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By E. B. McNew, J. M. Barnes, A. E. Torma

The applicability of biosorbent materials for the removal of uranium and other heavy metals from synthetic and actual uranium mil 1 tailing (UMT) solutions has been investigated. The biosorbent materials used in this study were barium loaded beads of alginate, alginate-dextran sulfate, alginate-carrageenan, and alginate-xanthan gum. These studies were performed in stirred vessels and packed columns. It was observed that 100 percent of the uranium could be removed from a synthetic solution following 2 hours of contact time in a stirred vessel, and 80-100% of U, V, Mo, Mn, Sr, and Zn could be removed from a UMT effluent solution with a packed column. Kinetic evaluations were performed, using a generalized rate equation, on the biosorption of uranium with these barium loaded beads.

Jan 1, 1992

By Paul H. Miller

After passage by the Congress, Public Law 95-87, the "Surface Mining Control and Reclamation Act of 1977" was signed by President Carter on August 3, 1977. This law, in its simplest form, was intended to control the environmental effects of surface coal mining and to ensure that mined land is restored to a condition equivalent to that prior to mining. Immediately after the signing, the wheels of government bureaucracy began turning to establish a new federal agency -the Office of Surface Mining Reclamation and Enforcement or OSM -in the Interior Department that would implement the provisions of the Act. Since this took time and because the Congress had not yet provided funding for OSM, a special task force was assembled within the Interior Department to begin the task of writing interim regulations to implement the Act. With respect to the use of explosives, the Act specified that a blasting plan be included in the application for a mining permit. The blasting plan will outline the procedures an operator will use to meet specified environmental protection performance standards. The performance standards established by the Act require explosives to be used only in accordance with existing state and federal laws and regulations and with regulations to be promulgated by the regulatory authority. The regulatory authority was defined as either a state agency operating under an approved state program or the OSM operating under a federal program. As a minimum, it was specified that the regulations should include provisions to require that: 1) a blasting schedule be published in a local newspaper and be mailed to local governments and to all residents living within 1/2 mile of the blasting site . 2) daily notice be given to residents in the area prior to blasting. 3) blast reports be prepared that are maintained for three years and available on request to the public. 4) blasts be designed to prevent injury to persons, damage to property outside the permit area, adverse impacts on underground mines and adverse effects on ground or surface water channels or availability outside the permit area. 5) upon request of residents or property owners within 1/2 mile of the permit area, preblast surveys shall

Jan 1, 1978

By G. E. Wasson

Consolidation Coal Co. tested the agglomeration of fine coal using a laboratory pellet mill. The principal operating variables examined were feed coal moisture, coal size distribution, and additives to the feed coal. The moisture of the feed coal was found to be critical to both the pellet mill operability and the product strength. Coals, with feed moistures too high to pelletize, could be pelletized if mixed with lime or a water absorbent material. The addition of dry starch binder improved the product strength.

Jan 1, 1991

By W. J. McDonough

Rapid growth and acceptance of engineered materials have changed the way we live. We have come to expect improved performance at less cost. At the same time, our awareness of societal and environmental issues created by these materials during and after their lifetime has been heightened. As a result, material lifecycle analysis is receiving considerable attention. Material lifecycle analysis evaluates the cost/effective tradeoffs at each stage of a material's life: feedstock, fabrication, performance, recycle, and disposal. The U.S. Bureau of Mines investigates a material's lifecycle using technical cost models augmented with decision and impact analyses. Results of these studies are useful in gaining a better understanding of current material selections and illustrating the multifaceted issues associated with engineered materials in today's society.

