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By R. J. Nankee

Coal is our most abundant, low cost energy resource. Expansion of its use is being challenged due to "SO2 emission" regulation with even more restrictive legislation pending. High quality coal reserves are becoming more limited due to greater use in recent years. Aids to allow more use of coal in today's environment include beneficiation of coal before combustion and scrubbing the emissions from coal during combustion. Dow's efforts to help meet these challenges by beneficiating coal include true heavy media gravity separations with chlorinated solvents and liquid/liquid partitioning processes and "Dow Solvent Recovery Technology" to recover the solvent from product (or floats) and rejects (sinks), The objectives of the efforts to clean coal are to reduce sulfur and ash. In this paper, the solvents will be described; a general flow diagram presented; some of the results on upgrading various coals will be described, and projected costs of full-scale plants using chlorinated solvents will be compared to conventional cleaning plants.

Jan 1, 1985

By R. Klimpel

Recent work has shown that the measurement of flotation kinetics in the laboratory is useful in providing guidelines on how operating sulfide flotation plant performance can be improved. This work outlines the influence of various factors on flotation kinetics such as collector/frother type and concentration, particle size, and frother blending.

Jan 1, 1981

By F. Heivilin

If the past is the key to the future, we will have ?tough? times maintaining Industrial Mineral reserves we have and proving new reserves around our plants and in new locations. The tough times will come from resources being more difficult to find, more hoops to go thru to make them Proven or Probable reserves. As always, Industrial Minerals require competitive quality, location, and costs. Since in most cases the market has suppliers, you will have to take away customers from their present supplier. This may take years or not happen even with lower cost higher quality raw materials. To determine the finished cost for a new deposit you need to design, determine capital costs, and operating costs for a new plant . Stripping, mining, hauling, processing, and transportation costs are part of the equation. After satisfying that your costs are in line you will need to do production tests to make sure the process works on the ore. You may want to complete permitting before purchasing the property. If you are new in the business you will have to prove you can deliver the right quality, the right quantity, on time consistently year after year at lower cost to take away a customer. Without being in the market this will be hard. The cut off grades to enter a market may be much lower than sale indicates because a competitor often lowers the price to keep you out of the market. We have many more items to check before the new deposits can be put on reserves. Our old reserves will require drilling to check for new products and prove that they do not contain items that would make them unusable for our product line or cause permitting problems. Archeological checks, wetlands, more water discharge testing, county zoning, and endangered species are among many items that have been added to mine permits. There will be more. A 4-6 page mining permit becomes 30-300 pages and consists of 5-15 permits, any of which might be a fatal stumbling block. It is not guaranteed that we can mine what we have on reserves. We may fight and lose. Oil-Dri?s loss in Reno and LaPort?s in England are examples where permitting failed. The NOx, sulfur, and carbon problems are just starting. Dioxin is in the background requiring monitoring on food products to Europe. What other anions, cations, endangered species, and land types are going to be problems in the future are guesses now. What new products are we going to have to test for and cause out of balance reserves? If there are none we probably won?t be here. We are competing for land use with ?Endangered Species?, wetlands, farming, forestry, cities, roads, and hunting. We?ve mined the best quality, low overburden, easiest to mine and process raw materials. The price of land and taxes are increasing. Old royalties are 2-3 times the present acre value instead of 8-10 times the property value when leased. Land taxes are up. It was and is best that we get the land in Fee Simple Title. This isn?t always possible. However, plants are closing and people have overlooked, made mistakes in drilling or interpretation of deposits. These may be opportunities. China is eating up high quality ?Industrial Minerals ?which have caused prices to rise. We may need to change our cutoffs? in terms of smaller pit sizes and higher overburden ratios. This is money in the bank. Overburden ratios and other items increasing cutoff costs need to be rethought. Suddenly doubling cutoff ratios for overburden and decreasing pit sizes are good alternatives to looking elsewhere where we might not be able to mine for a number of reasons. The higher prices make them competitive, especially when a competitor goes out of business. However, our low overburden ratios and short hauls around our plants are not safe from new roads, condemnation by county or city governments (N. J.), zoning changes (Reno, FL., CA, and environmental regulation changes (Buffers GA, MS). New roads ?Interstates? can take reserves, increase hauling distances and reduce tons per load. Let?s combine the Refractories, fullers earth, and bentonite industries and use the last 40 years as a guide to the future looking for problems and opportunities. Some or most of the following will apply to other minerals. WHERE DO WE LOOK? First, on our own properties, those next to our properties and on properties near our competitor?s plants. Where the profit margin has increased, the distance from the plant and thickness of overburden we can use is increased. The thickness of clay is decreased. For new locations we pick the ideal location and look at deposits and closed or open operations in ever increasing distances away from that location. We need to be aware of: 1. Increased transportation costs a. Access to Roads -Backhauls b. Haul with doubles and triples c. Railroads - Loading on sidings - Ability to get switches - Cars/backhauls versus rates 2. Cost of building a new plant 3. Cost of infrastructure 4. Cost of repair or new equipment when purchasing an operating or shutdown plant. 5. Local, state, and federal mine and environmental permitting. When exploring around an established operation expect that property acquisition, drilling, mining, stripping, and hauling costs will be greater due to them having second, third, or even fourth the pick of the deposits. I found this in New Jersey looking for refractories and around Quincy, Florida looking for attapulgite. You may be able to get some better properties because the operating company has angered some land owners, their drillers missed the clay, or the property wasn?t available when they were actively exploring for reserves. You may have some product lines your

