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By K. C. Tran

This paper reviews the advancement of measurement technologies for the control of raw materials processes in the basic industries. The combination of digital technology and on line spectroscopy enables the development of intelligent instruments for composition and particle size analyses in real- time high- frequency control conditions. In many industries, the applications result in productivity improvement and energy savings. Plant specific examples include operating experience and benefits realized in sorting, blending and beneficiation processes. Instruments of the future not only measure specific parameters of the process and monitor its own health combined with self-corrective mechanics but also acts with intelligence to effect the quality of the process or regulate the primary apparatus.

Jan 1, 2001

By K. E. Kolm, W. H. Langer

Developing natural aggregate resources (sand, gravel, and stone) creates environmental impacts. A systems analysis method has been designed to characterize the components of the environmental system, identify potential impacts to those systems, and evaluate the extent of those impacts. The step-wise method consists of problem definition, data collection, preliminary conceptualization and characterization, additional data collection, data analysis, and refinement. The method requires analyzes of various systems making up the environment, including land surface, geomorphic, subsurface, and groundwater systems. After system characterization is complete, the method focuses on identifying and evaluating potential environmental impacts to determine acceptable mining strategies.

Jan 1, 2001

By T. J. Batchler

Deformable materials are sometimes added to ventilation stopping constructions to prevent damage caused by convergence in coal mines. However, adding deformable materials can significantly reduce the capacity of a stopping to resist transverse loading. As part of its mining health and safety program, the National Institute for Occupational Safety and Health (NIOSH) has conducted research on the effect of various materials with different deformation properties on the transverse loading capability of a stopping wall. Based on a three-point hinge method of failure, a half-wall method of testing in the NIOSH Mine Roof Simulator was used to simulate full-scale wall behavior. This simulated the fracture initiation and eventual failure of the stoppings from transverse loading. The impact of the modulus of elasticity of various deformable materials was examined in this study. A polystyrene foam block with a low modulus of elasticity, which is commonly used as a deformable material, was shown to degrade the transverse load capacity of the stopping by as much 95%. Other materials with higher modulus of elasticity preserved more of the transverse load capacity of the stopping, but were not able to absorb as much convergence. This paper presents the results of a parametric study that quantifies the impact of various deformable materials in block stopping construction under transverse load conditions. Disclaimer: The findings and conclusions in this report have not been formally disseminated by the National Institute for Occupational Safety and Health and should not be construed to represent any agency determination or policy.

Jan 1, 2009

By M. D. Khattar

Problems discussed concern encountering of high temperatures [up to 66°C] and heavy flow of water [150 L.P.S] during the construction of the 10.15 MØH.R.T. for the 2500 MW Nathpa Jhakri Hydro Power Project in the Himalayas(India). Over a length of 2500 M progress of work got seriously affected resulting in excessive time for completion - two years [max. monthly progress achieved was 178 M [Heading]. Many innovative and simple steps were taken to complete the work in these inhospitable environs affecting working of both men and machines. Also it meant a review of the design of concrete lining. Other geological conditions affecting the progress are also described.

Jan 1, 1999

By L. Alan Weakly

Global warming is a political reality in the United States today. The actual impact of the continued utilization of fossil fuels is not known and is open to debate. However, the growing concern about the continued use of these fuels is problematic. There are technologies available to us today that would permit America to meet its future energy demand and not contribute to global warming. The inconvenient reality is that fossil fuels cannot completely be replaced with energy conservation and the use of wind, solar, hydroelectric, geothermal and nuclear energy. The connection between the greenhouse effect and global climate change was first identified by physicist John Tyndall in the 1860s. To prove the greenhouse hypothesis, Roger Revelle and his research team started measuring carbon dioxide concentrations in the earth?s atmosphere in the early 1960s (Becker, 2007). With the rising concern about global warming, scientists throughout the world have been obtaining surface and air temperature data. Scientists have also been comparing CO2 concentrations found in glaciers throughout the world with theorized annual temperatures. Data for both dates back 1,000 years. Armed with this data, many nations of the world and the United Nations Intergovernmental Panel on Climate Change (IPCC) have concluded that climate change is a reality. The IPCC also concluded that this climate change is the result of mankind?s consumption of fossil fuels and that catastrophic consequences will occur on a

