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By André van Wageningen

Long term mine scheduling is one of the most difficult optimization problems. The problem is said to be NP-complete in that the best possible solution cannot be found any quicker than checking all possible permutations and combinations. In current mining operations, it is important to report changes in long term plans as soon and as accurately as possible. Where geological data can change rapidly, such as in narrow vein deposits, the need to quickly identify and optimize different long term alternatives becomes a difficult task and can lead to many permutations of the long term mine plan. The question arises, is the new plan optimal or not? Can the company objectives be met while adhering to operational constraints? Although a number of optimization techniques have been used in the past, many include significant simplifications or fail to produce acceptable results within the required timeframe. Genetic Algorithms (GAs) are among the most promising optimization techniques within operations research. They are based on natural selection and evolution of solutions to complex problems. They have been known to quickly converge within a few percent of the optimal solution by examining only a fraction of the possible permutations. The GA itself contains very little problem specific information and, as such, in this study, has been linked to a discrete-event simulation (DES). The DES is able to evaluate each sequence proposed by the GA and determine the effectiveness and value of each schedule. The DES feeds information regarding the feasibility and quality of the solutions back to the GA during the optimization process. In this paper, GAs and DES are described and the coupling of the two methods is outlined. The GADES module is then used to ?optimize? a narrow vein theoretical case study and the results discussed in a broader mining context.

Oct 1, 2004

MR. RIGG: Gentlemen, I would like to welcome you all to the symposium this morning. My name is Jack Rigg, and I m a special assistant to Hollis Dole, Assistant Secretary of the Interior for Mineral Resources. Hollis is not in town this morning, and I am here to pinch-hit for him. The first order of business this morning is remarks by the Honorable Russell Train, Under Secretary of the Department of Interior. Mr. Train. MR. TRAIN: Thank you, Mr. Rigg. Lest you think that Hollis Dole is not interested in this symposium, let me just say that fie is flying back from Australia just to be here. He is heading up a United States delegation in Australia meeting on resource problems in the Pacific. And I believe he will be here about noon.

Jan 1, 1970

Economic Sustainable Power for Mineral Processing

Sep 13, 2010

By D. Harrington

The number of fatalities from mine explosions for the fiscal year 1945 dropped below that of the year before; continued improvement over the record of the years from 1940 to 1945 is hopeful, but the number of reported explosions has increased rather than diminished, and the number of victims claimed by explosions is often more definitely a factor of chance than forethought. Mine fires and explosions can be eliminated through the methods now well-known to those well-informed in matters pertaining to safety in mining but ignored by many coal-mine operators and employees who follow procedures of the past or their own short cuts, regardless of disasters that may result: Tried and proved safety measures for preventing mine fires and explosions have been recommended to the mining public repeatedly, yet only a relatively small but far-sighted minority have adopted these measures and made them a part of operating practice. That far more explosion disasters did not occur in 1945 is fortunate. In 1945 a coal-mine fire of electrical origin caused heavy loss of life, while several others from the same cause were controlled with but few fatalities; this hazard is now being curbed temporarily to some degree after the bad record of the two preceding years, but a real solution of the problem has not been reached, although cooperating committees trying to produce at least some answer have made progress.

Jan 1, 1946

By C E. J de Ronde, I C. Wright

Oceanic subduction-related volcanic frontal arcs extend over 20 000 km within the western Pacific basin and over 21 500 km worldwide, yet they remain largely unexplored with respect to active seafloor mineralization. Systematic exploration of 26 major submarine volcanoes along ~840 km of the Kermadec arc northeast of New Zealand has documented ten (39 per cent) as being hydrothermally active. This frequency of venting is comparable to that on slow-to-moderate rate spreading mid-ocean ridges, which comprise ~80 per cent of the 60 000 km-long global system of spreading centers. The chemistry of fluids discharged from the Kermadec arc volcanoes is moderated by magmatic components in both the gaseous (CO2 + SO2-H2S) and liquid (Fe) phases at very high concentration.The high frequency of venting coupled with chemically rich discharge discovered during this first systematic survey of any arc system forecasts submarine arcs as being important sources of chemicals to the oceans and as potentially lucrative exploration sites for seafloor mineralization. The exploration protocols developed during these surveys include bathymetric mapping of mostly unknown volcanic edifices, followed by detailed water column profiling and sampling to detect and characterize volcanic fluid emission signatures. These procedures are being refined as the survey progresses, both for efficiency and as direct seafloor observations become available for predictive application of water column plume information to guide seafloor mineral exploration.