Jan 1, 2009

By Shahab Alizadeh, Ahmad Khodadadi Darban, Mehdi Mohseni, Mahmoud Abdollahy

This study probed the selective separation of lanthanum and yttrium in a nitrate medium in the presence of aluminum and calcium impurities using di-(2-ethylhexyl) phosphoric acid (D2EHPA). The factors studied in a central composite design (CCD) included extractant concentration, pH, concentration ratio of total impurities to rare earth elements, and interaction of these three factors. The extraction mechanism and types of extracted metal-containing species were delineated by the slope analysis method. The obtained thermodynamic data showed that lanthanum and yttrium extraction by the D2EHPA extractant was exothermic. The extraction of both rare earth elements was accompanied by an entropy reduction. The negative magnitude of ΔS in yttrium extraction reaction suggests stronger D2EHPA-Y(III) complexation relative to La(III). As entropy decreased and enthalpy increased, the extraction process became unspontaneous. Using the proposed flowsheet, lanthanum and yttrium products with > 90% purity were obtained.

Aug 10, 2021

By H. Dreissen

Upgrading of low-concentration ores is of growing importance today. The Heavy Medium Cyclone Process, thanks to strong centrifugal forces, effectively separates particles varying only slightly in specific gravity but widely in size. The paper discusses the separation efficiency, the method of assessing that efficiency, and the influence of such factors as medium solids. The operating results of nine heavy medium cyclone plants handling following minerals are reported: barite, wolfram, iron, magnesite, diamond, lead-zinc, fluorspar, rocksalt potash. Highlighted are an improved recovery system for heavy medium and some other developments, such as techniques for separation down to 0.1mm and the application in the field of recycling.

Jan 1, 1980

By R. L. Loofbourow

Reasons for reexamining underground mining include: 1. The assurance that more deep deposits of useful minerals will be found. 2. The existence of deeply covered deposits of industrial minerals near large markets where quarries are becoming depleted or are lacking. 3. Surface property values, zoning and other limitations on open pit mining. 4. Expectation that underground space will be increasingly used for transportation, power plants, storage and similar purposes. 5. The improvements which have been made in underground mining. During the last three or four decades many changes and improvements have been made underground. All underground construction and mining has benefitted to some extent but the effect on the productivity of labor employed with some methods- has changed little and the use of these methods has declined. Productivity of labor in other methods has increased substantially. The relative usefulness of mining methods has changed and a vital industry, bituminous coal, has been returned to health. In this paper, consideration is limited to nine methods used with high productivity during the period under review. These methods are not necessarily better than others but they may be considered the prime methods in the sense that, in our economy, many, low grade ores, coal and the principal industrial minerals could hardly be produced by less productive means.2 Although most of the examples cited are from mining as such., the first four methods discussed can be used for the construction of stable excavations of various' shapes in sound rock.

