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By W. A. Haley

As far back as 1939 state laws have required reclamation of mined lands. Reclamation has been the topic of many discussions and presentations, especially since the late 1960's. In the past ten years many states have added legislation concerning the reclamation of coal-mined lands. In the near future, it seems certain that some federal regulations will be passed that will set minimum guidelines for the states to regulate. Besides the requirement of returning the land to the approximate original contour, future regulations will more than likely demand replacing topsoil from one to five feet thick. As regulations become more stringent, costs will rise accordingly. Since no one has developed a machine that can do all reclamation work by itself, it is necessary to review in detail the tools available and to select the most economical means.

Jan 1, 1976

By Rustyn Sherer

Curis, the name of a new Arizona-based mineral development company, is an acronym which stands for ?Cu? (elemental symbol for copper), ?r? (recovery), ?is? (in situ, the Latin for ?in place?). The company was created specifically to advance the development of the Florence Copper Project in Florence, AZ and to pursue other next generation copper development projects in progressive jurisdictions around the world. ?We are extremely excited about this project,? said Curis Resources president and chief executive officer Michael McPhie. ?We?re here to set the standard for Greenfield in situ copper recovery (ISCR) operations in Arizona and around the world. We believe in our people, our technology and our process; and we are passionate about our commitment to environmental stewardship and community development. We?re making a long-term investment in Florence, and in Arizona.?

Jan 1, 2011

By James L. Withiam, P. C. Kelsall

The manuscript of this paper was not available for publication when the Proceedings went to press. Should the authors elect, they may distribute copies at the time of the Symposium.

Jan 1, 1986

By J. C. Mullen

Today, the coal mining industry is more knowledgeable on the potential negative economic consequences associated with improper management of hazardous substances and various types of solid waste. The practices evaluated during environ-mental audits are discussed and example situations are shared from previous audits of coal mines and analogous situations. The importance of assessing and understanding purchasing, warehousing, safety, maintenance, electrical, operations, and environmental management practices and procedures is highlighted as a key to a successful and practical program. A waste minimization approach is presented including strategies for screening product purchases, product substitutions, and testing and record keeping.

Jan 1, 1992

By Steve Trussell, William H. Langer

"Arizona aggregate (sand, gravel and crushed stone) producers enjoyed more than a half a century of nearly constant growth in demand for aggregates. Approximately 80 percent of the aggregate produced in Arizona is sand and gravel, and 20 percent is crushed stone (U.S. Geological Survey, 2015). Figure 1 shows the generalized distribution of potential sources of sand and gravel (yellow) and potential sources of crushed stone (other colors described below). Black dots show locations of aggregate operations.Sand and gravel commonly is produced from modern river channels and terraces although some alluvial fans and high-level paleo-river terraces also serve as aggregate resources. The gravel clasts are a mix of rock types that reflect the types of rock in the source area of the rivers. Generally processed river gravels meet stringent specifications for highend uses.Crushed stone, which makes up about 20 percent of production, primarily comes from a variety of metamorphic rocks and light-colored intrusive igneous rocks such as granite (brown areas), dark colored extrusive igneous rocks such as basalt and scoria (rust colored areas), and carbonate rocks such as limestone or dolostone (green areas). Carbonate rocks are also used in the manufacture of cement and lime.Construction and aggregate production in ArizonaBecause aggregate producers have limited facilities for storing product, stockpile changes are insignificant compared to production. Therefore, demand or consumption of aggregate in Arizona is considered to be equal to production. Production figures used in this paper reflect shipments, sales or marketable production, including aggregate used by producers to make readymix concrete and asphalt. Production figures were reported by the U.S. Bureau of Mines from 1950 until 1995 and by the U.S. Geological Survey (USGS) since then. Production figures are reported voluntarily, and major operators are the primary source for these figures. Because many smaller operators do not report their production, the figures are conservative values that provide an approximation of aggregates production activity."

