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By B. Holen, J. R. Baregi, J. A. Organiscak, A. B. Cecala

The National Institute for Occupational Safety and Health (NIOSH) cooperated with 3M Company in the design and testing of a new environmentally controlled primary crusher operator booth at the company’s Wausau granite quarry near Wausau, WI. This quarry had an older crusher booth without a central heating, ventilation and air conditioning (HVAC) system, and without an air filtration and pressurization system. A new replacement operator booth was designed and installed by 3M based on design considerations from past NIOSH research on enclosed cab filtration systems. NIOSH conducted pre-testing of the old booth and post-testing of the new booth to assess the new filtration and pressurization system’s effectiveness in controlling airborne dusts and particulates. The booth’s dust and particulate control effectiveness is described by its protection factor, expressed as a ratio of the outside to inside concentrations measured during testing. Results indicate that the old booth provided negligible airborne respirable dust protection and low particulate protection from the outside environment. The newly installed booth provided average respirable dust protection factors from 2 to 25 over five shifts of dust sampling with occasional worker ingress and egress from the booth, allowing some unfiltered contaminants to enter the enclosure. Shorter-term particle count testing outside and inside the booth under near-steady-state conditions, with no workers entering or exiting the booth, resulted in protection factors from 35 to 127 on 0.3- to 1.0-µm respirable size particulates under various HVAC airflow operating conditions.

Jan 1, 2015

By R. Benito

This paper describes the development of a life-of-mine schedule (LOM) for one of the world's largest known sedimentary copper-cobalt districts located in the Katanga Province, Democratic Republic of Congo (DRC). A particular feature of the Tenke Fungurume LOM schedule is the considerable number of pits/phases for scheduling, each competing to provide the best ore available to a capacity-constrained process facility. This paper discusses the LOM scheduling objectives and constraints, data preprocessing steps such as ore binning, block aggregation and clustering analysis as a scheduling aid, the mine scheduling approach and results and conclusions. Mining Engineering, 2011, Vol. 63, No. 8, pp. 39-47. Official publication of the Society for Mining, Metallurgy and Exploration, Inc.

Jan 1, 2011

By C. J. Bise, M. F. Sindelar

Regulations, such as the MINER Act of 2006, require the installation of redundant and secondary communication systems to assure that contact can be established with coal miners who may become trapped underground as a result of an event such as a fire, explosion or inundation. For half a century, the orientation towards underground communications has been that more complex systems better serve the coal miner. However, if a goal is to provide for an alternative means of establishing communication between the surface and trapped miners underground, then some of the technology employed should be simple, reliable and cost-effective. Coal mines spend hundreds of thousands of dollars on exploratory drillholes to characterize reserves, sometimes decades ahead of mine development. During the pre-mine planning phases, certain exploratory drillholes could be located and then outfitted with a simple communication link that would remain compatible with the continuing evolution of communication systems. Inexpensive links, whose locations would be accurately recorded, would be exposed by continuous miners during mine entry development, thereby allowing an underground phone to be connected to a surface station in the event of an emergency. A latent network of these communication links could be installed for less than $500 each, minimally affecting drilling and grouting operations, and could be designed to be compatible with many communication devices. This research examines methods and materials for incorporating an embedded communication link during pre-mine exploration drilling, addresses significant factors affecting its implementation, and presents a recommended design. Since mine plans are known to change, the objective is to minimize cost so that, if not used, the investment is minimal for a potential secondary means of communication between the surface and underground workings.

Jan 1, 2014

By Shangyong Lin, Wei Sun, Weiping Liu, Muhammad Azam, Junfeng Chen, Yujie Zhao, David Asubonteng, Michael Ngoie

Copper concentrates are widely used in smelting operations worldwide and typically consist of chalcopyrite ( CuFeS2) as the primary mineral, with chalcocite ( Cu2S) and bornite ( Cu5FeS4) as secondary copper-bearing minerals. However, these concentrates often contain hazardous impurities, such as the fluorine ion, which can result in various complications during the smelting process. These issues include equipment corrosion, gas treatment requirements, environmental hazards, and strained community relations. Furthermore, high fluorine content in copper concentrates can lead to penalties and limitations during sales. To address these challenges, this comprehensive review assesses current techniques for removing fluorine from copper concentrate. Drawing upon recent research and the findings in the field, the review analyzes the advantages and disadvantages of existing fluorine removal methods and identifies critical issues requiring attention in the future. This review provides valuable insights into the current state of fluorine removal from copper concentrates and serves as a practical guide for researchers and industry professionals in this field.

