic quicklime, their hydroxide forms and dead-burned dolomite. This review is restricted to a discussion of the U.S. lime industry. Production and consumption In 2004, according to preliminary data, U.S. lime production was about 20.1 Mt (22.1 million st), an increase of 900 kt (990,000 st) compared with 2003. Production in2004 was valued at about $1.4 billion. Commercial sales of lime totaled 18.6 Mt (20.5 million st) and captive production was 1.5 Mt (1.65 million st). Total U.S. consumption was about 20.2 Mt (22.2 million st). The majority of U.S. lime trade was with Canada.

Jan 1, 2005

By B. K. Belle

The beginning of 21st century has heralded the global strategic importance, as evidenced by increase in energy prices and energy generation-emission-utilization dilemmas. In January 2008, the South African energy supplier, ESKOM had tabled the concept of power conservation and acknowledged the energy crisis until 2016. The concept is required of all energy users to reduce their electricity consumption, intensify energy efficiency and cautiously proceed with new projects. The generation of energy results in by-products called ?green house gases? (GHGs). To make a positive response to climate change and their effect on the environment, every energy user must ensure efficient energy use through technical and administrative means referred to generally as energy savings. This paper identifies mine ventilation engineering, in particular the electricity consumed by main fan units, as an area of potential energy savings. For a major mining company, electricity consumed by main ventilation fans alone can be in the order of 120 MW. Although a known fan engineering technique but scantly applied technology identified as the Hermit Crab can be seen as a ?quick win? project, due to its success in other industries such as cement and steel. The ?Hermit Crab? technique® involves upgrading or replacement of an impeller - whatever its origin - with a design impeller to suit the actual ventilation requirements, resulting in increased fan efficiencies. The cash flow benefits associated with a case study and its rollout of this technology have been calculated. For a 10% increase in main fan efficiency, would have a net present benefit of US$ 16.08m over 10 years. With the inclusion of carbon credits, this benefit rises to US$ 29.40m in total. Application of other available technologies, viz., composite materials, ventilation-on-demand and variable speed drives are discussed.

Jan 1, 2009

By K. Oraee

Rate of penetration of Tunnel Boring Machines (TBM) has a significant role in the planning, measurement of productivity and performance of any tunneling project. In this paper, the application of Adaptive Neuro Fuzzy Inference System (ANFIS) in prediction of TBM penetration rate is evaluated. For this purpose, a database including Rock Quality Designation (RQD), Uni-axial Compressive Strength (UCS) of the rock, the Distance between Planes of Weakness (DPW) in the rock mass, and empirical data regarding rate of penetration of TBM from several tunneling projects are collected. The Rate of Penetration is then estimated by using ANFIS. These results are then compared with measured TBM penetration rates (actual data). It is concluded that ANFIS can be applied successfully for such purpose and result in high accuracy for prediction for the rate of penetration of TBM. The method provided in this paper can assist the mining engineer to estimate the performance of tunneling accurately.

Jan 1, 2012

By M. C. Roberts

Currently, mineral producers are suffering through a major downturn in prices for their products, even though it has only been a few years since they were enjoying high prices. From an historical perspective, the current situation is another of the cyclical down-turns that often reoccur every 5 to 7 years or so. This paper uses time trend decomposition techniques to identify the cycles and statistical methods to find the duration of these cycles for a variety of mineral prices. Given some idea of how long and severe these cycles typically are, the mining industry can better plan to weather the downturns and take advantage of the upturns. For example, timing investments in new projects to take advantage of the cyclical upturns can dramatically improve project profitability.

Jan 1, 2000

By S. Lähteenmäki, P. Koivistoinen, J. Levanaho

Semi Autogenous Grinding (SAG) circuit is the most common grinding circuit to day. In Europe and South Africa fully autogenous (AG) circuits are also popular. SAG circuit has a lower capital cost and simple operation. SAG circuit requires the use of grinding balls, which increases operating costs and decreases availability. An AG circuit may produce a higher Net Present Value to the investment. The AG circuit is more complex to design and operate. However, operating experience from AG circuits illustrates that an AG circuit can be as trouble free as a SAG circuit with the benefit of lower operating cost.