Jan 1, 2008

By J. Piper

Markets and Production Beryllium (Be), an extremely light metal, is used in many specialty applications. It the lightest element in Group 2A of the periodic table, with a specific gravity of 1.85 gm/cc, and a high melting point of 12850C (Calvert, 2004). The functional properties of beryllium are stiffness, strength, dimensional stability, resistance to corrosion from acids, and electrical and thermal conductivity. The ability to reflect neutrons and transmit x-rays, makes beryllium irreplaceable in uses such as precision optical components, inertial guidance systems, and in nuclear reactors (Anon, 1993). Beryllium is used in Cu alloys to strengthen and reduce corrosion in copper wire, and in lightweight oxide ceramics that are used as heat sinks, and as electrical insulators. The market revenue of beryllium can be broken down into the seven major groups below, and are plotted on the pie chart in Figure 1 (Anon, 2005). 1.) Telecommunications & Computer 2.) Magnetic & Optical Data Storage 3.) Aerospace and Defense 4.) Automotive Electronics 5.) Industrial Components 6.) Appliance, and 7.) Other.

Jan 1, 2007

By K. Fleck

Energy West Mining Company (EWMC) has implemented a geologic program for improving stability and support requirements along deep two-entry longwall gateroads at its Deer Creek Mine operations located near Huntington, Utah. Together with geotechnical monitoring and concurrent review of mine seismicity in cooperation with MTI staff, it has become possible to improve longwall layout designs for two seam extraction of the Hiawatha and Blind Canyon seams. The geologic program consists of surface and in-mine exploration drilling, surface and in-mine geologic mapping, rock mechanics testing and detailed measurements of changes in depositional and structural conditions during development of every longwall gateroad. The geotechnical program consists of underground measurements at seven locations in two neighboring mining districts located in the Hiawatha and Blind Canyon coal seams under moderate to deep cover. Within the last five years, additional measurements, including data on seismicity and face conditions, have been incorporated into the data collection program for verifying the insitu coal strength and load transfer mechanisms for improving two-seam designs and support systems. Geologic mapping results are also used to predict local stability of headgate and tailgate entries, combining mine roof mapping, stratigraphic profiles of the coal and roof, and depth-of-cover information and dual-seam mine overlays, for use by operations personnel in planning roof and rib support for the retreating longwall sections.

Jan 1, 2012

By Don Dodds

Iron Mountain Mine Rehabilitation Project Brief History The Iron Mountain Mine is located in Northern California approximately 12 miles northwest of Redding. The ore body is a large, very dense pyritic intrusion, discovered in 1860, and initially minded for silver. The silver played out quickly and 34 years later the ore body was mined for copper. Copper mining was scheduled to cease in 1939, but WWII prolonged the closure. After WWII, the pyrite ore was mined to produce sulfuric acid. In 1949 when large amounts of cheaper sulfuric acid were being generated by the oil industry the underground mine shut down. Little was done with the site conditions until 1970 when the U.S. Bureau of Mines began monitoring the pH of the effluent. The initial pH readings were around 2.0. This was lower than anyone expected. Laboratory tests showed that when the ore from the mine was submerged in water, the pH of the water would stabilize above 4.0. However, the pH got steadily lower. In 1989 with the ph around 0.7, the U.S. Environmental Protection Agency (EPA) required the owner to build a capture and treatment facility. During this initial period, the majority of the effort was spent on the treatment plant. The relationship between the mine owner and the EPA was basically an adversarial relationship from the very beginning. In 2001, North Pacific Research was hired to upgrade the capture and control facility. The general layout of the Iron Mountain Mine is shown in Figure 1.