Jan 1, 1967

By M. A. Giralico

A new generation of hydraulic efficient pumper and auxiliary impeller designs is the result of an extensive research program focused on improving the overall performance of optimized SX/EW plants. Combined with the proper scale-up, these optimized designs will greatly reduce aqueous and organic entrainment losses, reduce or eliminate air entrainment and crud formation, enhance mass-transfer and maximize the overall copper yield. Currently, these new pumper and auxiliary impellers are installed full-scale in numerous plants ranging in flow rates from 90 to 15000 G.P.M. and developed heads up to 51 inches. Operational results reported by the independent metallurgist at each processing plant are reporting the lowest entrainment results in the industry. Further R&D has just been completed on a new mixing configuration that separates the systems mixing and pumping requirements. Results from the system pilot test document further improvements in reduction of both chemical entrainment and crud formation, while keeping mass transfer stage efficiencies.

Jan 1, 1998

By Immo H. Redeker

Introduction In October of 1961 Texas Gulf Sulphur Company contacted the Asheville Minerals Research Laboratory, of the North Carolina State University, and requested assistance in the development of a phosphate ore body in Beaufort County. The main: objectives of the work at Asheville were defined as follows. The Laboratory should try to determine on the basis of drill core samples, submitted by Texas Gulf Sulphur Company, the highest grade of phosphate concentrate that could be obtained with high recoveries from North Carolina ore, the thickness of the ore body that could be treated economically in one section, and the quantity of concentrate that could be obtained per acre. The results should be compared with data obtained from the treatment of Florida ores. It was important to use mineral preparation methods during the initial laboratory work that could be verified later by continuous pilot plant operation and could be scaled-up for a commercial plant. The writer was in charge of the project at the Asheville Minerals Research Laboratory and participated in the development of one of North Carolina's greatest mineral resources from the first drill core examination to the production of the first poundage and tonnage quantities of flotation concentrates. The Lee Creek phosphate mine and mill was put in operation in early 1966 and can produce three million tons of phosphate concentrate a year. Sulfuric- acid, and phosphoric acid plant, diamonium phosphate plant and triple super phosphate plants came on stream in 1967; at that time they were the world's largest. Now that a phosphate industry has been established in the State, it]

Jan 1, 1971

By F. N. Kissell

U.A. Mine Safety and Health Administration (MSHA) coal dust compliance data sometimes shows high silica levels at roof bolters. However, it is unclear whether this silica normally originates from the bolter itself or from other dust sources upwind of the bolter research studies to answer this question at individual mines have been conducted. However, operational practices vary from mine to mine thus, the information gleaned from any one study cannot be accurately extrapolated to describe silica dust sources in most mines. In this paper, three decades of bolter dust research are reviewed the results showed that, while inadequate maintenance on the bolter dust collection system can result in excessive dust, more likely reasons for high silica levels are inadequate ventilation of the mine entries being bolted and dust traveling downwind from the continuous miner to the bolter. Scrubbers on continuous miners may not be removing as much silica dust as expected. Mining Engineering, 2011, Vol. 63, No. 10, pp. 78-82. Official publication of the Society for Mining, Metallurgy and exploration, Inc.