Jan 1, 2002

By F. Habashi

The phosphate fertilizer industry is at present based mainly on the use of sulfuric acid. This technology results in the generation of large amounts of radioactive gypsum that represents disposal and environmental problems. Also it involves the use of expensive reactors for acidification that necessitates the frequent replacing the damaged agitators. Applying hydrometallurgical techniques such as in-situ, heap, or vat leaching to phosphate processing could solve these problems. In this case, however, nitric acid must be used and dicalcium phosphate (40% P2O5) may be obtained as a final product. It is insoluble in water but soluble in citric acid and is an excellent fertilizer. This technology does not interfere with uranium recovery if desired. In addition it permits the recovery of rare earths which are otherwise lost in the gypsum.

Jan 1, 2011

By John R. Goode

"This paper reviews options for the separation of a mixture of rare earth elements (REE) into its component elements. Earlier separations used selective chemistry such as double salt precipitation and reductive/oxidative processes – methods that still have a place in the industry. Fractional crystallization was developed for more complete separations of adjacent REE. The latter method was replaced by ion exchange (IX), which was in turn replaced by solvent extraction (SX). Two main SX chemistries are in use, solvation and cation exchangers, with several variants (mixed solvents, ionic liquids, etc.) now under investigation. SX plant configurations have evolved including advanced techniques like “hyperlinking”, novel saponification methods, and alternative stripping techniques. The classic mixer-settler is the most commonly employed device although centrifugal contactors have been pilot-tested. Non-dispersive SX options including microfluidic devices and membrane-assisted SX techniques are being developed and could revolutionize the SX option. Other REE separation techniques now being studied include Molecular Recognition Technology (MRT), Free Flow Electrophoresis (FFE), newer IX systems, and electrolytic processes. Additionally, the classical crystallization and selective precipitation methods and newer bacteria-mediated processes, chloride volatilization, high performance liquid chromatography, and magnetic separation systems have been studied. This paper reviews the options and concludes that conventional SX is the technology of choice but viable alternatives could be demonstrated and acceptable within a couple of years.INTRODUCTIONThe chemical properties of the individual REE are very similar which is why REE minerals and ore deposits almost invariably contain a mixture of all fifteen REE, i.e., La to Lu plus Y. That said, the distribution of REE in a given deposit is frequently dominated by the light REE (LREE, i.e., La to Nd). Examples include the Bayan Obo, Mianning, Lynas Mt. Weld, and Molycorp Mountain Pass deposits where heavy REE (HREE – Sm to Lu and Y) typically account for well under 5% of the REE content. The LREE operations produce some HREE but the main sources of these important elements are the ionic clay deposits of Southern China. Importantly, all of the REE recovery operations referenced above, except for cerianite-bearing ionic clay deposits, initially produce a mixed REE precipitate or calcine with a REE distribution similar to that in the ore (Goode, 2016). However, the consumers of the REE, the manufacturers of magnets, phosphors, catalysts, optical glass, etc., require separated products with purities generally ranging from 99% to as high as 99.9999% depending on the element in question and the end use. Hence there is a need to separate the individual REE one from the other. This paper is intended to review the options."

Jan 1, 2016

Analysis of rock discontinuities, collected using a scanline method, has been undertaken at the Iron Duke open cut mine, on the southern margin of the Middleback Range in the Gawler Craton, South Australia. The iron mineralisation, which is a product of supergene enrichment of carbonate sediments, is located on the W (western) limb of a gently N plunging D2 macrosyncline. Mesofolds plunge shallowly to the NE or steeply to SE, suggesting two shortening events, of which the second produced significant macrofolds. Discontinuities include:faults and shears which display variable orientations, mainly striking WNW dipping steeply N; mesofractures or joints maintaining a well constrained orientation, dipping steeply S, subvertical striking E-W; and bedding surfaces which are folded about a gently N plunging axis. Through this example of the regional control exerted on local discontinuities, it is clear that discontinuities are not randomly distributed as often assumed in purely statistical approaches. Commonly for rocks of any age there is a distinct discontinuity pattern, reflecting the geological deformation history. If the controls exerted on local rock discontinuities can be determined and assigned a number related to their significance, the way forward is available to develop a site specifc knowledge base that can make realistic predictions for any position in a given rock mass. Such a procedure would involve assessment of the regional geology, linked to scanned discontinuities either via manual or automatic means. Recent advances in automatic scanning rock faces (eg by the I-SiTE Laser Radar) to determine discontinuities distributions, enable the rapid calculation of rock characteristics. This is a significant advance in rock engineering, providing a method of safe and quick collection of data. However it creates problems in the presence of an increase in the geotechnical data available, which should be assessed in the context of the regional geology. Although techniques are underway to analyse post-blast discontinuities, the next signifant potential advance in this area could be the integration of a knowledge based system to assess discontinuities ahead of mining, incorporating regional assessment and human intuition.