Jan 1, 1992

By Erich U. Petersen

Recognition of mineralogical and chemical zoning patterns associated with mineralization is an integral part of mineral exploration. Even though the origin of zoning may not always be known, zoning patterns as expressed by the systematic distribution of ore and gangue minerals, alteration or elemental assays (soil and rock geochemistry) have received much attention and are extremely useful in guiding exploration efforts toward locating economic mineralization. By contrast, the potential of using zoning information recorded in solid-solution minerals to address practical geological-engineering problems has received less attention. Solid-solution minerals can provide critical information for common problems faced in exploration, mine development and valuation. Mineral zoning information from solid-solution minerals can now be easily obtained because advances in electron microprobe instrumentation have made these instruments a most efficient, accurate, economical and practical tool for analysis of large numbers of samples. Now entire mines and districts can be studied in a timely and cost-effective manner as required by modern mineral exploration and mining practice. This article shows how knowledge of the composition of fahlore minerals can be used in addressing important problems in exploration, development and valuation. Situations are described in which drilling intersected "low grade zones" (Case one: Orcopampa, Peru, precious metal system) and where there was a need to determine the "lateral correlation of multiple ore intercepts" (Case two: Sheep Creek, Montana, sediment-hosted sulfide deposit).

Jan 1, 1992

By Ian Martin

A precious metals refinery’s switch to personal computer-based, three-dimensional piping design saved many hours in the design of a South African precious metals refinery. Bateman Minerals and Industrial provided engineering, procurement and construction management services for Impala Platinum Limited-Refineries’ new $60 million refinery in Springs, South Africa. This project is one of the largest platinum refineries in the world. Bateman evaluated a new design method during this project that involved developing a three-dimensional model for the project. The new method saved time by reducing the man-hours required to generate complete project documentation, including plans, sections, isometrics and material takeoffs. The new method also saved design and construction time by allowing designers to detect clashes before construction began.

Jan 1, 2000

By Rahul Singh, Sunil Kumar, Erich Dohm, Maoming Fan

The rapid increase of P2O5 use for food, biofuels, and LiFePO4 batteries etc. accelerates the depletion rate of phosphate reserves. In the phosphate industry, a significant amount of ultrafine phosphate has been discarded as slime tailing due to processing difficulties. The major problems associated with ultrafine particle flotation are low probability of bubble-particle collision and adhesion, and high probability of unwanted gangue particles entrainment. This paper investigates the enhanced ultrafine phosphate particle flotation probability by Eriez’ CavTube generated fine/ ultrafine bubbles and the improved flotation selectivity by wash water etc. Ultrafine phosphates with various gangue minerals of quartz/muscovite, calcite/dolomite, and iron/ silica were studied. Microscopic observations show that the entrained ultrafine gangue minerals can be minimized by using wash water in column flotation. A three-factor threelevel central composite experimental design was conducted for ultrafine phosphate flotation. For comparison, both benchtop mechanical cell and laboratory column flotation tests were performed at their optimal respective flotation conditions. Using Eriez CavTube column flotation technology for Industries Chimiques du Senegal (ICS) ultrafine slime tailings, a concentrate grade of 36.0% P2O5, was achieved at 89.4% P2O5 recovery. Improved flotation performance was achieved using column flotation as compared to benchtop mechanical cell flotation. The benefits of Eriez’ column flotation technology realized from this study include the high P2O5 grade and recovery.

Feb 1, 2024

By Mehmet Bugdayci, Onuralp Yücel, Yeliz Demiray Cucurachi, Ahmet Turan

The production of strontium (Sr) metal from its oxide via an aluminothermic process under 1–5 mbar pressure was examined in this study. SrO of 99%purity by weight was used in the experiments. The effects of stoichiometry and the duration of the process on the efficiency ratio of the metallic strontium were examined. The effects of functional additives (BaO, CaO, CaC2) were also examined. Characterization was carried out using X-ray diffraction spectrometry (XRD), atomic absorption spectrometry (AAS) and flame photometry techniques. The highest Sr efficiency ratio obtained was 96.89% in the experiment conducted at 1250 °C with 300% Al stoichiometry and 300% BaO stoichiometry.