Jan 1, 2015

By G. J. Joy, J. P. Rider

"Technical advances in longwall mining over the last several years have resulted in much larger and faster shearers that have the capability of mining at speeds over 100 ft./min. This has resulted in a substantial increase in the amount of dust that is generated at the shearer and during shield advances. Meanwhile, increased underground coal production has put a greater demand on longwall dust control systems as some operators have had difficulty maintaining consistent compliance with federal dust standards. To address this need, the National Institute for Occupational Safety and Health [NIOSH] is investigating the effectiveness of a water spray manifold mounted on the tailgate end of the shearer body. The sprays are oriented parallel to the tailgate ranging arm, and these sprays create a water curtain confining the dust plume near the face, preventing the dust from drifting into the walkway. This redirection of dust provides a clean air envelope for the tailgate shearer operator and jacksetters working near the tailgate drum. Three different tailgate spray manifold designs were tested and evaluated at the Office of Mine Safety and Health Research [OMSHR] Pittsburgh Longwall Test Facility. Manifolds were equipped with hollow cone or flat fan water spray nozzles and evaluated at three face air velocities (500, 700, and 900 fpm) and at water pressures of 100, 150, and 200 psi. Reductions in dust concentrations were observed at six face sampling locations for all the tailgate manifold systems at each of the tested spray pressures and face velocities. Based on results from the laboratory tests showing reductions in dust concentrations at sampling locations downwind of the shearer a spray manifold was fabricated and evaluated at an underground operation. INTRODUCTION In 2012, underground coal mining in the United States produced a total of 342 million short tons, with longwall mining accounting for over 53% of this production [EIA 2013]. The longwall mining industry continues to see remarkable and significant improvements in longwall mining equipment and mining practices. Average shift production during compliance dust sampling has increased from 3,500 tons per shift in 1994 to approximately 6,000 tons per shift in 2012. A dramatic decrease in working longwall faces from 80 to 49 has occurred over the same period [Fiscor 2013]. Factors specific to longwall mines that supported productivity improvement include: higher capacity shearers, improved shield hydraulics and control, higher horsepower for equipment, wider face conveyors, and larger faces. Today, the average face width has increased to 1,188 ft., with one longwall operation reporting a face width of 1,650 ft. compared to an average of 750 ft. in 1994 [Fiscor 2009, 2014]. Panel lengths in 2013 averaged 11,307 ft. compared to 7,000 ft. in 1994. Overall production from U.S. longwalls has increased by nearly four percent from 2007 to 2012 with over 182 million tons mined annually [EIA 2013]. Given the volume and rate of coal produced on longwall faces, the potential to generate large quantities of respirable coal mine dust also exists."

Jan 1, 2015

By R. D. Hagni

Pyrometallurgical products from lime roasting of refractory gold ores, pyrite, and arsenopyrite have been examined for their mineralogy, porosity, permeability, retention of contaminant sulfur and arsenic, and potential effectiveness of gold extraction. Cathodoluminescence microscopy, supplemented by X-ray diffraction and scanning electron microscopy-energy dispersive analysis study, has shown that the products phases have characteristic cathodoluminescence properties as follows: anhydrite (CaS04), deep blue; unreacted portlandite (Ca(OH)2), deep purple; oldhamite (CaS), light yellow to rarely pink or orange; a sulfur-rich, arsenic-poor phase, violet; an arsenic-rich, sulfur-poor phase, non-CL. Within the temperature range examined (400-850°C), hematite exhibits greater porosity and permeability at the intermediate roast temperatures of 600-650°C.

Jan 1, 1993

By David H. Carlson

Mechanical sorting of "poor" rock accumulated from past native copper mining operations has been under study at the Michigan Tech's Institute of Mineral Research for several years. Prior to this work, the poor rock dumps totaling approximately 9 million tons containing an estimated 35-70 million pounds of copper (1) have been considered mainly as a local source of road aggregate used from time to time and consequently of minor value. An electro¬mechanical sorting machine developed by International Sorting Systems Corporation of Santa Barbara, California has been tested for preconcentration of the waste rock before conventional milling (2,3). The ISSC machine has possibilities for underground preconcentration of crushed mine-run native copper ores. The objective of the study described here was to provide information about limi¬tations on sortability due to characteristics of the ore and present crushing practices. When the native copper mines were in operation prior to termination in 1969, two types of ore were produced, amygdaloidal and conglomeritic. In the first type copper occurs in vesicles left by gas bubbles entrapped during rapid cooling of the tops of lava flows. The conglomeritic ore beds consist of rounded pebbles and fragments cemented together by calcite, epidote, chlorite, and feldspar; the copper occurs around pebbles, in cracks, and sometimes as partial or total re¬placements of pebbles. The copper in the conglomeritic ore usually is in finer grain sizes than that in the amygdaloidal ore, and large (plus 4 inch) copper masses are virtually absent.