Jan 1, 2000

By L D. Queen

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Tifalmin porphyry copper district is located in the Star Mountains roughly 35 km north-east of the Ok Tedi mine. The district is a cluster of temporally and geochemically related porphyry copper deposits and their associated skarns. It covers an area of roughly 10 × 6 km and comprises at least three intrusions (Olgal, Futik and Kum Kom) where drilling has demonstrated the presence of porphyry copper mineralisation, and another three intrusions (Rattatat, Unfin and Pad 48) where porphyry copper mineralisation is strongly suggested by surface investigations and geochemical or geophysical signatures.Copper and gold mineralisation was first discovered in the area in the 1960s as part of the regional exploration program by Kennecott that located Ok Tedi. The mineralisation is associated with poly-phase porphyritic diorites, quartz diorites and tonalites that intrude the Upper Eocene to Middle Miocene Darai limestone and underlying Cretaceous to Eocene Feing Group. Radiometric K-Ar and U-Pb zircon ages cluster between 4 and 2 Ma for both the mineralised and post-mineral intrusions. In addition to porphyry-type mineralisation, variable amounts of calc-silicate and/or magnetite skarn occur near the contact of most of the intrusions. Mineralisation in the Olgal and Futik porphyries occurs as chalcopyrite replacement of mafic minerals and in a stockwork of micro-veinlets. Mineralisation mostly occurs in the intrusions but is also observed in hornfelsed siltstones and sandstones of the Feing Group on the southern margin of the Olgal intrusive body. Quartz veining is uncommon. Secondary magnetite is commonly associated with the highest copper and gold grades. Sericitic alteration is most prominent in the mineralised hornfels. Structurally, the area is dominated by syn- to post-mineralisation thrusting from the north. At least one of the deposits (Olgal) appears to be truncated at depth by a thrust fault.CITATION:Queen, L D, 2015. The Tifalmin porphyry copper gold district, Star Mountains, Western Papua New Guinea , in Proceedings PACRIM 2015 Congress, pp 357–360 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By Ross W. Smith

Microflotation and surface chemical studies were conducted on a chromite from the Stillwater Complex in Montana and on some of the minerals usually found to be associated with such chromites. Considering the chromite it was found that aging the ground mineral in air or heating it markedly affected its flotation behavior. Much of the observed effects could be attributed to oxidation reactions involving surface chromium and iron species. Strongly acid pretreating the mineral appeared to reverse such effects. Thus, it can be concluded that the manner in which the mineral (or the ore) is pretreated is of utmost importance in its flotation. Work carried out on associated gangue minerals determined how they are likely to behave in a flotation environment and how certain foreign ions derived from a chromite ore itself can affect their surface characteristics and, thus, presumably also their behavior in a flotation circuit.

Jan 1, 1981

By Ismar Antônio Sardinha

Usually outer straight steel tubes are used to blow supersonic oxygen into LD converters (BOF) to make liquid steel, although conical tubes are used too. Inner tube for oxygen blow and intermediary tube for water IN and water OUT are normally straight steel tubes. Present paper shows the influence of outer tube shape and metal used to in lance cooling and, consequently, a skull retention on lance surface. There are two parameters more important related to lance cooling: velocity of water out and the total lance cooling by addition of thermal conductivity of outer tube metal to it. For this comparison outer tubes are made of carbon steel or copper, and can be straight or conical. As related to velocity of water OUT, outer straight tubes have bigger efficiency than conical tubes. As related to total lance cooling, outer tube metal made of copper has much bigger efficiency than steel because of its thermal conductivity 7 to 12 times more depending on work temperature. The lance cooling has much bigger efficiency for the patented SKULLS3® technology with no skulls on the lance and no skulls into the mouth of LD converters (BOF).