By Q. J. Browne, M. A. Miller

Silver Bell produces about 22,000T of fine copper annually from low-grade chalcocite and oxidized copper ore that is recovered by sulfuric acid leaching and SX-EW processing. The current mineable reserves are 146 million short tons averaging 0.39% Cu, at a 0.15% cutoff. Silver Bell utilizes two types of mining methods to develop the low-grade reserves: (1) a conventional blast, load and haul method for run-of-mine leach ore, and (2) rubblization of material on the margins of existing pits. Rubble leach ore is blasted, terraced with a bulldozer, and leached in place. Mining and/or rubble leaching is currently active in four separate pits. Laramide-age intrusive rocks host porphyry copper mineralization at Silver Bell. Quartz monzonite porphyry dikes and stocks, mafic-poor equigranular granite (alaskite), and sub-volcanic dacite porphyry are the predominant host rocks. Most of the ore currently mined comes from near-horizontal enrichment zones containing veinlets and disseminated grains of pyrite and chalcopyrite rimmed by chalcocite. Conversion from a milling operation to a leach only operation allowed for a much lower cutoff grade than was historically used at Silver Bell. Mine geologists were able to increase copper resources by drilling exploration targets that were previously interpreted to provide lower-grade mineralization below cutoff-grade for milling. Geologic parameters that effect the distribution of rubble and mineable leach ore include: ore grade and thickness, variable alteration styles in intrusive host rocks that affect fragmentation during blasting, acid consuming carbonate wallrocks (reactive skarn) which influence leach solution pH, solution flow paths and drainage, presence of leachable oxide mineralization in non-reactive skarn, and depth to hypogene mineralization which is currently uneconomic. Geologic parameters are used to predict rubble bench limits, vary blast hole spacing for consistent fragmentation, and correct errors in mineral zone classification based solely on blast hole assays. An expansion-drilling program has identified approximately 150 million tons of new leachable copper resources with an average grade of 0.35% Cu.

Jan 1, 2002

By M. Menéndez

Enhanced gravity separation appears to be one of the most promising methods for processing all types of <200-µm coal feeds and tailings. Systems based on this technology are reviewed, and the results of investigations based on C900 Multi-Gravity Separator tests conducted to assess the treatment of <200-µm, extremely difficult-to-wash coal settling pond tailings are presented. Multi-Gravity Separator processing tests of ultra-fine tailings with a high clay particle size content (22.6% <10 µm and 60.1% <40 µm) and a 69.56% ash content show that this material can be effectively treated after desliming (<10 µm) of clay-size particles to produce a coal with a 20.6% ash at a separator combustible material recovery of 69.3%. Desliming is shown to be critical in reducing coal ash content and combustible material recovery. Similar improvements are anticipated in the recovery and separation pro-cesses for other enhanced gravity separation systems from the desliming of feeds. Although not a conventional form of treating Multi-Gravity Separator data, the existence of well-defined polynomial relationships based on the product of drum shake amplitude and shake frequency relative to product coal recovery, product ash content and yields at varying wash water flows is demonstrated. Low-amplitude and intermediate- to high-frequency bed agitation are shown to produce optimum ash reduction results.

Jan 1, 2007

By H. K. Lin

Cyclic voltammetric and potential step chronoam-perometric techniques were used to study gold dissolution in cyanide solution. Three distinct anodic and one cathodic peaks appear on the voltammogram between -0.50 and 0.80 V vs SCE. The corresponding reactions were proposed to explain the peaks and the passivations. The proposed reactions were in agreement with the effect of pH, cyanide concentration and the rotating speed of the electrode on the magnitude of the peak currents. Cyclic voltammetric tests, with various vertex potentials, were also conducted to examine the proposed reactions. Steady-state currents at various potentials were obtained by potential step chronoamperometric technique and were compared with transient currents obtained by the cyclic voltammetric technique.

Jan 1, 2000

By L. Martins

To increase zinc recovery in the concentrate, this investigation performed mineralogical characterization, dispersion studies, bench and pilot-scale flotation experiments and an industrial flotation trial. The objective was to verify the flotation behavior of the silicate zinc ore (calamine type) in the presence of slimes, with the aid of dispersing agents. Characterization studies identified the major minerals in the flotation feed as hemimorphite (calamine), quartz and dolomite. Dispersion tests showed that enhanced dispersion of the particles in the pulp in the absence of reagents occured at a pH range between 8.5 and 12.0. Bench-scale flotation experiments were planned using the statistical tool of complete factorial design at two levels, replicated once. These experiments showed, and were confirmed at the pilot-plant scale, that higher doses of sodium sulfide and polymeric dispersant combined with sodium silicate favored a higher metallurgical recovery. At 6,800 g/t (218 oz/st) sodium sulfide and 6,992 g/t (224 oz/st) polymeric dispersing agent combined with sodium silicate, a zinc grade of 38.4% in the final concentrate was achieved, at an average metallurgical recovery of 72.4%. The industrial trial confirmed the pilot scale results, leading to zinc recovery of 76.1% and a 37.3% zinc grade in the concentrate. Key words: Froth flotation; Flotation reagents; Flotation depressants; Zinc/ zinc ores