Jan 1, 2011

By A. K. Martin

Adaptive management can be described as a structured, iterative process of robust decision making in the face of uncertainty, with a goal of reducing uncertainty over time through system monitoring. Adaptive management is a tool which can be applied to not only change a system, but learn about the system (Holling, 1978). Adaptive management has been used in ecosystem management for years and guidance is provided in a variety of handbooks and publications. Adaptive management can be applied to industrial facilities and mines through the use of an adaptive environmental management plan (AEMP) and associated practices. The goal of this paper is to provide an explanation of how the plans and practices support regulatory agency approvals and permitting, span the life-cycle of mines, manage uncertainty, and assist in addressing mining impact and legacy issues. AEMPs and associated practices are useful tools to address the uncertainties in identifying, evaluating, and managing impacts of proposed new and modified mining facilities undergoing environmental review. Once a proposed project is approved, the AEMP continues as a living document, being informed, revised, and adapted by the operations. The AEMP can serve as an ongoing management tool for describing and evaluating environmental impacts, continuing in operations into post reclamation. If initiated during planning and environmental review of a project (and in some locations such as the United States [U.S.], the preparation of an Environmental Impact Statement (EIS)), the AEMP becomes a basis to identify, monitor, and manage potential project environmental impacts. Development of an AEMP for an operating mine is also beneficial since there are generally developing and ongoing environmental issues at those facilities as well. Over time, the AEMP is adapted to changing requirements and conditions including those anticipated and unanticipated. Ever increasing scrutiny of mining projects and the complexities of the EIS process highlight the uncertainties inherent in impact predictions. In making the momentous decision of initial project approval, these uncertainties can discourage the regulatory agencies? actions and create stakeholder anxiety and controversy about a project. A well-designed AEMP can support the decision to approve an EIS and enable a project to move forward. Additionally, an AEMP can inform financial assurance estimates and revisions over the life of a mine providing all parties including the citizens of the surrounding communities with greater confidence that potential environmental impacts and risks will be well managed.

Feb 23, 2014

By Nikhil Dhawan, Veeranjaneyulu Rayapudi

This study investigates upgrading of low-grade banded hematite quartzite iron ore (Fe ~31%). Conventional beneficiation was found to be futile. The susceptibility of iron phases to microwave exposure and their selective absorption assists in the liberation of iron values. Microwave exposure of coarse particles at 540 W for 10 min yielded a concentrate with Fe 56.30% and recovery of 50.68%. Conventional carbothermic reduction at 500 °C, 60 min and 9% charcoal yielded a concentrate with Fe 57.6% and iron recovery of 68%. The presence of sufficiently bonded silica leads to an easy formation of a fayalite phase. The microwave reduction design yielded FeG of 57.6%, FeR of 47% and a yield of 24% at an optimal condition of 540 W, 8 min and 6% charcoal. It was found that a small fraction of microwave-irradiated ore-charcoal mixture melted rapidly, and pure ferrite balls were observed within 8 min. An optical micrograph of a ferrite ball reveals the retained austenite and martensite phase.

By Matthew Holden, Jason Emery, Matthew Benjamin, Peter Craig

Over the last 25 years, through adversity and a growing level of risk mitigation, Australian Longwall mines have been using higher and higher capacity cable bolts for secondary support. A recent survey revealed 85% of Australian longwall cable bolts are a 70 tonne capacity pre-tensioned hollow post groutable system. Mines avoiding pumping cementitious grouts are sometimes using pre-tensioned resin encapsulated solid cable bolts of over 90 tonne capacity. Results from various industry and University research has led to manufacturer's fine tuning the construction of their cable bolts. A review of this research explains how smooth wire construction is now dominant. Aggressive shear has also led to some mines using 8 tonnes pre-tension instead of the previous common 20 tonnes pre-tension. Lower pre-tension acceptance is now leading to a greater use of threaded cable bolt end fittings, these are tensioned to 8 tonne using the drill motor torque. A recent development is the TEX cable bolt, a slim line threaded end fitting that fits with the drill hole like a standard rock bolt. This cable is being installed at the coal face as primary support off bolter-miners. The laboratory and in-situ testing of the TEX cable is presented. In a bid to improve gateroad development rates and ground support in the last several years, a 100 tonne tensile capacity Goliath cable system was developed. The latest development in resin anchored solid cables is a 110 tonne capacity cable bolt, with laboratory and in-situ testing results presented.

Jun 25, 2024

By A. Hajati

The main purpose of this study was to find the optimum values for factors affecting the Zn recovery rate using oxine or dithizone as a chelating agent collector during flotation in a Hallimond tube. Eight control factors, including four levels of pH, oxine/dithizone, corn starch, sodium thiosulfate, sodium citrate, sodium silicate, conditioning and floating durations were considered in a Taguchi experimental design technique. An L32 orthogonal array was applied to determine the signal-to-noise (S/N) ratio. Analysis of variance (ANOVA) was used to determine the optimum conditions and the most significant parameters affecting the reaction rate. Analysis of the experiments using the Taguchi approach indicated that pH had the highest contribution to the recovery rate of zinc oxide particles. The results showed that the recovery rate of zinc increased by 43.4 ± 3.0% and 24.9 ± 3.2% using oxine and dithizone, respectively, under optimum conditions with a confidence level of 90%.