Aug 7, 2020

By Levent Ozdemir

An extensive study involving laboratory testing and computer modeling has been performed to assess the technical and economic feasibility of utilizing the recently developed minidisc cutters on roadheaders for hard rock mining. The results show that heavy duty roadheaders fitted with minidiscs can excavate hard rock formations at acceptable production rates and cutter costs. This paper presents and discusses the results of this study together with the ongoing developmental efforts of this technology, which include laboratory testing of a roadheader cutting drum with minidiscs and full scale field testing of a machine in hard rock

Jan 1, 1995

By L. H. Munson, D. E. Hadlock, L. F. Munson, R. L. Gilchrist, P. D. Robinson

All uranium mills are required to perform sampling and analysis for radioactive particulates in their gaseous effluent streams and in the environment. Pacific Northwest Laboratory was requested by the U.S. Nuclear Regulatory Commission (NRC) to provide technical assistance to them for their Uranium Mill Health Physics Appraisal Program. In conducting appraisals, air sampling methods used at NRC-licensed mills were reviewed and several deficiencies noted. This paper includes only environmental and effluent particulate sampling although much of the information is applicable to both in-plant and environmental samples. First, the components of a proper sampling program are discussed: program objectives, program design, sampler design, analyses, quality assurance, and data handling. Then the specific deficiencies, or the "pitfalls" from the first 8 mill appraisals are discussed. The first consideration in establishing an air sampling program is defining the objectives of the program. What is air sampling suppose to accomplish? Many of the deficiencies we have observed have resulted because the desired objectives were not clearly established in the minds of the radiation safety staff. PROGRAM OBJECTIVES An environmental air sampling program ought to fulfill the following seven objectives. The first is to: 1) [demonstrate regulatory compliance]. Although a goal of most programs, regulatory compliance, is not well understood. One has not only to comply with the conditions of the source materials licensee, but one must also demonstrate compliance with 10CFR20 and 40CFR190. For example, 10CFR20.106 states: "A licensee shall not possess, use, or transfer licensed material so as to release to an unrestricted area radioactive material in concentrations which exceed the limits specified in Appendix B, Table II of this part .... For purposes of this section, concentrations may be averaged over a period not greater than one year." Even if a mill's license does not require sampling at the site boundary of maximum concentration, a sample may be necessary to demonstrate compliance with 10CFR20. Most mill personnel are painfully familiar with 40CFRl90.10, which states: "Operations.... shall be conducted in such a manner as to provide reasonable assurance that: (a) The annual dose equivalent does not exceed 25 millirems to the whole body.... of any member of the public as the result of exposures to planned discharges of radioactive materials, radon and its daughters excepted... from uranium fuel cycle operations..." This means a licensee's sampling program must give "reasonable assurance" that the member of the general public receiving in the most exposure gets no more than 25 millirems per year. The sampling program necessary to provide that assurance may or may not be a license requirement. However, merely meeting the license requirements and the explicit regulatory requirements does not necessariarly ensure an adequate effluent and environmental air sampling program. The second objective of the environmental air sampling program, is to 2) [identify the source(s) of contaminants]. This will include not only the routine program, but special sampling for verification of sources and nonsources. Only after sampling can a mill operator be assured that roof vents, laboratory hoods, and other localized ventilation systems are not making a significant contribution to environmental releases. An environmental sampling program should also allow the mill operator to fulfill the third objective, to 3) [estimate exposures]. Even before 40CFR190, a sampling program should have provided the mill operator with the information necessary to determine the dose to the "fence post" person, or at least to determine if doses were well below the 10CFR20 limits previously allowed. The program should 4) [detect and measure unplanned releases]. If there is a fire, a scrubber failure, or if a drum of yellowcake breaks open, measured releases will almost always be lower than conservative estimates. Whether or not a system to provide sampling during accidents is needed is almost always a cost-benefit decision. In general, uranium operations do not sample just in case an accident may occur. Yet they may decide on continuous air sampling in lieu of intermittant sampling partially because of the potential for accidents. Another objective of air sampling is 5) [to provide information on the effectiveness of control systems]. This is always a concern with new or modified equipment and may dictate sampling frequency in other situations as well. For instance, if a small leak in a bag filter cannot be detected by other means, then more frequent stack sampling may be indicated. A routine effluent and environmental monitoring program should also fulfill the sixth objective,

