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Because surface mining removes the original plant cover from the land and exposes the soil, special care is needed. Until the mined land is stabilized by revegetation, snowmelt and rainfall can pick up sediment and erode mined lands much faster than undisturbed areas. Sediment control is an important aspect of protecting the environment during mining and reclamation because without it, large amounts of sediment can clog streams, increase the risk of flooding, damage irrigation systems, harm aquatic habitat, and limit the use of water for other purposes. Stream quality can be affected many miles downstream from the mine. Before SMCRA was implemented many streams were degraded by uncontrolled sediment from mining. Sediment is controlled through careful planning and a design that incorporates a variety of measures that work together to reduce soil erosion at the mine. Disturbed areas are graded, and some areas terraced, to achieve stable slopes, reduce runoff water velocity, increase infiltration, and divert runoff into drainage channels so that it flows away from unvegetated, erodible areas. Grading along the slope contour and scarify in gun vegetated slopes with bulldozer track marks help prevent erosion by slowing down the flow of water. Runoff from haul roads is controlled by culverts and roadside ditches. Sedimentation ponds or other forms of sediment control are required at all mines to minimize the amount of sediment leaving the site.

Jan 1, 1992

By C. A. Stewart

I. INTRODUCTION AND GENERAL STATEMENT OF RESULTS. The field-work upon which this paper is based was done in the summer of 1910, and was made possible by the courtesy of the Imperial Copper Co., which gave me access to its property. For their kindness in this respect I wish to express my thanks to W. F. Staunton and Meade Goodloe. Moreover,. B. F. Smith and G. B. Gentry, mining engineers in the employ of the company, gave invaluable assistance by placing maps,. etc., at my disposal, and by discussing with me the problems of the district; and it is a great pleasure to acknowledge this indebtedness to them. In order that the significance of some of the details that follow may be better appreciated at first reading, a general outline of the conclusions reached is given here. In the Silverbell mining-district a series of Palaeozoic limestone blocks is completely surrounded by post-Palaeozoic igneous rocks, intruded in the following order: alaskite, alaskite-porphyry, biotite-granite, andesite, and quartz-porphyry. The biotite-granite is believed to represent a differentiation of the. magma from which the alaskite-porphyry came ; and this conclusion-has an important hearing on the origin of the ores. The intrusion of both alaskite-porphyry and biotite-granite was followed by the emission of magmatic waters, which sericitized and silicified the alaskite-porphyry and granite, and produced in the limestone, by the addition to it of silica, iron, and alumina, great masses of garnet, quartz, and wollastonite. Following close upon these solutions came metal-bearing magmatic waters, which impregnated porphyry, granite, and alas kite with cupriferous pyrite, and deposited in the garnet zones chalcopyrite and copper-bearing pyrite that make important bodies of contact-metamorphic ores. Secondary enrichment has taken place in the disseminated ores in the igneous rocks,. raising their copper-content to 2 per cent. in some cases,. and extensive drilling has been undertaken to block out these deposits. East of the contact-metamorphic deposits there is a fissure-vein of lead-silver ore in the quartz-porphyry. This rock is distinctly younger than the alaskite-porphyry and the granite; and the lead-silver ores belong, therefore, to a period of mineralization distinctly later than the copper-deposition.

May 1, 1912

By J. B. Salsman

As part of the research effort on investigating the effects of microwave energy on the chemical and physical properties of minerals and ores, the U.S. Bureau of Mines (USBM) Tuscaloosa Research Center has conducted research to measure the dielectric properties of these materials. The objective was to establish a reliable database for use in predicting the effects of microwave heating on a wide range of minerals. The dielectric constants and loss factors of minerals, commonly referred to as the dielectric properties, were determined utilizing the theory of microwave propagation through an open-ended, air-filled coaxial line that was terminated at its open end with the particular mineral under investigation. In this phase of microwave research, the USBM measured the dielectric properties of powdered minerals with medium to high electrical conductivities in the frequency range of 300 MHz to 3 GHz and as a function of temperature from 25 to 325 °C. Since the minerals were prepared as powders, techniques were used to relate the measured dielectric properties of the powdered minerals to the dielectric properties of the mineral at its theoretical or natural density.