Jan 1, 2001

By Howard J. Handewith

Long used in mine development in England, Europe and Russia, roadheaders are growing in size, features, productivity and application. Beginning with the basics, this paper covers the economic and the technical aspects of the new roadheaders in both mine production and development. The author explains how to choose and integrate roadheaders into ongoing operations as another step in the inexorable march from labor to capital intensive mining. Innovations now on the drawing boards are covered that are the challenge of the future.

Jan 1, 1983

Most statistical and geostatistical methods of re-source and reserve estimation work extremely well for Normal (Gaussian) well-behaved information. However, most interesting mineral deposits exhibit far from this idealistic distribution of values. It seems that the more valuable the mineral, the less likely the data are to have a Normal distribution. Values tend to be "positively skewed" with a long tail into the high values. Using averaging techniques, such as inverse distance or ordinary kriging may result in consider-able overestimation of grades and tonnages unless such values are cut or otherwise modified. This paper presents some real case studies where distributions are (a) highly skewed and (b) the product of multiple phases of mineralisation. Practical methods are presented for solving such problems including combinations of indicator and log normal kriging methods. The emphasis of the presentation is on developing operational methods which can be used on project evaluation or grade control in producing mines.

Jan 1, 2000

By R. C. Freas

Composite materials are finding new applications daily, ranging from automotive parts to synthetic lumber. The variety of applications seems almost limitless. However, these emerging products bring both new opportunities and new challenges to the field of industrial minerals. One of the primary challenges is from alternative materials other than industrial minerals. Thus the question is asked whether industrial minerals will truly benefit from the growth in market applications for composite plastics. This article highlights some of the opportunities for industrial minerals while focusing on performance and competitive demands on mineral products intended for use in this developing market.

Jan 1, 2000

By Y. Wang

China is a big mining country with a long mining tradition and history. At present, there are nearly 200,000 different mines and 21 million workers. The total production value of mining makes up 6% of GNP. With the development of economy, the mining industry has played a more important role in our economic market, supplying more than 95% non-reusable energy, 85% of industrial and agricultural raw materials, over 75% of fertilizers and 30% industrial and agricultural water.

Jan 1, 2001

By Philip-Mark Spanidis, Christos Roumpos, Francis Pavloudakis

This paper presents a quantitative research (QNR) methodology, collaboratively conducted with a group of mining experts, to assess the knowledge management (KM) landscape in the Greek mining industry. The methodology involves a framework for structured data collection using questionnaires, statistical analysis, discussion on critical methodological aspects, and interpretation of results focusing on key aspects of interest for designers of KM systems. The paper concludes by summarizing the methodology’s outcome and proposing perspectives for further research.

Aug 1, 2024

By Stephen Davies

Mining at Hudson Bay Mining & Smelting's Snow Lake Division is now in the mature stage of the mines' lives. These base metal copper-zinc mines have been operating for more than 30 years. Stopes had small pillars called "crown pillars" left between them. These pillars range up to 100 m (330 ft) long by 40 m (130 ft) wide and 15 m (50 ft) thick. Hudson Bay have been successful in removing these pillars by using cable slings, electric scoops, longhole mining and diesel load-haul-dump equipment. The different shapes and sizes of these pillars has required that many innovative techniques be tried in order to find acceptable economic mining methods. An overview of the different methods will be outlined. Background Hudson Bay Mining & Smelting's Snow Lake Division is located in Manitoba some 800 km (500 miles) north of Winnipeg and 200 km (125 miles) by road from the Hudson Bay smelter complex located in Flin Flon, Manitoba (Fig. I). There are currently three producing underground mines and one open pit operating at the Snow Lake Division, producing copper and zinc concentrates. Pillar recovery is intensive and vital to continued production of these mature mines. The crown pillars are producing more than 50% of the current mine production. This figure will increase in the future. The two mines at which crown pillar recovery is taking place and that will be discussed are the 400 t/d (440 stpd) Rod Mine and the 1000 t/d (1100 stpd) Stall Lake Mine, both five-day-a-week producers. Crown pillar mining has been applied for some time at these mines. However, it was only recently that the crown pillars became vital to production. This has necessitated a number of innovative techniques to recover them.