Jan 1, 1981

By Gordon Miner

GENERAL DESCRIPTION At the Star mine, Hecla Mining Co., located in Burke, Shoshone County, ID, the mining method is horizontal slicing (timbered or untimbered) cut-and-fill using hydraulic sand backfill. Back stoping as well as breast stoping is used; see Fig. 1. The annual produc¬tion from all cut-and-fill mining is 259 816 t (286,400 st). The average depth ranges from 366 to 2408 m (1200 to 7900 ft). A majority of the tonnage comes from an average depth of 2240 m (7350 ft). Average travel time to the stope is 1 hr. GENERAL ORE BODY REQUIREMENTS AND LIMITATIONS Size and Ground Conditions The ore body is 610 to 1219 m (2000 to 4000 ft) along the strike and 2408 m (7900 ft) on the dip, with an average vein width of 2.6 m (8.5 ft). The dip is essentially vertical. The ore body is heavily sheared and broken on the main fault structures; it is more competent on the wall veins but everywhere subject to rock bursting at depth. The hanging and footwalls are strongly fractured on the main fault structures, again more competent but still fractured on the wall veins. All host rock is Revett quartzite. Value and Production Requirements The ore value is $56 per ton. Production require¬ments are 1089 t/ d (1200 stpd), five days per week. Why Cut-and-Fill? The slusher extraction method is the most satisfac¬tory and practical for narrow vertical veins with sheared walls. The method must be quite selective to be com¬mercial. The veins are too narrow for rubber-tired ex¬traction and the grade is not high enough to make resuing practical. DETAILED DESCRIPTION Development Access to the main shaft is by the 3.2-km (2-mile) main haulage tunnel. The level intervals in the vertical timbered shafts are 61 m (200 ft). Vein development is by crosscut and laterals located 30.5 m (100 ft) into the vein wall. Vein crosscuts are on ±61 m (200 ft) centers. Access to the vein is by raises carried up with the stope. The raises are equipped with four wood¬cribbed chutes (two orepasses reinforced with angle irons, one manway, and one timber slide, Figs. 2-6). The initial cut is located 6.7 m (22 ft) above the main level (Fig. 1). Stoping Cycle Detail Sampling: Grab samples are taken from the mine cars. Channel sampling of the faces and backs is done when necessary. Drilling: For stope drilling, Ingersoll-Rand 300M percussion drills are used, with Ingersoll-Rand 300M and Gardner-Denver RB83M stopers, used for back stoping. Breasting down is done with Gardner-Denver S83FM jacklegs. The back stoping rounds are 0.9 to 1.8 m (3 to 6 ft) and the breast stoping rounds 1.5 to 3m (5 to 10 ft). Blasting: For stope blasting DuPont Tovex 100 watergel with fuses and igniter cord is used primarily. Approximately 60% of the blasting is done with am¬monium nitrate-fuel oil (ANFO). For development headings and shaft sinking, DuPont Drivex watergel with Ensign Bickford Nonel Primadet primers is is used. Mucking: Broken ore is removed entirely by slusher in the stopes. These are mostly 3.7-7.5-kW (5-10-hp) Ingersoll-Rand air-powered or 7.5-37.3-kW (10-50-hp) Ingersoll-Rand electric-powered. In the horizontal de¬velopment headings Eimco 12B and 21 and Atlas Copco LM-56 overshot mucking machines and a 0.76 (1 cu yd) hydroelectric Wagner HST-1 LHD (load-haul-dump) unit are used. Rockway for Extraction: The cribbed chutes (Fig. 7) are nearly vertical and hexagonal in shape and are made of spaced 152 x 203-mm (6 x 8-in.) timber, reinforced with varying weights and sizes of angle iron, depending on wear requirements. Rectangular cribbed chutes are used where ground pressure is not a problem. Cribbing is added in 2.4 or 3-m (8 or 10-ft) extensions accord¬ing to the floor height (whether timbered or untimbered). See Figs. 8 and 9. Backfilling: Backfilling is done with hydraulic sand consisting of classified mill tailings at 65% solids. The fill contains approximately 20% 325-mesh fines. The tailings are pumped 3353 m (11,000 ft) at 50-55% solids 22.7 dry t/h (25 dry stph) with a duplex piston pump. Cycloning increases the tailings density to 65% solids. Fill storage is in a 998-dry-t (1100 dry st) agi