Aug 2, 2023

By Fei Chen, Xun Xu, Dezhong Kong, Yu Xiong

We address the problem of rib spalling caused by mining-induced roof movement. This problem affects production and safety of the working face. We address this problem by using the 3DEC numerical software to simulate the distribution and evolution regularity of displacement, stress, and the extent of plastic zone in the overlying strata and coal face during the advancing excavation of the 10,905 working face of the mine. Results showed that the first weighting interval of the 10,905 working face is 50 m, and the periodic weighting interval is 20 m. The fractures of overlying strata develop during the first weighting; the vertical stress and vertical displacement of the main roof increase by 45% and 10%, respectively; the vertical stress of the coal face increases by 11%; and the plastic zone in front of the working face increases rapidly. The displacement and stress of the main roof and coal face change periodically during the period of periodic weighting. The variation range during the periodic weighting is less than 30%, but the overall degree is larger than that before the first weighting. Finally, the integrity and rationality of numerical simulation are supplemented and verified by similarity simulation. On this basis, the proposed roof and coal face stability control scheme reduces the maximum horizontal displacement of the coal face from 16 to 4 cm, that is, a decrease of 75%. This study provides theoretical guidance for roof support and coal face stability control of working faces under similar conditions.

Dec 26, 2022

By Chee Theng

"Mineral processors know you can put in the best technology in the world but it won’t work optimally without the support of the operators. Conversely, you may have complete operator support but won’t get top results without the right technology. When the two come together, the returns can be phenomenal.The first day of talks at the 68th Annual Colorado MPD Conference, held April 26-28 at The Broadmoor in Colorado Springs, covered the ground on these industry wisdoms.Coming together as a team“Think of the people, not just the lab and the numbers. That makes all the difference,” said Dee Kippers, of FMI Henderson Mine, in her talk on “Process optimization during a market downturn (A Moly MacGyver story).” Kippers told an entertaining story of the journey she and her team took in tackling the issue of an annual spike in iron content in the product at Freeport- McMoRan’s Henderson primary molybdenum mine near Empire, CO.As the metallurgists tried one thing after another — cranking up the iron depressant, adjusting pH with sodium hydroxide and hydrated lime, modifying reagent levels — Kippers found that when she shared her results with the operators, communicated with them on what she was doing and got their input, they were more willing to work with her, and more understanding and supportive of her efforts.The results make the case for getting people on board and coming together as a team. The cost savings from their optimization efforts, with little capital investment, have been “enough to cover the annual salaries of our metallurgy department and then some,” Kippers said.Considering the environmentDavid Lemieux, of Dundee Sustainable Technologies (DST), talked next on “Cyanidefree process for gold extraction,” presenting the results obtained from a demonstration campaign of the company’s novel chlorination process for gold extraction and associated arsenic stabilization process. Developed at an investment cost of C$35 million, they are ready for commercialization, having been demonstrated on the laboratory, pilot and demonstration scales.The DST process is differentiated from the Plattner chlorination process, which was in use from 1851 to 1916, by moderate process conditions of atmospheric pressure and ambient temperature — the result of using sodium hypochlorite solution, or bleach, instead of direct injection of chlorine gas — and new, cheaper materials of construction, such as polymers, plastics, fiberreinforced plastics and Teflon, resulting in lower capital and operating expenditures."

Jan 7, 2018

By K. J. Bruxvoort

Background ground water quality is often used to drive remediation programs at sites with waters affected by mining activities. In the past these levels were sometimes chosen without rigorous statistical and geochemical analysis. A probability distribution approach was used at the Sweetwater Uranium Project to separate a large set of geochemical data into populations that represent contributions from different sources. Natural background populations were identified for major ions, metals, and radionuclides, and were submitted to the Nuclear Regulatory Commission to modify the extent of a Corrective Action Program and to establish control limits for future monitoring.