Aug 17, 2017

By John Russell

"Faster, safer, grinding mill relining offers the obvious attractions of reduced mill relining times with the knock-on incentive to reduce all other maintenance down-time, opening the possibility for increased annual plant utilisation.Leading edge liner handler technologies by RME, focused toward even shorter relines for very large SAG and AG mills, have recently split into two quite distinct paths:•,?Single SAG/AG Mill Relining Machines (MRM’s) of very large capacity, such as Newcrest Cadia’s 40’ SAG MRM of 6000 kg capacity and P.T. Freeport’s 38’/34’ SAG MRM of 7250 kg capacity;•,?Twin-machine SAG/AG Mill Relining Systems of moderate to large capacity such as BHP Billiton’s Escondida Laguna Seca 38’ SAG MRM’s, each featuring 4500 kg capacity.RME, its customers noted above and their liner suppliers are providing leadership in this important annual utilisation advance.Once the 24 hour mill shell reline becomes reality, liners designed for maximum profit, not maximum life, albeit exchanged more frequently, become possible too.INTRODUCTIONAt most mineral grinding plants, mill relining activities dictate each maintenance shutdown’s critical path. When annualized, mill relining remains the largest, single influence in defining plant availability.Because of restricted access, both inside and outside the mill, increased application of manual labour has no effect on reducing relining downtime. The only answer for RME has been to develop and apply new relining technologies now known as RME’s Mill Relining System.RME’s primary focus for over twenty years has been the reduction of grinding mill relining times while simultaneously providing a marked improvement in relining safety. Our original (1990) target was to halve traditional (pre-RME) reline times and to eliminate accidents and injury by mechanizing all physical work."

Jan 1, 2008

By Rees J. Llewellyn

High chromium white irons can be formulated to provide required combinations of abrasion and erosion wear resistance, toughness and capability to withstand corrosion attack. As a consequence, they are used widely in casting form throughout the mining/mineral processing industry, particularly as components for slurry pumps and also as mill and crusher liners, laminated wear plates in chutes and hoppers and in valves, nozzles and cyclones. Traditional cast chromium molybdenum and high chromium white irons for wear applications are covered in ASTM A532 Classes 11 and 111 and are also available as comparable proprietary alloys. They rely on heat-treated, hypoeutectic microstructures containing a high volume fraction of very hard eutectic/secondary metal carbides and martensite to provide extremely high wear resistance. The ability to increase the carbide volume fraction and hence achieve higher wear resistance, has been limited because of severe casting difficulties encountered when carbon and chromium contents are raised and hypereutectic alloys with structures also containing coarse acicular primary metal carbides are produced. The limitation has been overcome and cast hypereutectic chromium white iron pump components have established themselves in a wide variety of mineral processing service applications. Comparisons will be made between the microstructures and wear test performance data for the various alloy types and details will be provided of the service performance improvements that have been achieved through the use of hypereutectic chromium white irons.

May 1, 2004

The purpose of the contract was to develop an improved coal mine dust sampler whose electrical-to-mechanical energy conversion efficiency would be superior to that of the presently available equipment. The electrical to (pressure) X (volume) conversion efficiency directly affects the size and weight of the air samplers. At least half of the mass of present equipment is composed of the rechargeable batteries. Any increase in efficiency will allow this mass to be reduced or the flow rote to be increased.

Jan 1, 1974

By Stephen C. Tadolini, Thomas M. Barczak

A critical safety component for all underground mining is intrinsic and standing support systems. Specifically, tabular hardrock mining exploits a wide variety of deposits that require various methodologies to safely mine the ore material. Several new support systems have been developed in recent years for hard rock applications which have been modified or applied in a variety of ground control applications. These include prestressing devices, improved cribs, and free standing supports. Various standing support and prop-type systems have been designed for hardrock applications with seismic loading conditions to accept prestressing. The prestressing, using water-filled cells, creates an active load upon installation and is considered essential to maintain support during and after the blasting of the mine faces. Heavy seismic activity is also present in these mines and the prestressing units can provide some energy absorption capability to help preserve the integrity of the support. This paper presents an overview of these innovations in support technology.

By John E. Tilton

During the past several years — much to the delight of producing firms and countries — copper prices have surged from under $1 to more than $3/lb. Anyone familiar with the industry also knows that since the early 1970s the long-run trend in real copper prices has been significantly downward. This sharp contrast between short-run and long-run trends raises the issue of the forces behind these developments. What has been driving short-run prices up and long-run prices down? Simple economics suggests that it is all a matter of supply and demand. When demand is rising faster than supply, prices will rise and vice versa.