Jan 1, 1982

Allis Mineral Systems' Grate- Kiln system can economically convert low-grade iron ore into high- grade iron-ore pellets suitable as feed material for blast furnaces for making steel. These pellets can also be fed to a direct reduction process for making sponge iron. The Grate- Car system combines the company's [ ] Grate-Kiln system for iron-ore pelletizing and Accar system for iron- ore reduction. The Grate-Car system consists of a traveling grate, a ported rotary kiln and a rotary cooler that are coupled in series. This system eliminates the pelletizing plant's rotary kiln and annular cooler. It reduces the need for some auxiliary equipment. This results in lower capital cost and lower energy consumption. The traveling grate provides that static bed handling necessary for heat hardening pellets before their discharge into the kiln. The ported kiln provides the reducing atmosphere with a more precise means of controlling the kiln axial temperature profile than conventional rotary kilns.

Jan 1, 1997

By M. C. Roberts

The consumption of industrial minerals, like most other commodities produced from the earth, depends on the demand for the goods and services that use these materials. Minerals are not generally used directly by final consumers (table salt is a notable exception) but instead are used to either make products that are then purchased by customers, or the minerals are used to make industrial products that eventually contribute towards producing other goods and services. Therefore the demand for industrial minerals in most uses is derived from the ultimate demand for goods and services by consumers. The problem for producers of industrial minerals is that the demand for their mineral product fluctuates greatly in response to the changes in the production of goods and services over the course of the business cycle. In this respect, the producers of industrial mineral are innocent victims, subject to market fluctuations outside of their control. Because the demand for most minerals depends on the demand for the product and because minerals typically make up a minor portion of the costs of producing the product, changes in the price of the mineral often do not influence demand for it to a significant degree in the short run. This is described as a very low price elasticity of demand, as shown by the steep slope of the hypothetical demand curve in Figure 1. This demand curve shows that changing the price of the mineral does not alter the quantity demanded very much, but shifts in the demand curve will be the important determinant of the quantity of the mine.ra1 that is sold. The shifts are caused by the changing demand for the products using the mineral over the course of the business cycle.

Jan 1, 1994

By R. L. Grayson, S. Yuan

A stochastic model for evaluating the impact of the reliability and maintainability of shovels and trucks on the operational effectiveness of shovel-truck mining systems is presented. In the model, the Markov modeling technique is used to analyze the operating status of a shovel-truck mining system. Then, simulation is used to study the productivity of a shovel-truck system in a particular state. Finally, the relationship between the effectiveness of a shovel-truck system in terms of productivity and the reliability and maintainability of equipment is established. This relationship may be very useful to mine managers in making decisions in surface mining (e.g., regarding production process control, equipment replacement, and maintenance planning). A quantitative study is given to demonstrate how the reliability and maintainability of equipment affect the system effectiveness and how to pinpoint the parameter that has the most significant effect on the system effectiveness. The quantitative study indicated that in order to improve the system effectiveness significantly, the reliability and maintainability of the equipment need to be improved simultaneously.