Jan 1, 2010

By Philip Weaver

The MIDAS project is funded by the European Commission (DG Research) and began on the 1st November 2013. The project will investigate the environmental impact of deep-sea mineral and energy extraction: specifically, polymetallic sulphides, manganese nodules, cobalt-rich ferromanganese crusts and the potential mining of rare earth elements. As deep-sea mining becomes ever closer, and the International Seabed Authority begins to develop its regulatory framework for exploitation of deep-sea minerals, MIDAS is well timed to provide fundamental scientific information. The MIDAS partnership represents a unique combination of scientists, industry, social scientists, legal experts, nongovernmental organisations and small and medium enterprises. MIDAS is carrying out research into the nature and scales of the potential impacts of mining including 1) physical disturbance of the seabed by mining, the creation of mine tailings; 2) the potential effects of particle-laden plumes in the water column, and 3) the possible toxic chemicals that might be released by the mining process. Key biological unknowns, such as connectivity between populations, impacts of the loss of biological diversity on ecosystem functioning, and how quickly the ecosystems will recover will all be addressed. The plan is to use this information to aid development of recommendations for best practice in the mining industry. A key component is the involvement of industry within the project and through stakeholder engagements to find feasible solutions. The project will work closely with European and international regulatory organisations to take these recommendations forward into legislation. A major element of MIDAS will be to develop methods and technologies for 1) preparing baseline assessments of biodiversity, and 2) monitoring activities remotely in the deep sea during and after exploitation, including ecosystem recovery. To carry out this work MIDAS is conducting a number of research cruises to examine the above issues at potential sites for exploitation of SMS and nodule deposits. This talk will present some of the recent findings of the project.

Sep 1, 2014

By Tim O’Neil

The earthmover tire shortage has been a case of bust and boom for the tire industry. Tire producers were unwilling to invest ahead of the mining boom. In their defense, though, the metals sector of the mining industry tends to be cyclic, tire manufacturers are not prescient. Until two years ago, low tire demand depressed prices. The incentive to invest in new, big-tire capacity was almost nonexistent, according to Prashant Prabhu, president of Michelin Earthmover Tire worldwide. “There has been very poor anticipation or a miscaluation of the amplitude of the (tire) demand on the part of just about everybody,” said Prabhu. What a turnaround. The earthmover tire market has grown by 30 percent over the past two years. Now there are not enough earth-mover tires and likely won’t be for the next two years. Goodyear said it was offering customers bias-ply tires when it could not supply enough radial-ply tires. Komatsu said it lost equipment sales because it could not provide the tires that customers requested. Volvo and Caterpillar said they are delivering some vehicles without tires, either promising tires later or leaving the customers – mine operators – to find their own rubber.

Jan 1, 2006

By James A. Pendleton

In response to Public Law 95-87 (SMCRA), Colorado promulgated regulations governing the mining of Coal. These regulations require the prediction, monitoring and mitigation of "material damage" caused by subsidence. All permitted underground coal mines within Colorado have approved subsidence programs. Preliminary monitoring results indicate the subsidence mechanical predictions have been sufficiently accurate to preclude material subsidence damage. The State of Colorado has developed a practical approach to regulating subsidence, which stresses monitoring verification of predicted subsidence phenomena. However, shortcomings exist in our ability to precisely predict the secondary consequences of subsidence, including effects to structures, the hydrologic balance and the environment. Lack of accuracy in predicting these secondary consequences results in uncertainty, necessitating conservatism in permitting. To avoid increasingly stringent permit restrictions, future research should emphasize the secondary consequences of subsidence.