Jan 1, 2010

By G. J. Abbaschian, A. B. Gokhale, M. M. Kunjapur

"A laboratory scale model furnace was constructed for obtaining radially inward oriented columnar grains in disc shaped castings. The furnace consisted of eleven circular, concentric, equispaced resistance heaters on each half of a split graphite mold. Water or air flowing through a copper pipe along the periphery of the disc constituted the heat sink. After filling the mold, the heaters were turned off consecutively in top and bottom pairs from the rim towards the center, causing the temperature gradients to move inward. Equiaxed structure was obtained at the center by turning off the inner coils together when desired. Sn:15%Pb alloy was used to cast integral blade disc castings using the above technique to obtain dual-property discs with a central equiaxed structure and an outer columnar grain structure projecting inwards from the blades to the rim. A numerical technique was used to predict the temperature profile in the disc during solidification, and good correlation was obtained with the experimentally measured temperature profiles. The corresponding heat transfer coefficient values obtained were h = 544 Wm- 2k-1 (0.013 cal/cm2- ° C-sec) for cooling between metal and chill and h' = 71 Wm- 2k-1 (0.0017 cal/cm2- ° C-sec) for the heat input from the hot mold to the liquid metal. BackgroundHigh temperature alloys used in the current generation of gas turbine engines have evolved through two main stages of development: in 1950's, the increase in the efficiency of gas turbines was paced by improvements in alloy design, which led to the development of Ni and Co-based superalloys (1). By mid-1960's, it was realized that improved alloy chemistry alone was inadequate in meeting the increasingly stringent service requirements. The focus of research then shifted from alloy development to process development, and resulted in the introduction of directional solidification (DS) techniques for the production of turbine blades and vanes (1,2).Under typical operating conditions, the blades and vanes are subjected to aerodynamic loading, while the blades are additionally subjected to high centrifugal loading and vibratory stresses. The primary material requirements for blades may be summarized as follows (1,3):•,High creep resistance•,Good high temperature tensile strength (typically in the range of•,275 to 550 MPa at temperatures in excess of 750°C)•,Resistance to both low cycle and high cycle fatigue (LCF and HCF)•,Resistance to erosion, corrosion, and oxidation•,Resistance to thermal fatigue"

Jan 1, 1986

By Charles Anema

The Mancarried and Helicopter Receivers were developed under the contract for trapped miner location. This program was a five phase program with 15 mancarried and 5 helicopter production receivers delivered under Phase IV and equipment documentation required under Phase V.

Jan 1, 1976

By George E. Aikens

Prolonged subzero climatic conditions impose some unique engineering problems for the developer and operator of open-pit mines in the Far North. The remoteness of the job site and the extremely cold, long, dark winters severely tax both man and machine in the quest for the Arctic's rich mineral wealth. Undoubtedly the singular most troublesome problem for the engineer is Permafrost which underlies about 201o of the land area of the world and about 85% of the state of Alaska. Permafrost has its impact on building construction and mine excavation, while posing a more pervasive threat to the-delicate ecologic balance within the Arctic wilderness. Yet the difficulties associated with mining up North may not be as overwhelming as has been previously supposed. For example, the lowest temperature recorded at Point Barrow is -560F, whereas Montana has recorded -69.7° F.. There are no specially designed machines for mining and construction in the Arctic, and efficient equipment utilization is maintained through proper operation and servicing techniques. However, neither equipment or people can be assumed to function normally at -40°F. Special techniques in drilling, blasting, and ripping are being used to yield economically competitive ores. Overall, a fundamental understanding of the nature of Permafrost will allow the engineer to deal expeditiously with an Arctic mining venture and at the same time to deal fairly with Arctic environment.

Jan 1, 1972

By F. Baczek, S. S. Rocks, D. Chaiko, T. Walters

The atmospheric leaching of chalcopyrite concentrates using acidic ferric sulfate lixiviants is well known to suffer from slow leach kinetics and poor copper recoveries. A number of approaches have been proposed for improving both leach kinetics and recoveries in this system. Many of these, while effective, suffer from high CAPEX and/or OPEX. As many mine sites begin transitioning from heap leaching of copper oxides to processing of primary copper sulfides, cost-efficient leach processes that are compatible with existing SX/EW processes will be needed to maintain existing cathode production. To this end, FLSmidth is exploring process options and reactor technology for the hydrometallurgical processing of primary sulfides. One approach that appears to be highly effective at increasing copper recoveries takes advantage of the enhanced reactivity of transitory, surface-defect structures generated during particle fracture. Significant process efficiencies are gained by matching the rate of grinding to the rate of electrochemical leaching in Mechano-Chemical leach processes. The patent-pending FLSmidth® ROL process uses a Stirred Media Reactor (SMRt reactor) to achieve copper recoveries of 97+% in 6 hours or less. This approach overcomes many of the surface passivation problems that have hindered other atmospheric leach processes. New insights to leach mechanisms are presented.