Jan 1, 1995

By Daryl L. Gusey, John T. Neubert, Matthew A. Sares

The Colorado Geological Survey completed an inventory of environmental degradation associated with abandoned and inactive mines on National Forest System lands in Colorado. In the course of the inventory, areas with naturally occurring acid rock drainage were also noted. Approximately 18,000 abandoned mine- related features were inventoried, including about 900 features that are considered significant enough environmental problems to warrant further investigation. Water quality data, such as pH and conductivity were gathered at all features where water was present, such as draining adits, seepage at the toe of dumps and tailings, and standing water in shafts. Samples were taken where field tests indicated low pH andlor high conductivity, including several areas with naturally occurring acid rock drainage. Samples were analyzed for dissolved and total metals, and for selected anions. All mine locations and data collected by the field geologists were entered on field forms and, subsequently, into a computer database and GIS format. With the information provided by the inventory, the Forest Service, in cooperation with other agencies, has been able to prioritize abandoned mines for reclamation. In most cases, cleanup is approached on a watershed basis. Mines in priority watersheds have been selected for reclamation first. Watersheds where studies prerequisite to cleanup are occurring include the upper Anirnas River, Willow Creek (tributary to the upper Rio Grande), Chalk Creek (tributary to the upper Arkansas River), the Uncompahgre River, and the Alamosa River. During the inventory, evidence of naturally occurring water quality degradation was found in areas where little or no evidence of mining activity exists. These areas include the upper Alamosa River, the Middle Fork of Mineral Creek, Peekaboo Gulch, and Handcart Gulch. Water from these natural sources has been found to significantly exceed Colorado water quality standards for several metals.

Jan 1, 2000

In this study, numerical simulations of yield pillars employing the finite element method with time-dependent Drucker-Prager material model are conducted. The stress control mechanism of yield pillars on weak floor strata is studied. The development of pillar yield zone, the distribution of pillar stress and the development of failure zone in the weak floor strata are investigated. The study indicates that a properly selected yield pillar size may significantly reduce the peak stress induced in the weak floor strata and effectively control the development of failure zone in the floor.

Jan 1, 1999

By M. F. Werneke

Flotation of the carbonate, oxide and silicate minerals of copper (malachite, azurite, chrysocolla) has been the subject of much research in recent years, but few effective solutions to this problem have been found. With decreasing reserves of sulfide minerals, the economic recovery of these "oxides" appears to be an important source of copper for the future. Xanthates have been known for many years to be malachite collectors (1), but only at very high dosages, or at lower dosages following activation of the mineral by sulfide ion. Dewitt and Batchelder (2, 3) found that chelating agents such as certain oximes were collectors for malachite and azurite, but also required high reagent dosages. Fuerstenau (4) has suggested, for example, that potassium octylhydroxamate may be an effective collector for malachite, On the other hand, Balberyszski (5) has found that oxide minerals may be completely sulfidized at high temperatures with gaseous sulfur or H2S, and then floated with conventional collectors. None of the above approaches appear to offer an economically effective method for the direct flotation of these oxide minerals.

Jan 1, 1977

By Nagashi Ogushi

Geochemical prospecting method using stream sediments, soils and rock chips has been tested to see the applicability for the typical Kuroko field in Japan. Three independent anomalies have been detected in maps being shown by grav densities of cells which are represented by the results of factor analysis as well as distribution of minor elements scaled in logarithm. A small vein type mineralization which has outcrops could be attributed to the origin of them whereas the one near the surface of known Kuroko deposit to a coincidence. The addition of drill core geochemistry is required to complete the interpretation.

Jan 1, 1982

By Mark E. Gershon

Extensive efforts are under way to- ward applying computer techniques to mine production scheduling problems. These efforts are concentrated in four areas: optimization, computerization of traditional methods, heuristics and simulations. These areas complement each other rather than compete. Characteristics of each are discussed toward enabling the engineer to evaluate specific systems that may be encountered. Alternative approaches within each classification are described as well as the motivation for each.

Jan 1, 1985

By G. A. Munoz

Gold leaching of an auriferous pyrite ore from the Portovelo deposit in Ecuador indicates that noncyanide leaching systems, such as thiocyanate and thiourea, are not as effective as the traditional cyanide system. For example, whereas approximately 95% of the gold can be leached from the ore with cyanide, only about 50% gold dissolution can be achieved with a thiocyanate leaching system. Electrochemical measurements indicate that gold is not cathodically protected by pyrite in these systems. Based on the results of preliminary diagnostic experiments, it appears that gold dissolution in thiocyanate and thiourea systems is limited by passivation due to the formation of either elemental sulfur or sulfur compounds on the gold surface.

Jan 1, 1999