Jan 1, 1986

By Michael Cruickshank

Bob Woolsey was born in 1936 in the state of Georgia and grew up to be a man of great integrity, vitality, wisdom and charm, totally neutral on matters of race, gender, and religion. A true Southern Gentleman in every sense of the word. His passing on July 9, 2008, the victim of an automobile collision, left an empty space in the hearts of his family, and his many friends and colleagues throughout the globe. The posthumous award of the Moore Medal of the International Marine Minerals Society, to Dr. J. Robert Woolsey for Excellence in the Development of Marine Minerals, is a well deserved tribute to this man who spent the last 30 years of his professional career heavily involved in research and development of marine minerals on an international basis. He first came to my attention in Burma in 1979 where, as a newly appointed technical advisor to the United Nations Development Program Offshore Exploration for Tin, I had to fill the shoes of an almost legendary figure "Dr. Bob", who accompanied by his wife Maxine had spent the previous two years initiating the program. Bob had planned to completion the construction in Singapore of a unique drilling vessel the RV Sea Drill, a spud anchored, twin-hulled barge, mounted with a Becker Drill, and designed for sampling alluvial tin deposits in the coastal waters of the Mergui Archipelago in the Andaman Sea, off Tenasserim. He had also designed and built, with the help of his side -kick Bruce Jernigan, a barge mounted dressing plant for reducing and concentrating the drill samples. The adventures of Dr. Bob in transporting the equipment to the drilling site in monsoon weather and the transfer of the drill barge from the Malaysian port of Ranong across the strait to Victoria Point in Burma with a mutinous crew will remain in the hearts and minds of his Burmese colleagues for many a long year. On his return to the States he joined, in 1980, the faculty of the University of Mississippi (UM) as assistant Professor of Geology and Geological Engineering. His prior experience in private industry and the United Nations had focused on marine mineral resources and related environmental engineering projects in Africa, South America, the Mediterranean, the South Pacific as well as south east Asia, working with dredges, mining for alluvial tin, gold, diamonds and industrial minerals. He continued to work in the area of marine minerals at UM, making a name for himself as Director of the Mississippi Mineral Resources Institute (MMRI).

Jan 1, 2008

According to the previous research, it is found that the thickness of cover is mostly less than 100 m for highwall mining system. However, for most of the Chinese surface coal mines, the mining depth is over 150 m; on the other hand, the shovel-truck is the most common mining technology. As a result, a lot of residual coal will be remained around end-walls. Considering these facts, the calculated methodology of highwall mining system under thick cover is presented in this paper. Meanwhile, numerical simulation of highwall mining system under thick cover was carried out. The outcome shows that the calculated methodology for pillar stability of highwall mining system under thick cover presented in this paper is acceptable. In other words, the highwall mining system is feasible to extract the residual coal around end-walls in Chinese surface coal mines. Thus, not only coal recovery ratio can be improved, but also can increase the production life of surface coal mines in China.

Jan 1, 2012

By Sam Ash

The Murray Mine was one of the first mechanized cut-and-fill underground gold operations in northern Nevada. At the end of 2002, mine production began to decline. So the mine entered a phase of remnant mining and began preparations to close down. The remaining mining took place along the ore waste boundary in previously condemned areas and in challenging ground conditions. To remain economically viable, new techniques were implemented in operations, geology, engineering and rock mechanics. These improvements pushed the edge of known and accepted mining practices and have allowed the Murray Mine to remain in operation.

Jan 1, 2006

By Keith E. Meyers

Condition monitoring is a viable troubleshooting practice among many industries to extend equipment performance, minimize unplanned downtime, reduce maintenance and repair time and costs, and increase related aspects of plant safety. But obstacles abound for mining, mineral-processing and cement operations striving to implement the technologies. Harsh machine environments can muddy efforts. High vibration in machinery can interfere with wide-spread rollout. Staff expertise or skills may be lacking. And costs may be prohibitive. Fault detection has emerged as a practical and cost-effective solution to identify process and machinery faults before failure interrupts productivity or jeopardizes worker safety. Fault detection can be a stand-alone system or connected to plant automation.

Jan 1, 2005

By J. Noll

Many underground metal/nonmetal mines are using enclosed cabs on mining equipment to reduce the exposure of miners to diesel particulate matter (DPM). However, some enclosed cab systems may not be meeting their expected efficiency in capturing DPM, which could be a result of inappropriate filter use, cab leaks, or insufficient pressurization. NIOSH investigated several types of filters for reducing DPM to determine which type had the best capture efficiency. The laboratory results indicated that a MERV 8 (Minimum Efficiency Reporting Value, as defined by the American Society of Heating, Refrigerating and Air- Conditioning Engineers) filter captured about 50 percent of the DPM, a MERV 16 filter collected 96-98 percent of the DPM, and two HEPA (high efficiency particulate air) grade filters captured over 99 percent of the DPM. NIOSH also performed a field study to measure the efficiency of two cabs at a limestone mine. The cab filtration systems of a loader and haul truck were found to be over 90 percent effective in removing DPM except under certain operating conditions when the efficiency was as low as 41 percent. Evidence seems to suggest that these conditions were when a window was open in the cab.

Jan 1, 2011