Jan 1, 1970

By William Gleason

"During the past nine years the number of cellular phones connected to a network has increased from 34 percent of the world’s population in 2005 to 93 percent in 2014. These phones are powered by a combination of materials including elements such as gold, silver, copper and rare earths. And, as more parts of the world become connected to networks, the number of phones being produced, and the elements they will need, will continue to increase. The demand comes as prices for these commodities are slumping and access to the commodities is getting more difficult, technically and socially.These mobile devices have connected people around the world in ways that could not have been imagined two decades before, and, ironically, this communication has strengthened opposition to the development of the mines that produce the very materials they need to operate.In his keynote address to the 2014 SME Arizona Conference at the JW Starr Pass Resort in Tucson, AZ, on Dec. 8, 2014, John O. Marsden, SME President and president of Metallurgium, spoke to more than 500 attendees about the challenge to produce the materials that society needs while at the same time challenging the general public’s perception of mining that is often inaccurate and less than favorable.Marsden highlighted the amount of raw materials that will be needed not just for phones, but also for things such as automobiles, including electric cars, as a way to illustrate the importance of mining. Even so-called green products such as Tesla cars, which require about 317 kg (700 lbs) of aluminum, 13 kg (30 lbs) of copper and 36 kg (80 lbs) of cobalt for their eco-friendly batteries, will need materials mining provides.These are some of the numbers that the general public is often unaware of. They are part of the necessary things that mining provides for society but are rarely reported on. Instead, it is the accidents like the tailings spill at the Mount Polley Mine in British Columbia and at the Buena Vista Mine (Sonora, Mexico) that grab headlines and stick in the minds of the public, adding more challenges to an industry that already has its own complex technical challenges to deal with."

Jan 1, 2014

By Peter L. Hofmann

Significant quantities of nuclear wastes were first generated in 1944 as a byproduct of the national defense program. To establish the current inventories and future projections of nuclear waste products is not a simple task. The Oak Ridge National Laboratory recently issued a report which now constitutes the official basis for nuclear waste inventories and projections. Radioactive wastes originate from five major sources (U .S. Department of Energy, 1980b) : (1) From the commercial nuclear fuel cycle related to the production of electricity , (2) From defense related activities, (3) From institutions such as hospitals, universities, and research foundations, (4) From industrial uses of radioisotopes, and (5) From mining and milling of uranium ores.

Jan 1, 1981

By R. A. Seitz

Although the role of the collector has long been thought to play a predominant role in coal flotation, recent investigations by the authors show that the frother plays an equally important role. These investigations have included extensive testwork in several coal preparation plants and in the laboratory. The factors which were investigated include the absolute level of collector and frother addition, the ratio of frother to collector additions, the type of frother, and the particle size distribution of the feed. Results from this testwork reveal strong interactions between these factors as well as the necessity of considering these factors in order to optimize the reagent regime.