Jan 1, 2010

By Taekhee Lee, Steven Mischler, Shawn Vanderslice

Diesel-powered equipment is widely used in the underground mining industry and their popularity results from properties including efficiency, versatility, reliability, and durability. In the U.S. approximately 7,700 diesel engines were used in 177 underground metal and nonmetal mines as of 2005 [MSHA 2005], and these numbers have likely increased since that time. Diesel engines have been shown to be a major contributor to submicron carbonaceous, respirable, and total particulate mass in the air of underground metal mines [Zielinska et al. 2002, McDonald et al. 2003], and their extensive use results in approximately 13,000 underground metal/nonmetal (M/NM) miners (MSHA 2005) in the U.S. being potentially exposed to aerosols and gases emitted by diesel engines (MSHA 2001, MSHA 2006). Exposure to diesel exhaust has been linked to adverse health outcomes including cancer, cardiovascular, and respiratory diseases (Attfield et al. 2012, Silverman et al. 2012), and in 2012 diesel exhaust was categorized by the International Agency for Research on Cancer (IARC) as a Group 1 human carcinogen (IARC 2012). Exposure to diesel particulate matter (DPM) is especially concerning for underground miners since underground mine environments have been shown to have some of the highest levels of diesel exhaust in the U.S. (EPA 2002, MSHA 2001, MSHA 2006, Pronk et al. 2009). Due to the potential for elevated DPM concentrations in mines, the Mine Safety and Health Administration (MSHA) promulgated a rule to limit exposures of metal/ nonmetal underground miners to DPM to an eight-hour time-weighted average (TWA) of 160 μg/m3 total carbon (TC) (MSHA 2001, MSHA 2006, MSHA 2008). Since this rule went into effect, DPM exposures have been reduced, but are still elevated when compared to other occupations (Pronk et al. 2009, Noll et al. 2015). MSHA compliance data between 2005 to the present show that underground blasters represent 21% of all DPM overexposures in M/NM mines and are one of the highest exposed professions in mining often resulting from low ventilation in the area where blasters are working. Because mines have difficulty controlling DPM in these low ventilation areas, additional control technologies may be needed to reduce exposures. Administrative controls, where miners work on off schedules or upstream of diesel vehicles to avoid the exposures to DPM (Noll et al. 2015) is one possibility, but these types of solutions are not always feasible or practical. A canopy air curtain is another potential control technology to help reduce exposures of blasters to DPM. Listak and Beck (2012) showed that this control technology reduced respirable dust concentration under a roof bolter’s canopy by 67%–75% and recommended air velocities greater than 0.5 m/s for dust reductions of greater than 50%. Additional work showed that a canopy air curtain could be designed for a shuttle car, and some initial testing by the National Institute for Occupational Safety and Health (NIOSH) showed reductions of respirable mine dust between 66% to 70%. As seen in Figure 1, the canopy air curtain delivers clean air over the operator’s breathing zone. A fan draws in air through a filter to capture the dust and then supplies clean air beneath the canopy where a miner is working. The use of the canopy air curtain to reduce exposures to diesel particulate matter was first discussed by Noll et al. (2020). In this study the diesel canopy air curtain (DCAC) reduced the DPM concentrations under the canopy by up to 90%. For this research the DCAC was designed to attach to the basket cover of an ammonium nitrate fuel oil ( ANFO) loader (Figure 2) and provide clean air blowing over the miners as they work in the basket. The initial tests used clean air drawn from the mine’s intake and did not try to filter the DPM from the air. Filtering DPM has extra challenges when compared to filtering mine dust particles. The particles of DPM are smaller (submicron and nanometer) than dust particles (greater than 1 micron); therefore, the filtration system must be adjusted to capture submicron particles. A MERV 13 filter was used in previous canopy air curtain research on mine dust control, but this filter is only designed to capture 50%–75% of submicron particles, and this capture efficiency is too low for removing DPM, so a higher efficiency filter is needed. Higher efficiency filters increase the pressure across the filter media which results in decreased airflow or leaks around the filter and reduces the effectiveness of the control for protecting miners from DPM. The optimal filter needs to capture DPM particles at a high efficiency while still allowing the needed airflows to prevent contaminated air from entering the miner’s breathing zone. Listak and Beck (2012) recommended velocities greater than 0.5 m/s for dust reductions of greater than 50%. However, airflows too high have been shown to reduce miners’ thermal comfort; Roghanchi et al. (2016) suggest the optimal velocity for thermal comfort is between 1–2 m/s. Thus, airflow over the miner should be limited to the range of 0.5 to 2.0 m/s. This current study presents the results from research evaluating the reduction of DPM concentrations, under the DCAC, when using a higher efficiency filter (MERV 16) to remove DPM from the DCAC airstream.