Jan 1, 1992

By Graham Davis

The future of the world's minerals industries is often painted as bleak. Peter Drucker has repeatedly proposed that the demand for minerals has become "uncoupled" from world economic growth.' This implies that, while mineral demand was in the past linked to the growing demand for and consumption of goods and services, further world development will not require substantial mineral inputs. Lester Thurow noted that for these reasons the US minerals industry is diminishing in scale and economic importance.2 There is some documented evidence of such uncoupling, and the demand for minerals may indeed diminish in the future. But such announcements are, to this point, no more than speculation. For instance, is it not just as likely that renewed environmental concerns will cause increased demand for the relatively innocuous environmental properties of metals, replacing plastics? And even if the prophesied demand decreases do occur, a sufficient fall in metal prices due to technological advances could increase the quantity of minerals demanded above current levels, in spite of leftward shifting demand curves. Thus, worldwide mineral production activity may increase or decrease in the future and no one can say whether more or fewer of the earth's citizens will become involved in the extraction and processing of minerals.

Jan 1, 1994

By Georgene Renner, William R. Yernberg, Steve Kral

Advanced Terra Testing (ATT)is a full-service geotechnical testing laboratory. It specializes in rock and soil mechanics and geosynthetic materials testing. ATT provides services to the global mining industry. The company has performed more than 1,000 projects for more than 300 commercial and government clients. Services include coal pillar design testing, leach pad material and performance testing, tailings pile consolidation testing and closure and remediation services. Rock and soil mechanics tests include unconfined and triaxial strength, shear and tensile strength, permeability, index testing, consolidation, liquifaction potential, elastic moduli determinations, heap height versus percolation rate, long-term batch testing and dynamic loading tests.

Jan 1, 2003

By Stephen C. Tadolini, Colton Cook, Cody Hildreth, Frederick Cybulski

"Broken and jointed ground is extremely hazardous and requires unique stabilization techniques to protect worker and critical entries. Bolting techniques, even the most advanced with pre-load to create roof compression, can leave large gaps of unconfined and separated roof. This roof can also be susceptible to water inflows which only exacerbate the support problem. These types of conditions existed on long term development main entry accessing several future longwall panels. The geotechnical assessment identified well-defined jointing systems that also permitted water to flow between the roof separations, which “lubricated” the roof material and minimized any frictional advantages. Chemical injection of a Polyurethane material, Minova Carbopur WS, was placed beyond the bolted horizon to move the water to the rib lines and reinforce the fractured and broken roof. The injection material permitted the effective use of bolting patterns and helped ensure long-term stability of these critical entries. The paper describes the evaluation techniques, design patterns, basis for chemical selection and application, and results and recommendations.BACKGROUNDThe injection of mine and underground civil structures using polyurethane (PUR) has been ongoing for over 50 years. The applications in mining have included gate road stabilizations, longwall set-up and tear-down entries, and simple consolidation of coal mine roofs. PURs have also been used for roof stabilization during longwall shield recoveries. Polyurethane injection was initially developed by the Bergbau-Forshung GmbH, a German coal mine research institute, in the early 1960s (Jankowski, 1972). The product became a standard stabilization method in Germany after its commercial introduction in 1971 (Knoblauch, 1994), and was successfully manufactured at the Minova Essen, Germany location for over 50 years. With the recent closing of the German underground mines, that manufacturing facility has been closed and moved to Katowice, Poland, where production continues today Injection products are also being successfully manufactured by Minova in Australia and the United States.Polyurethane injection in underground coal mines is used in difficult ground conditions in fractured immediate and main roofs. It is also common as a rock stabilization remedy to prevent longwall face caving during shield removal. As presented in the case study, polyurethane was applied to minimize the inflow of water from beneath a stream channel while providing reinforcement and consolidation of the fractured roof that had lost confinement. Polyurethane is a two-component system (Part A and Part B) that is injected into a borehole and can chemically bond to the rock, not relying on friction or mechanical interlock to provide support. The material is injected under pressure, coupled with a low viscosity and small particle size; it flows into roof fractures and separations, which are the paths of least resistance. New developments in low viscosity PUR materials allows penetration of cracks as tight as 0.002 inch (0.05 mm) wide. This also allows for the closures of extremely small cracks to minimize the inflow of water, even if the water is under pressure. Combinations of designed expansion properties and low viscosities make the materials ideal for minimizing and stopping flows of water from underground structures."