Jan 1, 2015

In this study, we develop a detailed model of the likely future carbon footprint of primary copper supply. We develop a peak copper production model, based on a detailed copper resource data set, and combine this with a comprehensive life cycle assessment model of copper mining and milling to predict greenhouse gas emission rates and intensities of Australian and global copper production up to 2100. By establishing a quantitative prediction of both copper production and corresponding greenhouse gas emissions of Australian and global copper industry, we then analysed the emissions intensity of various energy input scenarios, such as business-as-usual, solar thermal electricity and solar thermal electricity with biodiesel. The Australian Government has an aspirational goal for long-term greenhouse gas emissions of an 80% reduction from the 2000 level by 2050. For the copper sector, this means moving from about 12.6 Mt CO2e in 2000 to a goal of some 2.52 Mt CO2e in 2050 (assuming equal emissions reductions across the economy). Based on the energy sources modelled, only the solar thermal plus biodiesel scenario was capable of achieving this goal at about 0.15 Mt CO2e, since the solar thermal alone scenario still includes normal petro-diesel as a major source of emissions. Overall, it is clear that there are abundant resources which can meet expected long-term copper demands, the critical issue is more the carbon (and environmental) footprint of different copper supplies and use rather than how much is available for mining. It is clear that the switch to renewable energy can have a profound impact on the carbon intensity of copper supply, even allowing for increased energy intensity as ore grades decline, and a complete conversion to renewable energy will position the copper sector to meet existing annual greenhouse gas emissions targets and goals.

Aug 1, 2013

By Charles Will Wright

This paper has been written to aid the owner of a small gold mine or prospect in preparing a report on his property for the purpose of interesting capital. If an owner can afford to do so, he should employ a mining engineer of recognized standing and experience to examine and report on his property, but many owners of small -mines and particularly of prospects cannot make the expenditure required for this. Further, many of them do not know how to prepare a description which will cover those features of a deposit on which a potential investor promises his opinion as to its worth. If such an owner is convinced that he possesses an orebody of sufficient grade and size to warrant the required expenditure for a thorough investigation and wishes to present his property to prospective investors, then the following suggestions concerning the proper way to sample his deposit, estimate the tonnage of developed and probable ore, and prepare a report may be of assistance.

Jan 1, 1933

Calcium carbonate has three polymorphs: calcite, aragonite, and vaterite. Needlelike aragonite CaCO3 with a high ratio of length to diameter (aspect ratio) is widely used in plastics, rubber and ceramics as a filler and in pigments and paints as a carrier. This paper investigated the influence of H3PO4 dosage, reaction temperature, CO2 flow rate, and initial Ca(OH)2 concentration on formation of needlelike aragonite CaCO3. It was found that the presence of H3PO4 in Ca(OH)2 suspension resulted in rapid formation of (Ca5(PO4)3(OH)) crystal nuclei, which facilitated nucleation and growth of aragonite CaCO3 on the formed (Ca5(PO4)3(OH)) crystal surfaces. The results revealed that H3PO4 addition of P/Ca of 0. 2~0. 3, high temperature of 75~85 °C, low CO2 flow rate and initial Ca(OH)2 solid concentration of 1. 5 %~5. 6 % are beneficial to formation of aragonite. Well crystallized needlelike aragonite CaCO3 whiskers with length > 20 µm and aspect ratio > 15 were directly synthesized.

Jan 1, 2014

By Lawrence K. Nordell

This paper reviews practices used In the selection and sizing of belt conveyors and stacker systems commonly used in crushing and grinding plant facilities. Historical and modern methods of sizing this equipment are presented. The new methods Include: 1) probability theory applications for establishing component reliability, 2) "Monte Carlo" simulation techniques used in evaluating alternative system designs and in establishing service factors and corresponding availability Indices of each system, 3) quantifying the system and component operating characteristics using computer assisted modeling tools simulating rigid body and elasto-mechanic behavior for starting and stopping large and/or complex belt conveyors.

Jan 1, 1982

By Gary R. Gavan

This report presents the documentation and User's Manual for a data retrieval and report generation computer program. The program operates on a data base containing over 19,000 pieces of coal mine equipment in use in 1976.