Jan 1, 1987

By L. Yan, C. Zhou, M. Reyes

"The MINER Act requires the installation of post-accident, two-way communications and electronic tracking systems for all coal mines. One communication system which can satisfy this requirement is an electrode-based, through-the-earth (TTE) communication system, which sends signal directly through the overburden of a mine. The performance of these types of systems relies on several controlling factors such as earth conductivity, overburden depth, operating frequency, TX/RX antenna length, TX/RX offset, TX/RX orientation angle and TX current. In an effort to estimate attenuation through the earth, NIOSH researchers developed an analytic solution for the electrical field distribution of an electrode-based TTE communication system for the extremely low-frequency (ELF) range (< 30 Hz) or DC excitation source. The analytic model was then validated using test data measured at an operating coal mine. The validated model can be used to optimize the operating frequency, estimate the required transmitting current, choose appropriate TX/RX orientation, and predict the performance of an electrode-based TTE system at a coal mine. INTRODUCTION One of the requirements of the Mine Improvement and New Emergency Response Act (MINER Act) of 2006 is the installation of post-accident, two-way communications and electronic tracking systems for all underground coal mines. As one of the through-the-earth (TTE) wireless communication methods available for the mining industry, the electrode-based, or linear, TTE systems establish communication by inducing a current within the earth medium by use of a pair of current probes. The resultant current is detected as a voltage by a similar set of distant probes. These probes could be an insulated piece of wire tied to two electrodes grounded at distant ends, or the grounded ends could be rails, roof bolts, or grounded electric rods. The analytical solution developed in a homogenous half-space, for this form for various transmitter/receiver (TX/RX) configurations, will be presented in this paper. The communication signals can be sent either from underground to surface (uplink) or from surface to underground (downlink). In order to achieve a successful communication link, it is necessary to understand the electric fields within the earth so that the appropriate size of transmitting antenna, TX/RX relative orientation, and operating frequency can be chosen. Hill and Wait gave the explicit forms of partial magnetic fields and partial electric fields of electrode-based TTE downlink communication with finite cable length [1]. In prior research, the E-fields of electric line transmitter were obtained for a static TX current [2] [3]. In this paper, the general and explicit forms for electrode-based TTE electric fields are developed and presented. The solutions for the extremely low-frequency (ELF) range (< 30 Hz) or DC excitation source obtained from these forms are presented. Also, factors that affect the E-field strength at RX are discussed."

Jan 1, 2017

By D. Maxton

INTRODUCTION This paper traces the application of High Pressure Grinding Rolls (HPGR) at industrial and pilot scale in Australia. The Argyle Diamond Mine installed the first of two smooth segmented HPGRs during 1990 in an open-circuit secondary-tertiary crushing application to increase throughput. In 2002 a third HPGR was added to improve liberation and so increase the recovery of smaller diamonds. The latest improvements in wear technology (tyre with tungsten carbide studs) were incorporated in the design of this machine. Extensive HPGR pilot-plant trials were undertaken during the 1990s at both the Kalgoorlie Consolidate Gold Mine and the Boddington Gold Mine. The purpose of these trials was to evaluate HPGR as a method to increase throughput, as an alternative to SAG milling, and also to ascertain if downstream benefits existed. One of the challenges for HPGR circuit designers is to translate what occurs at small laboratory and pilot scale into what is likely to happen in a full-scale circuit. Scale-up from pilot machine results is normally recommended by manufacturers. However, such tests need relatively large quantities of material, particularly if meaningful data on wear are to be obtained. Laboratory tests are preferable, as they need relatively small quantities of ore, but may be questioned in terms of how they relate to full-scale operation. Modelling and simulation have played a particularly important role in this respect in Australia. Models are available which have proven to be very accurate at being able to scale throughput and specific energy response from laboratory to industrial machines. More recently, work in Australia has also been done in developing a model which has the potential to scale laboratory wear data as well.

Jan 1, 2004

By C. A. Rowland

With the rapidly rising cost for electrical energy and the long range pre¬dictions for continued rising costs and even possible energy shortages, operation of rod, ball, autogenous and partial autogenous grinding circuits to efficiently utilize the power delivered to the mills will be demanded. This calls for a method to evaluate grinding circuit performance that is accurate, reliable and readily usable as an operating tool by supervisory, technical and operating personnel. Neither the Rittinger and Kick theories of comminution,(1) which preceded the Bond Theory by more than 50 years, had a mathematical means that could be used to predict and evaluate the performance of crushers and grinding mills used to comminute ores and rocks. This severly limited the practical use of these two theories, which were contradictory to each other. They have been superseded by the Bond Third Theory of Commnution.(1)