Jan 1, 2019

By R. Kramer, A. Habibi

"Diesel Particulate Matter (DPM) measurements were taken at Tronox’s Westvaco Trona mine in Wyoming. Both shift-average and real-time monitoring using Elf pumps and Airtec analyzers, were used. The mine’s underground transportation fleet consists of more than 250 diesel-powered vehicles. A vehicle monitoring log tracked fleet usage during the test; logged data consisted of vehicle type, direction of travel, and time. The log was used in analysis to determine the DPM spread rate, of normally operating equipment, in the different entries with respect to vehicle location. Airflow velocity measurements at the stations were taken during the survey. The survey results also identified vehicles with higher emission rates. An ECOM gas and a MAHA DPM analyzer, both located in the mine’s underground emission shop, were used to obtain various vehicle emission rates. The correlation of the workshop and field measurements was investigated with regard to the machine activity, fuel usage and atmospheric conditions. The results were used to identify and execute a ventilation project to reroute 45% of diesel shop air back to intake entries, by interlocking an automated door and a regulator. The result is reduced DPM downstream. INTRODUCTION DPM has been classified as a potential occupational carcinogen by the National Institute for Occupational Safety and Health (NIOSH).The Mine Safety and Health Administration (MSHA) rule governing DPM exposures in metal and nonmetal mines cites total carbon (TC), a summation of elemental carbon (EC) and organic carbon (OC) obtained by NIOSH Method 5040, as a surrogate for determining DPM exposures (Noll, 2006). MSHA personnel use the 1973 sampling criteria outlined by the American Conference of Government Industrial Hygienists (ACGIH) for collecting compliance-based respirable and inhalation samples in metal/nonmetal mines. Instrumentation developments are allowing improved real time monitoring of ventilation parameters. DPM is within the aerodynamic particle size range of the samplers used for respirable and inhalable dust measurements. If a sampler used by MSHA to collect inhalable or respirable dust samples in underground metal/nonmetal mines was used to collect DPM, both the DPM and mine ore dust would accumulate on the sample filter (Noll, 2006). To comply with the requirement and lower the DPM exposure, mines are implementing a variety of control technologies such as emission based maintenance programs where adjustments or repairs are performed on the vehicles (McGinn, 2000)."

Jan 1, 2016

By Daniel Connor, O&apos

The Cal-Sag Relief Sewer is a 2.6 m (8 ft 6 in.) diameter 9.1 km (5.7 mile) rock tunnel bored in dolomite for the Metropolitan Sanitary District of Greater Chicago. Included in the project are 18 shafts varying in depth free 70 m (230 ft) to 41 m (135 ft). This paper discusses how Healy/Vanessa reduced costs by eliminating conventional hand excavation by hoisting muck from a high production Robbins TBM (Tunnel Boring Machine) through small diameter drilled shafts and using a trailing rail-utility backup system.

Jan 1, 1985

By H. A. Taylor

Graphite is elemental carbon that crystallizes in the hexagonal system as six-sided platelets. It occurs naturally and is mined. And it can be made artificially from petroleum coke in the form of shapes (electrodes) and powders. The market for most kinds of graphite in most end-uses was good in 2004. The 2005 graphite market looks positive. The major graphite prices, as given in Industrial Minerals, remained unchanged throughout the year. The preliminary 2004 U.S. Geological Survey (USGS) prices for natural graphite showed almost no change for crystalline flake. They were $600/t ($544/st) in 2004 and$622/t ($564/st) in 2003. Mexican amorphous graphite was almost unchanged at $150/t ($136/st) in 2004 from$152/t ($138/st) in 2003.