Jan 1, 1998

By Peter Riba

Up until ten years ago the industry had arrived at a relatively conventional, and consistent design of coke ovens. Through the years the designers and builders were not being heavily taxed to come up with revolutionary new designs. However, the stimulus for design change was ever present. These stimuli for change are quite important and they are the driving force which produce improvements. The most obvious stimulus to change a design is commercial. To "build a better mouse trap and the world will beat a path to your door" is the well used cliche which best befits this philosophy. As in all businesses, coke oven designs require that all of the considerations, which affect the cost or the desirability of the design, be optimized. One way to increase the desirability of the particular design, 1s to make the design in- expensive to operate. Or, put another way, to increase production for the same operating cost

Jan 1, 1980

By Helmut Mischo

For more than 100 years, diamond mining has been Namibia?s most important mining sector. Today, it provides the highest foreign currency income for the country?s development. Since the late 1970s, offshore mining of diamonds has gained more importance and now more than 60 percent of Namibia?s generally high-quality stones come from those offshore deposits, with a steady increase expected for the coming years. Diamonds in Namibia The mining industry is one of the three pillars of the Namibian economic development, along with tourism and fishing. Diamond mining is one of the two main mining activities in Namibia and diamond mining operations are rapidly moving from onshore to offshore deposits. This article provides a comprehensive overview of the current and future situation of the Namibian mining industry, with a special focus on the tasks and new technical developments for the successful excavation of beach and marine diamond deposits. The different deposits and the adequate applied mining technologies and methods are shown in examples.

Jan 1, 2011

By Yakup Cebeci, Leyla Kalender, Ceylan Yarluğkal Altınışık, Hikmet Sis

The abstract highlights the challenges in concentrating complex and non-sulfide lead-zinc ores and emphasizes the importance of froth flotation for their beneficiation. The study focuses on using process mineralogy to understand the flotation behavior of these ores from the Görgü region. The ore samples were characterized using various techniques, revealing oxidation and carbonation of primary minerals. The flotation results were interpreted in light of the mineralogical data, explaining the poor outcomes due to the complex nature of the ore, poor liberation, and lack of hydrophobicity.

Mar 22, 2022

By Danqing Gao, Brijes Mishra

Spatial variance of rock properties is an important characteristic of rock which addresses the heterogeneity of mechanical and physical properties and their effect on underground mining. Assessing spatial variance can be useful for both locating potential difficult grounds and performing reliability analysis in the mining support system. This study shows a microscale numerical model for rock material based on continuum mechanics. To consider the spatial correlation factor of mechanical properties in realistic rock mass, this study introduces a spatial correlation concept into the traditional type III extreme value distribution model. Based on the improved microscale random model, we conducted a series of numerical uniaxial compressive tests and one longwall mine model to investigate the progressive failure of rock. The results show that spatial correlation factor can significantly affect the load-deformation curves and fracture patterns. The spatial variance model was applied to a longwall mine that included several cutting sequences to observe the influence of the spatial variance on roof behavior. The cohesion and friction random fields induced failure that propagated randomly through the immediate roof in different entries. The results showed that the spatial variance provides an accurate prediction of erratic roof falls in coal mines.

Jul 20, 2020

By Sandeep Kumar Jeripotula, Govinda Raj Mandela, Aruna Manglapady

Dozer operators are frequently exposed to whole-body vibration (WBV) during the execution of their work. Occupational exposure to WBV in Indian surface coal mines was evaluated by measuring vibration intensity and duration of exposure. A triaxial accelerometer was placed on the operator seat surface for taking the readings. Based on frequency-weighted root mean square acceleration equivalent to 8-hr shift duration, i.e., (A(8)) all dozer operators have exceeded an Exposure Action Value (EAV) of 0.5 m/s2 , and 90% of dozers did not exceed Exposure Limit Value (ELV) of 1.15 m/s2 . Based on Vibration Dose Value (VDV (8)), all dozer operators have exceeded Exposure Limit Value (EAV) of 9.1 m/s1.75, but no dozer operators have exceeded Exposure Limit Value (ELV) of 21 m/s1.75. Further, an epidemiological study was performed for identifying the extent of musculoskeletal disorders (MSDs) among dozer operators. For the detailed study, 42 dozer operators and 22 controls were selected from 2 surface coal mines. The control group was not exposed to WBV. It was seen from the cross-sectional study that pain in the lower back was predominantly higher (83.33%) in the exposed group when compared with the control group (31.81%). Likewise, pain in the neck (47.61%), shoulder (42.85%), knees (42.85%), and ankle (11.90%) was higher in the exposed group than that of the control group (22.71%, 0%, 45.45%, and 4.54%). A significant observation among the exposed group was that there was degradation in the quality of life. The outcome of the study would assist in monitoring and mitigation of machinery-induced vibration diseases (MIVD) in India and generally applicable to most of the mechanized mines as well. However, comprehensive studies are still needed to enunciate the magnitude extent.