Feb 1, 2024

By K. K. Kohli

Since the adoption of the Surface Mining Reclamation and Control Act of 1977, which mandates that surface subsidence be an intergral part of the underground coal mine design, there has been a sudden rise of demand on guidelines for minimizing surface subsidence and its associated structural damages. Unfortunately there is no sufficient amount of systematic subsidence data to fill such a gap, although considerable research has been devoted to the subsidence-induced damages of surface structures in the past. However, it was said that many surface subsidence surveys have been performed and monitored by coal companies during the past twenty years, and that it will be a great source of information for subsidence engineering design if they can be collected and assembled together. An effort was therefore initiated in the Department of Mining Engineering, West Virginia University, under contract with the U. S. Bureau of Mines in December 1978 to contact each individual coal company in the Northern Appalachian Coal Field for any surface subsidence survey data. After 10 months' survey, the data collected include 17 longwall panels and 2 room and pillar sections. The data in-each panel and section cover the complete set of subsidence survey raw data, underground mine layout maps, surface topo maps, geological loggings showing the stratigraphic sequences and thickness of the overburden, and if available, locations and types of surface structures. On-site visits were followed to study the surface terraines and structures. Interviews were conducted with the owners of the surface structures in most cases about, if any, the history and characteristics of damages.

Jan 1, 1980

By J. Miller, B. Slaker, M. M. Sears, G. Rashed

Ground falls represent a significant hazard at underground mines in the stone, sand, and gravel (SSG) sector in the USA. Researchers from the National Institute for Occupational Safety and Health (NIOSH) are currently conducting detailed investigations into the complex loading conditions at underground stone mines operating in challenging conditions. This paper presents the application of numerical modeling to analyze pillar and roof stability at a dipping underground limestone mine. A validated numerical model was used to explore the potential behavior of the pillars and roof as loading conditions change. The validated model was used to compare changes in mining sequence, overburden depth, and the in situ stress field. This will allow mine operators and engineers to have a better idea of the conditions that could be encountered as mining progresses. Results from the numerical modeling indicate that roof displacement more than doubles as the vertical stress increases from 10 MPa (1450 psi) to 19 MPa (2750 psi) when the maximum and minimum horizontal stresses were 41 MPa (5950 psi) and 22 MPa (3190 psi), respectively. Consequently, as the pillar load increases, the safety factor of the pillars is projected to decrease by about 25%. The impact of the practical application of numerical models can result in a reduction of ground-fall accidents and injuries as well as generally safer working conditions.

Feb 2, 2021

By Oliver W. Marsden, John O. Marsden

This paper presents the results of a hypothetical case study that evaluates the potential transition of a large copper mining and extraction operation to 90% renewable energy. The case study considers three phases to accomplish such a transition; phase I considers installation of renewable power generation at the site to meet a portion of the current electric power needs, phase II considers conversion of diesel combustion mining equipment to electric equipment, and phase III considers implementation of renewable energy generation coupled with energy storage systems to provide approximately 90% of the total mine site energy requirements. The paper evaluates the results in the context of a range of purchased electric power unit costs ($0.065, $0.100, and $0.135/kWh) as well as various carbon tax scenarios ($0, $5.00, and $37.30/t CO2). While the case study is hypothetical and considers a range of assumptions, it clearly identifies a pathway to potentially economically viable transitions to a renewable energy platform for mining companies. This represents an approach that mining companies can use to help to meet emissions targets, as well as social responsibility and reporting requirements.