Jan 1, 2005

By H. Huang, Y. Takasaki, R. N. Gow

"The presence of enargite (Cu3AsS4) is problematic in gold processing not only because it is environmentally hazardous due to its arsenic content but also because it is refractory, causing both cyanide and oxygen consumption to increase. Selective leaching and treatment of the arsenic would prove advantageous prior to applying conventional gold leaching methods. The reactivity of enargite samples from Butte in Montana and Quiruvilca in Peru were spectroelectrochemically studied under alkaline conditions – pH range of 8-13 – using Raman spectroscopy and cyclic voltammetry. Raman spectra of the surface were collected during and after potentially cycled voltammograms in order to determine and compare surface species against theoretical EH-pH diagrams constructed from mass-balanced thermodynamic calculations using STABCAL software. Under slightly oxidizing conditions, covellite (CuS) peaks were found in a short matter of time, above ~100mV vs. SHE for pH 9-13, suggesting arsenic leaching specifically occurred. At longer conditioning times, elemental sulfur was observed and tended to passivate the surface. The presence of elemental sulfur suggests that copper was eventually leached from the surface. By operating above pH 12, under slightly reducing conditions near -300mV vs. SHE, arsenic can be selectively leached as thioarsenate (AsS4 3-) or thiosulfate (AsO4 3-) without sulfur formation.IntroductionEnvironmental limitations on the pyrometallurgical processing of ores and concentrates bearing arsenic and other hazardous elements often outweigh those in hydrometallurgical processing, particularly when minerals like enargite (Cu3AsS4) are present. The hydrometallurgical processing of enargite-bearing materials can be broken down into two categories: the co-dissolution of arsenic and copper under acidic conditions, and the selective leaching of arsenic under alkaline conditions. The selective leaching of arsenic would preferably leave behind copperrich sulfide phases, typically chalcocite (Cu2S) and covellite (CuS), which then become more amenable to conventional copper (and gold) processing. Furthermore, selective leaching often employs sulfide (S2-), bisulfide (HS-) or polysulfides (Sx 2-) to first extract the arsenic as AsS4 3- and AsS3 3- (Delfini et al., 2003; Anderson and Twidwell, 2008; Tongamp et al., 2010a,b). However, hypochlorite leaching (Viñals et al., 2003; Curreli et al., 2005; Mihajlovic et al., 2007), ammoniacal leaching (Gajam and Raghavan, 1983), and finegrinding to mechanically activate the enargite surface (Balaz and Achimovicova, 2006) have been investigated to increase the normally slow reaction kinetics. Because gold ores are becoming more refractory due to increasing arsenic contents as a result of enargite, these methods are being examined more closely by the gold-mining industry."

Jan 1, 2015

By Rudolph K. Hoagberg

Silica sands, primarily in coarse size ranges, are used to prop open fissures or voids created in the bedrock by hydraulic fracturing. This procedure increases the flow of gas or oil or other fluids through the bedrock. The sands used must meet various specifications relating to their physical and chemical characteristics; these characteristics are in turn related to the geologic provenance of the sand deposit. The Jordan Sandstone, a Cambrian formation which is exposed in Minnesota and Wisconsin, meets the specifications of a proppant sand by virtue of its depositional history and its sedimentary properties.

Jan 1, 1980

By N. C. Trivedi

Natural calcium carbonate, commonly known as limestone is an abundant resource pretty much worldwide. Calcium carbonate occurs naturally as the main constituent of chalk, limestone, and marble. One of the unique characteristics of this abundant mineral is its versatility. Major markets for calcium carbonate are: paper, plastics, caulks and sealants, carpet backing, paint, and food additives. This broad spectrum of consuming industries has warranted producers of this industrial mineral to be innovative and quality focused simply to meet the ever increasing demands for performance. This need for improving performance of calcium carbonate has led to the development of new sources of calcium carbonate, natural as well as synthetic.

Jan 1, 2002