By I. Duckworth

P.T. Freeport Indonesia operates a mining complex located in the highlands of Papua, Indonesia. This district consists of underground and surface operations. The East Ertsberg skarn system (EESS) is one of the major orebodies in this district. Subsurface caving of the EESS has been carried out in a systematic series of mining lifts dating back almost 30 years. Present production from the third lift deep ore zone (DOZ), has reached 80 kt/d (88,000 stpd) during 2010, with this rate sustained through 2015. The orebody was proven below the existing caving level, with the next vertical block called the deep mill level zone (DMLZ).

Jan 1, 2010

By M. L. Harris, J. Organiscak, S. Klima, I. E. Perera

"The National Institute for Occupational Safety and Health (NIOSH) Pittsburgh Mining Research Division (PMRD) conducted underground evaluations in an attempt to quantify respirable rock dust generation when using an untreated rock dust and a rock dust treated with an anti-caking additive. Using PDM 3600s and 3700s, these evaluations measured respirable rock dust levels arising from a flinger-type application of rock dust on rib and roof surfaces. Rock dust with a majority of the respirable component removed was also applied in NIOSH’s Bruceton Experimental Mine (BEM) using a bantam duster. The respirable dust measurements obtained downwind from both of these tests are presented and discussed. This testing did not measure miners’ exposure to respirable coal mine dust under acceptable mining practices, but indicates the need for effective continuous administrative controls to be exercised when rock dusting to minimize the measured amount of rock dust in the sampling device. INTRODUCTION Two factors have combined to renew concern regarding respirable dust measurements and compliance. This renewed recognition is due to two regulations that have modified operators’ rock dust schedules. First, the 80% incombustible requirement in intake entries has increased both on-section and outby-the-section rock dusting. Secondly, the recent respirable dust regulation change that has increased the number of respirable dust samples taken per sampling cycle. Previously, when only 5 samples were needed bi-monthly, rock dusting could be scheduled to not interfere with the respirable dust sampling schedule. The significant number of samples now required under new regulations combined with the need to maintain 80% total incombustible content in active mining areas require the schedules for respirable dust sampling and rock dusting to intermix. This raises concerns about the amount of rock dust that potentially is included in the sampler weight gain. Additionally, the respirable dust maximum was lowered from 2.0 mg/m3 to 1.5 mg/m3 (effective August 1, 2016) increasing concern that rock dust contamination may be an issue. Currently, the acceptable practice is to apply administrative controls such as keeping the miners upwind during rock dust application or to schedule rock dusting during a maintenance shift when the number of miners present is lower. NIOSH’s research examining the quality of rock dust has led to the development of hydrophobic rock dusts."

Jan 1, 2017

By A. D. Hammond

Vanadium is a transition metal, ductile and silver-gray. It is harder than most metals and steels and it has a good resistance to corrosion. It is stable against alkalis and sulfuric and hydrochloric acids. Vanadium is oxidized in air at about 660° C (1,220° F), although an oxide layer forms even at room temperature. The chemistry of vanadium is noteworthy for the accessibility of the four adjacent oxidation states, 2-5. In aqueous solution, the colors are lilac V2+, green V3+, blue VO2+ and, at high pH, yellow VO42-. Considered to be as abundant as zinc, metallic vanadium is not found in nature, but it is known to exist in about 65 different minerals. Economically significant examples include patronite (VS4), vanadinite (Pb5(VO4)3Cl), associated to the uranium mineral carnotite (K2(UO2)2(VO4)2?3H2O) and in a vanadium mica called roscoelite K(V3+,Al,Mg)[(Si,Al)4O10] (OH)2. Other important vanadium ore oxides are montroseite (V,Fe)O(OH) and corvusite (Na,Ca,K)V8O2.4H2O. Much of the world?s vanadium mine production comes from magnetite-hosted deposits and, to a lesser extent, sedimentary-hosted sandstone.