Jun 4, 2021

By Z. Hyder, A. Urquidez

"INTRODUCTION The Waste Isolation Pilot Plant (WIPP) is located approximately 26 miles southeast of Carlsbad, New Mexico and is the nation’s first underground geologic repository for transuranic (TRU) and TRU-mixed waste (see Figure 1). The WIPP facility was opened for operation in 1999 when the first TRU waste shipment arrived at the WIPP facility for disposal.WIPP facility does not employ typical production aspects of a conventional mine. Instead, the mining focus is on the quality of the excavation to ensure safe disposal of TRU and TRU-mixed waste (Walls, 1991). GEOLOGY WIPP underground repository is mined within a 2,000 feet-thick bedded-halite formation (Salado Formation) (see Figure 2). The WIPP underground repository is located approximately 2,150 feet beneath the surface near the center of the Salado Formation. Geologic criterion and site-selection factors evaluated for the selection of the repository included topography, depth, thickness, lateral extent, lithology, stratigraphy, structure, erosion, dissolution, subsidence, surface water, aquifers, hydrologic transport, climatic fluctuations, manmade penetrations (U.S. Department of Energy, 1980).FACILITY DESIGN Profit did not play a major role in the WIPP’s conception like in a conventional mine. This was due to the extensive amount of additional regulations and safety controls that had to be built into the WIPP facility. Since it is nuclear and hazardous waste disposal facility, it must meet certain federal and state requirements for TRU-mixed waste. One of the major regulatory drivers for the WIPP facility is defined in the WIPP Land Withdrawal Act (LWA). One of the requirements in the WIPP LWA requires the DOE to submit documentation of continued compliance with Title 40 CFR Part 191, Subparts B, and C. These standards are regulated by the Environmental Protection Agency (EPA). The DOE must submit documentation of continued compliance (recertification) with these regulations every five years. In addition to the LWA, the Resource Conservation and Recovery Act (RCRA) is another major regulatory driver for the WIPP facility. Since the WIPP facility is categorized as a “Miscellaneous Unit” under 40 CFR, it must meet extensive environmental performance standards. These standards are defined in the WIPP Hazardous Waste Facility Permit (HWFP). The HWFP defines the terms and conditions that the Secretary of the New Mexico Environment Department has determined necessary to protect human health and the environment (U.S. Department of Energy and Nuclear Waste Partnership LLC, 2015)."

Jan 1, 2017

By Zhonglin Ye, Guangping Dai, Ba Zhang, Yonggang Wei, Shiwei Zhou, Bo Li, Hua Wang

Decreasing copper content in slag is critical for improving copper recovery, where apparent viscosity is the main factor affecting the separation of matte/copper from the slag. The viscous behavior of copper converter slag was investigated during reduction process in this paper, and its non-Newtonian viscous behavior and shear thickening characteristics were clarified. The effects of silicate structure and solid particles in the melt on the slag apparent viscosity were investigated. As slag cleaning proceeded in an electric furnace, the magnetite gradually transformed into ferrous oxide, increasing the FeO/SiO2 ratio. With this ratio increased from 1.2 to 2.0, the slag structure was simplified, and its apparent viscosity decreased from 0.26 to 0.12 Pa·s at 1523 K. The iron phase was excessively reduced to metallic state; the slag contained metallic copper-iron alloy particles, increasing apparent viscosity. The apparent viscosity and phase structure of the slag corresponding to the iron phase reduction process were analyzed in detail; the results obtained in the present study are of great significance to the reasonable control of the converter copper slag cleaning process.

Nov 7, 2022

By Del Brock, Dan Wooton

The design/build of two adjacent vertical mine shafts in difficult ground conditions at a mining complex in the midwestern United States required innovative construction techniques. Construction of the 267-m-deep Service Shaft required full depth dewatering wells and ground freezing. Blind drilling was utilized to excavate the 257-m-deep Production Shaft and it was finished with a steel/concrete composite liner that was floated into place. An equally unique component of the installation included supplying a high capacity vertical conveyor system, featuring a 273-m-lift. Other components of the project include the mine level development, as well as the design and installation of three hoisting systems, including a 45-ton capacity men/materials hoisting system.

Jan 1, 2003