Search Documents

By James C. Barker

Alaska?s known mineral endowment includes some of the largest and highest grade deposits of various metals, including gold, copper and zinc. Recently, Alaska has also been active in the worldwide search for sources of rare earth elements (REE) to replace exports now being limitedby China. Driven by limited supply of the rare earths, combined with their increasing use in new ?green? energy, lighting, transportation, and many other technological applications, the rare earth metals neodymium, europium and, in particular, the heavy rare earth elements terbium, dysprosium and yttrium are forecast to soon be in critical short supply (U.S. Department of Energy, 2010). The REE, accompanied by other high field strength metals (such as Nb, Zr, Ti, Th, W), are associated with alkaline complexes of the Hogatza Belt in northwest Alaska; peraluminous tin-granites of the Ruby batholith in central Alaska and the Porcupine plateau in the northeast; and peralkaline intrusive complexes in the southwest Alaska Range west of Anchorage, and on Prince of Wales Island in southeastern Alaska. Limited evidence suggests that the heavy REE are associated with deposits that became more highly evolved by late hydrothermal processes.

Jan 1, 2012

By R. M. Kleine

In the fall of 1968, Sheridan Geophysics leased the Renzy Mine property 50 miles northwest of the town of Maniwaki, Quebec. A 500-tpd flotation mill was dismantled at Belleterre, Quebec, trucked into the mine over a winter road and re-erected during extreme winter conditions. Approximately one billion gallons of water were removed from Renzy lake to expose the orebody. A 3,000-hp diesel generating plant and a self-supporting community were set up during the early part of 1969. This was a remark-able achievement considering that most of the work, including the pouring of foundations and the draining of the lake, had to be done during the winter months. Despite this, the project was completed ahead of schedule and one million dollars below budget. The mill is now treating an average of 800 tpd.

Jan 1, 1970

By C. E. Cairnes

The Slocan mining camp in Kootenay district; British Columbia; has long been noted for the great number of its silver-bearing deposits; and for the success that has; in many instances; attended their development. The orebearing area lies east of Slocan lake and mainly within a radius of 6 to 8 miles of the mining town of Sandon. Within this limited area 135 or more properties have shipped ore in quantities of from 100 tons or less to more than 500; 000 tons; and with a total value in silver; lead; and zinc ranging from a few hundred dollars to well over $10; 000; 000. Of the three metals; silver has easily ranked first in value; with lead second and zinc third. Zinc production; however; made slow progress in the early years; and with . the exception of the Lucky Jim mine; and a few others where high-grade ore could be readily hand-sorted; was a detriment to the silver-lead ores until improved methods of separation enabled it to take an important place in the mineral production of the Slocan.

Jan 1, 1954

By R Marchant, D Willingham

"Predictive maintenance (also known as PHM or equipment ‘health monitoring’) refers to the intelligent monitoring of equipment to avoid future equipment failures. In contrast to conventional preventive maintenance, the maintenance schedule is not determined by a prescribed timeline; instead, it is determined by analytic algorithms, such as machine learning, using data collected from equipment sensors and/or via simulation.Predictive maintenance offers the following benefits for operators and equipment manufacturers:reduction of equipment downtime by identifying issues before failure, thereby enabling convenient scheduling of equipment service and extending equipment lifetimeautomatic determination of the root cause of the failure, enabling appropriate service to be performed without utilising resources to determine a diagnosis avoidance of costs of unnecessary maintenance and unexpected failures improved safety and product quality.Algorithms and data are critical to predictive maintenance success. Sensor data preprocessing is performed using advanced statistical and signal processing techniques. In the case that data isn’t available for the full range of operating modes, operating scenarios can be simulated. Machine learning techniques are then used to estimate equipment health. Once tested, predictive maintenance algorithms may be operationalised in an IT environment such as a server or cloud. Alternatively, algorithms may be implemented in an embedded system directly on the equipment, allowing for faster response times and significantly reducing the amount of data sent over the network.In this paper, we use both historical and simulated data of the plant under various modes of operation including run to failure, and we then leverage machine learning techniques in MATLAB to estimate degradation and remaining useful life. This technique, of combining both simulation models and machine learning, in the areas of predictive maintenance and equipment health monitoring has been adopted by Safran, makers of aircraft jet engines, since 2007. They now have over 160 modules developed (Lacaille and Aurelie, 2015).Citation:Willingham, D and Marchant, R, 2016. Predictive Maintenance Using Simulation and Machine Learning, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 279–284 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By Glenn A. Squibb

An example of market development is described. The market in rail-lake movement of coal is vital to a rail carrier because of its location. This market is threatened by nuclear and other competing fuel sources and by depressed all-rail unit train rates, The first step to develop the rail-lake transportation market consists of rate adjustments and tariff changes to force tighter scheduling of mines, railroad, port and boats, and thus reduce cost. The second step provides a surge pile at the port to eliminate most of the seasonal disadvantage of rail-lake movement and reduce car detention at the port to almost zero.