Dec 1, 2013

By Frederic Chavan, Hans Jakob Windier, Shane Yanagisawa, Willy Ritz

The Zurichberg twin track tunnel is the main segment of the Swiss Federal Railway's new expressline. A heavy concrete lining with a circular cross-section was chosen to cope with the swelling tendency of the surrounding rock. The 4,356 m (14,300 ft) long, 11.52 m (38 ft) diameter tunnel was driven using a shielded Robbins TBM. A 1.20 m (4 ft) wide, 25 cm (10 in) thick precast lining was placed from within the shield tail as the excavation progressed. Tunnel excavation and initial lining operation were completed in 18 months, averaging 11.86 m/day (40 ft/day) in two nine hour shifts. After breaking through, the final 28 cm (11 in) thick concrete arch lining was cast in place.

Jan 1, 1989

By Blair K. Salisbury

Dissolution within Permian evaporites of the Delaware basin has created extreme lateral geologic and physical property inhomogeneity within and above the evaporites. Discriminating a sulfur deposit's geophysical signature from other variances is difficult. This is particularly true of porosity-dependent gravity and electrical methods. However, other techniques that detect alteration of strata above sulfur deposits may be applicable individually or in combination with other types of data. Relationships between sulfur deposits and gravity, magnetic, gamma radiation, spontaneous potential, and soil geochemical measurements are illustrated by data from several Delaware basin geophysical and geochemical surveys.

Jan 1, 1992

By Jack S. Watson, Rasika Nimkar, Robert M. Counce, BRADLEY BENNETT, Patrick Zhang

This study level process design represents an economically viable method for extracting thorium dioxide and other rare earth elements from monazite ore. This paper incorporates results from the 2019 capstone project from the honors Design Internship in Green Engineering in Chemical and Biomolecular Engineering. In this activity, senior students in Chemical Engineering at the University of Tennessee (UT) focused on the development and study of a process for the recovery of thorium dioxide and P2O5 from monazite. While not mandated, the process offers rare earth oxides as attractive byproducts. The project focused on recovery of byproducts rather than the creation or addition to waste streams. Additionally, (1) the process economics relied heavily on recovery of rare earth byproducts, (2) thoriumhandling portions of the process could be effectively segregated from rare earth and phosphate handling portions of the process, and (3) thorium and uranium content of waste streams should be carefully managed and eliminated where possible.

May 29, 2020

By Landy Stinnett

"When performing a valuation of a mineral property, a developing mine or perhaps an ongoing operation, the appraiser is typically provided with a range of information prepared by the property owner. This information can include ownership records, geological interpretation, assay data, an estimate of the reserves or resources believed to be on site (tons and grade), mine plans, production forecasts, capital and operating cost projections, and so forth.The appraiser familiarizes himself with the data, analyzes the various reports and then prepares the appraisal. There is usually a site visit, and there may be some effort at comparison of the particular mineral deposit with others in the region or with those of similar depositional characteristics, but for the most part, the appraiser is relying on the corporate documents, tempered by his/her experience in the field. Time is usually of the essence, the cost for the assignment has been trimmed, and therefore independent verification of the various components comprising the underlying data base (legal review, redrilling portions of the deposit, collection of new samples, re-assaying, etc.) is unlikely in most situations.In the case of high-value commodities — gold, silver, diamonds, perhaps the platinum-group elements — there have been numerous examples of the property owners attempting to increase the value of their holdings by nefarious methods. Most of these involve salting the deposit in some fashion; i.e., introducing small amounts of the commodity into samples being sent to a laboratory for analysis so that the resultant assay shows a higher grade (Donaldson, 2002; Greeley, 2001; Lechler et al., 2008 and Meech, 2001). Other schemes to enhance the apparent worth of a property include the use of nonstandard assay procedures, incorrect handling or withholding of the underlying information, and false reporting."

Sep 1, 2016

By Robert D. Saltsman

The inadequacy of our knowledge of the coal combustion process has long been recognized. This was expressed very well by Spicer and Finney (1). "The control of combustion processes in industry and the design of the equipment necessary for efficient burning to take place have always been very much branches of an industrial art rather than of an exact science. This has been especially true of the utilization of coal, a substance so hetrogeneous and complex in character that all too little is known about its chemical and physical composition.' During the past several years one branch of coal utilization, that of high temperature carbonization; has made significant advances from being an art into being an exact science. This has been accomplished by the development of petrographic techniques for identifying, measuring, and determining the thermal properties of the organic materials which affect the carbonization of coal and the correlation of this information with a pre-existing standard of coke quality, the stability index.

Jan 1, 1964