Jan 1, 1979

By R. K. Sinha, B. S. Choudhary, Desh Deepak, A. K. Mishra, Hemant Agrawal, Shankar Kumar

Despite several methods (empirical, statistical and machine-learning tools) to calculate blast-induced ground vibration, it is not easy to predict and simulate blast vibration precisely under varying blasting loads and strata conditions due to complications in the blasting procedure. In this study, field blast data were simulated in Ansys software using explicit dynamics, and ground vibrations for 20 single-hole blasts were monitored. The densities of emulsion explosives were in the range of 0.9 to 1.15 g/cm3. In the laboratory, rock properties were determined from rock samples collected from the mine site before blasting. The in-hole velocity of detonation (VoD) and density of the emulsion explosive were also determined and used in numerical analysis to know the ground vibrations at specific points. The results of ground vibrations predicted by the model were validated using field data.

By G Harbort

The use of geological data for optimisation of operating plants has become a significant part of the modern process mindset. The underlying principle is to convert spatial geological data into metallurgical information to drive production and mine planning, blast design, blending strategies and plant set-up. Increasingly the process designer is required to interface with geological and mining staff to propose the best investment strategy for a project’s benefit.The geometallurgical model development for the Zafranal copper-gold project commenced in March, 2010, several months after the start of a major drilling campaign by AQM Copper Inc. The initial evaluation stage required review of historical Teck RC data to determine areas of metallurgical interest within the project. As drilling transitioned from RC to diamond drilling, core that was considered representative of the resource was selected and subjected to MLA mineralogy analysis. When coupled with sequential copper analyses this allowed calibration of an assay derived mineralogy model, allowing process concept options and a preliminary test program to be developed. This Phase 1 test program provided a preliminary process design, operating costs and anticipated concentrate grades and recoveries. Both this data and resource estimation were used to generate a preliminary Whittle pit optimisation based on maximising net smelter return, which in turn fed into a preliminary mine plan. The preliminary mine plan, in conjunction with geological logs and core results was used to develop a phase 2 metallurgical test program, where variability tests were conducted throughout the resource and composites formed to investigate specific years of the mine plan in locked cycle flotation. In addition comminution tests were modelled against geometallurgical domains allowing comminution components values to be calculated for 36?000 m of core. A flotation geometallurgical model was developed and incorporated into the resource model allowing concentrate grades and recoveries to be estimated on a block-by-block basis.

Sep 5, 2011

By I. Murray, N. Geoffroy

"Buried pipelines, tanks and other similar equipment are almost always present on large scale industrial sites, including in the oil and gas fields. However, as the proverb “out of sight, out of mind” suggests, it is easy to overlook proper maintenance procedures and simply assume that corrosion protection measures in place are working correctly. Unfortunately, this is not always the case, leading to significant environmental damage and loss of production. This paper describes several cases from various industries where buried equipment failed because of corrosion, sometimes with catastrophic results. It also presents various strategies, based on experience and new research, to help predict and prevent damage to underground metallic structures.INTRODUCTION Metallic underground structures are extremely common in industrial and commercial settings for numerous reasons. Burying pipes, tanks, wires and other similar equipment has numerous advantages: it provides significant protection from mechanical damage, frees up ground space that can be used for other purposes, requires little to no support structure and is generally more esthetically pleasing. However, this last benefit can also be considered the most significant disadvantage of underground equipment: becoming invisible and forgotten. While every engineer is aware of the importance of preventive maintenance, it is also human nature to somewhat forget about equipment that is hard to inspect and assume that everything is fine. This is unfortunately not always the case and failures in industrial settings can have extremely serious consequences. While economic aspects immediately come to mind (loss of production, cleanup cost, etc.), failure of underground equipment also results in an environmental and therefore public relations nightmare, especially in the oil and gas field. Leaks that would have been considered negligible in the past can now make national headlines and perfect reliability, while probably impossible to achieve, is now the goal of most companies. While environmental damage (real or perceived) is most often associated with leaks in the oil and gas industry, it can also affect the mining world. For example, the authors have worked on a project where a buried slurry pipeline had ruptured in the ground, causing a release of perfectly inert tailings. While the economic loss was low, the leak was reported in local media and caused a public relations problem."

Jan 1, 2017

By George A. Savanick

Borehole (slurry) mining, in which a tool incorporating a water-jet cutter and a downhole slurry pump mines phosphate through a borehole, was field tested in northeastern Florida as part of a Bureau of Mines program to increase the domestic availability of critical minerals. Approximately 1700 tons (1.54x106 kg) of phosphate ore were mined at 40 tph (10.1 kg/s) from a depth of 250 ft (76 m). The borehole was filled with water during mining for roof support and to assist slurry pumping. Underwater cutting was enhanced with an air-shrouded water jet. Mined cavities were backfilled to prevent subsidence after abandonment. Roof subsidence during mining was avoided only when the cavity was filled with water. Environmental monitoring before, during, and after mining included hydrological studies and measurements of water quality. Significant water quality changes occurred only in the zone being mined and were confined to the immediate area of the borehole.