Jan 1, 1976

By David B. Spencer

This paper describes a process for separating non-ferrous metals such as aluminum, copper and zinc, from other residential and industrial waste by means of permanent magnets. Although the separator may be used in the recovery of non-ferrous metals from auto scrap, most of the testing to date has been aimed at recovery of non-ferrous metals from municipal solid waste, especially recovery of aluminum from the heavy fraction of a resource recovery plant. In most resource recovery plants the incoming solid waste material is first shredded and then air classified into a light and a heavy fraction. The light fraction which contains mostly paper, cardboard, etc., can be used either as a fuel for power generation or in the production of new paper products. The heavy fraction which remains consists mostly of glass, ceramics, wood, ferrous metals and non-ferrous metals. The ferrous metals may be removed from the heavy fraction by conventional magnetic separators. After primary shredding, most of the glass and ceramic is fine in size and may be screened away leaving a residue of wood, cardboard, and non-ferrous metals. This residual heavy fraction is the input material for the separator described in the present paper.

Jan 1, 1975

By G. W. Leney

Introduction and Historical Background The office and mining operations of Pacific Asbestos Corporation are located near Copperopolis, California in the foothills of the Sierras about fifty miles east of Stockton. This is historic country in the heart of the old Mother Lode gold district. Mark Twain&apos;s famous story of the jumping frog, written here, is still commemorated in an annual contest in Calaveras County,&apos; and the camp at Poker Flats, described by Bret Harte, was only a few miles from the present mine.2 Joaquin Murrieta, the famous Mexican bandit started his three year reign of terror in this vicinity,3 and Black Bart, the P08 laureate of the stagecoach robbers, held up his first stage at Funk Hill, just three miles north of the mine. His last robbery was at almost the place, on the top of the hill overlooking the Stanislaus River ferry crossing. Although this was his favorite country, and he traveled extensively through it, he was not a credit to his acclaimed profession of Mining Engineer because there is no evidence that he ever recognized the asbestos, and he was finally caught as a consequence of the robbery at the ferry.4 One of the old stagecoach roads crossed the Stanislaus River at the mine site, and the ferry landing may still be seen from the main haul road into the pit. The road itself is partly buried under the rock dumps. In spite of its location and apparently prominent exposure, the first work on the asbestos deposit was not recorded until 1904.5 Development of the present operations was started in 1959 by Jefferson Lake Asbestos Corporation, a subsidiary of Jefferson Lake Sulphur Company. Management control of the company changed hands several times and it was later reorganized under the name of Pacific Asbestos Corporation. In December, 1968, a controlling interest was acquired by H. K. Porter Company, Inc. Figure (1) shows the mill and office buildings as seen from a site near the entry road. The offices are at the left with the mill warehouse in the foreground. The conveyor at left center carrys mine concentrates up the hill from the crusher. In the background are the dry rock storage building and mill tailings piles. Since the beginning of mining operations in 1962, seven and three-quarter million tons of ore and fifteen million tons of waste have been removed from the open pit which now measures about 1400 x 1800 feet at its widest points. The lowest operating level is at an elevation of 726 feet about 325 feet below the original surface. Figure (2) shows the open pit looking toward the west end. The main haul road can be seen along the side of the pit. A shovel is operating at the bottom of the pit while a front end loader on the level above provides ore for blending. In the background are rock dumps for waste stripping. The company markets an annual production of 30-35,000 tons of chrysotile fibre in groups 4 through 7, under the Mother Lode Brand

Jan 1, 1972

By A. Goulsbra, S. Gregory, P. Gelfil, V. Martins, R. Dunne

As a general rule for gold treatment the presence of reasonable amounts of 'coarse' free gold will dictate the use of a gravity circuit. The actual particle size of gold that constitutes the por­tion of' coarse' free gold can vary widely. The larger its size the more troublesome it is, mainly because of the tendency for this gold to quickly settle out from slurries in regions of relatively low velocities. There are a multitude of places where 'coarse' gold can find a resting place, namely, in chutes, between and behind lines, in pump hoppers and in pumps themselves. Fortunately, the problems associated with recovering very 'coarse' free gold, say greater than Imm, is rare on most gold mines that have grinding and cyanide leaching circuits. For these operations it is common practice to have a gravity circuit situated within the milling circuit to recover 'coarse' free gold. Should the 'coarse' free gold constitute 15% to 20% of the total gold in a deposit then its recovery by gravity separation is seri­ously considered. As a gold mine 'matures' the availability of soft oxide ore decreases and the likelihood that harder ore having sulphide gold association increases. To maintain gold production rates in this situation either the gold grade of the treated ore must increase or more ore needs to be treated. In the latter case this is achieved by installing more grinding capacity, an expensive option, or coarsing the grind, with the downside of loss in gold recovery. In general the less expensive capital options is fol­lowed. There is, however, some upside to improve recovery when reasonable quantities of sulphide containing gold are pre­sented that can be recovered by flotation or gravity separation. Concentrates produced from these unit operations can be finely ground and reintroduced to the cyanide leach circuit to improve gold recovery. This scenario is a much less costly option than one where all the ore is ground finer. In this paper the experiences of recovering gravity gold from the Telfer Gold Mine, and gold associated pyrite from the New Celebration Mine will be discussed.