Jan 1, 2006

By K. S. Liddell, L. A. Smith

"Kell is a hydrometallurgical treatment option for the recovery of platinum group metals (PGMs), gold, silver, and base metals from flotation concentrates to refined products on site. The process is cyanidefree, while eliminating emissions of sulphur dioxide, arsenic trioxide, and other toxic species often emitted by smelters and roasters. Kell has been tested on a range of concentrates, including PGMs (UG2, Merensky, Platreef, Great Dyke, Great Lakes, Lake Superior and others), refractory gold-silver, coppergold, and polymetallic concentrates. High extraction efficiencies (>95%) are achieved for value metals (Pt, Pd, Rh, Au, Ag, Ni, Cu, Co) and secondary metals (Sb, Zn, Pb, and others). Studies comparing Kell with smelter-refining show economic benefits: capex 18–33% of smelting; opex 51–66%; electricity consumption 13–46%; and environmental benefits: greenhouse gas emissions 57–61% of smelting, acidification 5–27%, human toxicity 37–62%, and freshwater ecotoxicity 43–55% of smelting. Synergies for Kell plants alongside smelter-refineries include utilization of recovered acid from sulphur abatement systems and excess capacity in precious metal refineries. Kell is unconstrained by concentrate grade and impurities, allowing the co-location of Kell plants for treatment of non-smeltable concentrates alongside existing smelters.Kell has been demonstrated in a nine-week integrated pilot campaign at 1:1000 scale, supporting a bankable feasibility study for a 110 000 t/a plant treating a UG2-Merensky concentrate at Pilanesberg Platinum Mine (PPM), owned by Sedibelo Platinum Ltd, which has along with South African Industrial Development Corporation (IDC), invested in Kell. Zimbabwean Mining Development Corporation (ZMDC) has signed a Memorandum of Agreement (MOA) with KellTech for a centralized PGM concentrate processing plant."

Jun 1, 2019

By A. Uiga

The U.S. Bureau of Mines funded a project which addressed objectives concerning irrigation of native plants and inoculation of native plants with vesicular-arbuscular mycorrhizal (VAM) fungi. The specific irrigation objectives were 1) to demonstrate the performance capabilities of solid-set irrigation for reclaimed mineland conditions, and 2) to demonstrate and evaluate three irrigation concepts under two separate water supply conditions. The VAM inoculations were to assess irrigation benefits in establishing VAM relationships for transplanted native species. Following the seasonal demonstration (May to September 1983) at 3 separate mine sites, conclusions were made that apply to the 6 state Western mining industry. The demonstration sites were located in Montana, Wyoming, and New Mexico. Positive conclusions were reached for 1) the use of soil moisture sampling with or without irrigation, and 2) the selection of solid-set sprinklers as the irrigation method. The conclusions about the irrigation concepts and strategy were mixed, due to the short-term (1 season) nature of the project. No conclusions could be reached for the VAM inoculations because the study time was too short.

Jan 1, 1984

By Keith A. Heasley, John L. Ellenberger

The National Institute for Occupational Safety and Health (NIOSH) has continued the research role of the former U. S. Bureau of Mines to develop techniques that will reduce the hazards in the mining work place associated with coal bumps. Current research focuses on both analyzing historical seismic data from bump-prone operations and utilizing a mine-wide seismic network to investigate the exact strata failure mechanics associated with bump-prone geology. The anticipated outcome of this research will be reduced bump incidences through advanced engineering concepts and designs which implement the new understanding of strata behavior. The analysis of the historic seismic data consists of correlating observed mining seismicity with the geologic and geometric parameters at the sites. The primary seismic parameters are the timing, location and magnitude of are corded seismic event. These parameters are correlated with such mining parameters as: the overburden, the size of the immediate gob, the size of the district gob area, etc. This detailed analysis of historical seismic data has provided an informative quantifiable relationship between many of the specific mining parameters and the induced seismicity. The second aspect of the coal bump research is the instrumentation of an appropriate field site to determine the main roof, floor, and gob behavior associated with bump behavior. The chosen field site is a deep-cover longwall mine with competent geology in a historically bump-prone area. The primary field instrumentation is a three-dimensional, full-waveform, seismic array with both surface and underground sensors surrounding an active multi-panel district. The purpose of this seismic array is to determine the timing, the exact location, and the mechanism (tensile fracture, bedding plane slip, etc.) of the failure of the strata surrounding the active and multi-panel gobs. The preliminary results presented in this paper help to define the strata failure areas around the longwall panel.

By J. W. Howland

To determine their effectiveness in different climate and soil conditions, a demonstration of dozer blades specifically designed for recontouring mine spoil was conducted at an East Texas surface coal mine. The specialized equipment included a 48-foot angle blade, a modified 24-foot "U" blade, a 13-foot deep "U" blade, and a 24-foot grading bar. Both the 4b-foot and the 24-foot "U" blades were mounted in a two-tractor, single-operator configuration. To meet flotation problems common in this mining region, a 22-foot lightweight blade was developed and demonstrated for use on a 400-430 hp tractor. The demonstration involved 1,185 acres and showed a 50% reduction in reclamation costs and a 47% reduction in fuel requirements for this mine site over conventional equipment. Improved equipment, trained operators, good supervision, and improved monitoring techniques contributed to the savings. Procedures and results of the demonstration are presented and analyzed here along with guidelines for application of findings.

Jan 1, 1981