Jan 1, 1983

By W. L. Staker

The Bureau of Mines investigated the use of shredded automobile scrap for copper cementation. Air agitation was used to improve the cementation rate and prevent excessive buildup of copper on the iron. The pieces of scrap were too large to be properly evaluated in the laboratory; therefore, a pilot scale test unit was constructed and the process tested at field locations. Pregnant solution was obtained from industrial leaching operations, processed in the test unit and the barren solution and cement copper were returned to the plant process stream. The test results showed that the air-agitated launder containing auto-mobile scrap was an effective means for recovering copper from leach solutions. A continuous l4-day test run was made without a noticeable decrease in cementation efficiency. The most suitable scrap product was obtained from incinerated automobile hulks shredded in a hammer type of shredder. However, it was necessary to remove small pieces such as nuts and bolts because they interfered with the discharge of the copper product.

Jan 1, 1976

By Deborah A. Kopsick

Several minerals were observed and collected in a small gully originating from a weathered coal processing waste (gob) pile in Barton County, Missouri. The rapid alteration of these various minerals after collection suggested that they might represent a dehydration sequence. X-ray diffraction of the dehydrated and rehydrated minerals deposited on the gob pile indicated the presence of the monohydrate and heptahydrate forms of ferrous sulfate, szomolnokite and melanterite respectively. The occurrence of melanterite (FeSO4.7H2O), was limited to isolated areas of ponded water while szomolnokite (FeSO4.H2O), was associated with the outwash areas of the pile. Laboratory dehydration of melanterite collected at the gob pile revealed the formation of rozenite (FeSO4.4H2O), an intermediate form of ferrous sulfate. Szomolnokite was shown to be the stable form of these ferrous sulfates during these experiments while melanterite and rozenite were shown to alter readily. Chemical analysis of szomolnokite revealed enrichment in Fe, Mg, Zn, Cd, Cu and Mn relative to the chemical composition of the gob ad the lechate generated from the gob wastes. Although this gob pile had been weathering for more than 35 years, significant concentrations of trace metals were still being released from the pile through the generation of leachate and the formation of various soluble metal enriched ferrous sulfate minerals.

Jan 1, 1982

By Ivo André

Sorption of copper ions from aqueous solutions by dried biomass of the aquatic plant Potamogeton luscens was studied at laboratory scale. The aquatic plant was collected in water resources in Brazil, washed, dried at 60°C and ground in a bladed mixer. Sorption experiments were conducted in agitated flasks and in a packed bed column. Maximum copper removal was obtained between pH 5.0 and 6.6 when copper was present in the ionic form Cu'. Sorption followed the Langmuir isotherm with saturation attained at 35 mg/g. Free energy of sorption was found, to be of the order of -25 kJ/mol. Sorption kinetics data were better described by a second order reaction and rate constants were calculated in 0.030 1/(min.mg) for - 4.0 mm particles and 0.081 1/(min.mg) for - 0.59 mm particles. Removal of metal ions in a packed bed column showed that Potamogeton luscens biomass can be used in several sorption/dessorption cycles. After sorbent saturation, copper ions can be recovered from the loaded biomass by elution-with H2SO4, solution. Main mechanism responsible for heavy metal uptake was found to be ion exchange. Results are discussed in terms of the surface properties of the biomaterial, solution chemistry of copper ions and thermodynamics parameters.

Jan 1, 1995

By Tim C. Webb

For almost 350 years, industrial rocks and minerals have been produced, used locally and exported from New Brunswick to markets throughout the world. Up until the early 1960s, commodities like grindstone, building stone, gypsum, and limestone served as the foundation of the province's non-fuel mining industry. The importance and high level of activity surrounding industrial rock and mineral development in New Brunswick is reflected in a multimillion dollar industry generating substantial revenue and providing a valuable service to its people. New Brunswick's varied geology is reflected not only by the diversity of industrial rock and mineral resources presently under development but also in several promising exploration and potential development opportunities. The province also hosts several industrial rock and mineral processing facilities, each with established technologies ensuring high-quality products and each with sufficient flexibility to supply customized products for various specialized niche markets. With the imminent availability of natural gas to parts of the province, the prospects for additional value-added processing and re-examination of known, yet presently undeveloped deposits, appear excellent. These variables coupled with the province's advantageous geographical location, highlighting tidewater access to global markets and within one day's trucking distance to a regional market of several million people, guarantee prompt delivery of high-quality products at competitive prices.

Jan 1, 2001