Jan 1, 1996

Underground testing was carried out by Ingersoll-Rand, Inc., under contract to the Bureau of Mines to determine the effectiveness of a machine-mounted scrubber system for ventilating the face during an extended advance. A continuous miner equipped with an integral flooded-bed dust scrubber system was instrumented with methanometers and Real-time Aerosol Monitor (RAM) dust monitors. Methane and respirable dust data were collected at brattice setbacks of 7.5 m (current operating distance), 10.5 m, and 15 m (blowing ventilation) during production shifts. Results showed that a suitable machine-mounted scrubber system can adequately ventilate the face at brattice setbacks up to 15 m. No deterioration in ventilation performance was observed as brattice setbacks were increased from 7.5 m to 15 m. The scrubber system effectively controlled face methane levels at large setbacks, though respirable dust levels increased as much as 33 pct at the operator&apos;s cab at setbacks greater than 7.5 m.

Jan 1, 1986

By G. E. Erdman

This paper presents talc milling guided by a theme of "So You Want to Be In The Talc Business". Such a theme strikes a cautionary note to warn the uninitiated of potential pitfalls, and this paper will cover briefly some of the technical traps as well as one of the larger talc milling operations. It is important to our purpose to pre- sent some of the market and mineral complications that make the business of producing and selling industrial talcs much more intricate than an outsider would perceive. Metal markets by comparison are great worldwide pools into which production streams of generally identical metals can flow over a weir of market prices. Industrial talc markets are not as well defined and often must be developed by the producer working closely with a specific customer or groups of customers to prove out the attributes of the specific product from a new property. All the negatives of a new market seem to work against the introductory talc in the forms of industry or customer reluctance to change, sales prices, cost of delivery, mode of transportation, health considerations of the minerals and many more. Just locating the potential customers for a new industrial talc may be a substantial undertaking. Thus, an analogy of the worldwide metal market might compare starting a new talc operation to trying to gather up enough fallen rain drops to be able to start a production stream of a worthwhile size.

Jan 1, 1984

By Harold F. Yde

Hydraulic tailings fill in the Butte deep level mines was based upon studies made in 1958 by the Anaconda Company Mining Research Department, which published Bulletin No. 35, entitled "Hydraulic Stope Filling". Since then, many things have changed. At the time of the Research Departments study, dry mine tailings were hauled by rail cars from the Anaconda tailings ponds, twenty-five miles distant, to the underground mines&apos; tailings fill plants at the Leonard Anselmo, and Mt. Con Mines. Now, with the installation of the new Weed Concentrator in Butte, tailings is delivered by pipeline to a cyclone at the Kelley Shaft, and stope filling has become more highly automated and streamlined. Presently, mill tailings at approximately thirty percent solids by weight, is pumped from the concentrator, eight thousand feet horizontally and upward, to the Kelley Fill Plant, where they are dewatered and deslimed by three Krebs Model D20B Cyclones, which discharge the material into the cased and grouted mine delivery bore holes at desired densities up to seventy percent solids. The vertical boreholes and four-inch rubber lined Victaulic pipe carry the material downward to horizontal distribution lines, which in turn tap into the stops-filling, three inch, unlined steel Victaulic pipelines. The slurry may travel several thousand feet before it finally discharges into the stope, where it lends support to the mined-out area.

Jan 1, 1969