Jan 1, 1966

The design/optimization of the pump and cyclones to maximize grinding circuit efficiency first requires a concise understanding of, and clearly defined specifications for, desired grinding circuit performance. Subsequently, the pump and cyclone performances that provide the desired grinding circuit performance can be defined. Once the performance requirements of each process unit are determined, selection of physical equipment parameters that will deliver those performances can be carried out. The Functional Performance Equation shows that there are two distinct efficiencies in closed circuit ball milling. One of these, ?Circuit Classification System Efficiency? (CSE), is the fraction of ?coarse? material inside the ball mill upon which grinding energy is deliberately expended, versus the remaining fraction of ?fines? or finished size material inside the mill, upon which grinding energy is wasted (on over-grinding). The role of the pump and cyclones is to maximize CSE, which is the desired grinding circuit performance. The obtainable, target CSE for any given circuit can be estimated, for example by referring to a plant data base of CSE?s. Design/optimization guidelines then allow us to specify the pump and cyclone performances that will achieve the target CSE. This paper outlines the step-by-step, systematic method of pump and cyclone selection which maximizes CSE. Numerous examples of its successful application are provided.

Jan 1, 2011

By Fred P. Giese

Southeastern reserves of titanium ores are large, widespread, and ample for anticipated demand. The leading titanium industries are mining and beneficiating sand deposits, principally in Florida, and manufacturing titanium pigments. Most of the mineral output is consumed by the producers themselves. In 1962, 20 percent of the national pigment capacity was in the Southeast.

Jan 1, 1964

By R. W. Bartlett

A two step process for treating platinum group metal flotation concentrates Is described while experimental results. The process was designed to be simple and Inexpensive While yielding a high recovery and fast turnaround. Ii consists of electric furnace smelting of concentrate to remove gangue and produce a homogeneous sulfide matte containing all of the base metals and platinum group metals. Sulfide oxidation Is minimized during smelting to avoid Installing an acid plant In the second step, matte Is pressure-leached with oxygen In an acid sulfate system to dissolve Iron, nickel, ?and copper while leaving a residue highly concentrated In precious metals, and typically about 1% of the flotation concentrate mass, A batch process with oxygen titration against the base metal composition of the feed Is used to control the end point of the leach. Sulfides must be eliminated while minimizing the precipitation of hydrolysis products. The leach residue can be smelled to bullion to facilitate sampling accuracy.

Jan 1, 1989

By A. S. Macfarlane

Over the last few years, and especially the last few months, issues relating to Corporate Governance in industry in general, and the Minerals industry in particular, have become increasingly topical, as a result of a number of scandals and failures. The development of International and National Codes for the reporting of Mineral Resources and Reserves began some years ago, and has been followed by more stringent Listing Rules for the Securities Exchanges, as well as more standardised formats and protocols for financial reporting of assets and activities. More recently, some countries have adopted Codes for the Valuation of Mineral Properties, which have focussed on standardisation of valuation approaches to be adopted, and the qualifications of people deemed competent to sign off such valuations. This process has not been without criticism, the main criticism being the proliferation of local standards and regulations, which are often difficult to apply and regulate, or which are too prescriptive for multinational mining companies to deal with. In South Africa, these concerns have been recognised, while at the same time a need has been identified to establish a Code which could be applied to South Africa, and the African continent as a whole. Such a development would necessitate that the Code satisfies the needs of the continent, but in a global context. This global context has already been set by the activities of the International Organisation of Securities Commissions, the International Valuations Standards Committee and the International Accounting Standards Board. This paper explains the progress and process that has been established in South Africa for this purpose, and highlights the key issues which are open to public debate, so that the process is inclusive and transparent, whilst at the same time it is consistent with international time frames, and provides a deliverable product that meets the desired objectives.

Jan 1, 2004

Exploration for SX-EW copper deposits and plant operation depend largely on the copper and gangue mineralogy inasmuch as? they govern the feasibility of leaching. Mineralogical parameters are pivotal in identifying if an ore is suitable to dump, heap, thin layer, vat or agitated leaching and/or if the ore requires curing, bioleaching or alternate lixiviants. Problems in metallurgical testing, production leaching and recovery forecasting are very often related to lack of mineralogical data. This presentation will illustrate the use of quantitative mineralogical analysis for exploration, acquisition assessment and optimization of copper leach operations.

Jan 1, 1996

By Syd S. Peng

Introduction The most commonly used ground control design in coal mining is the determination of pillar size by various pillar strength formulae for mine layout (Bieniawski, 1983; Holland, 1973; Hustrulid, 1976; Obert and Duvall 1967; Wilson and Ashwin, 1972). However, there have been few documented case histories concerning the validity of those strength formulae. Recently there are indications that those strength formulae tend to overdesign considerably. From a safety point of view, there is nothing wrong with overdesign. But an overdesign with large chain pillars reduces the flexibility of machine movement and decreases production. It also reduces coal recovery and, thus, shortens the reserve's life. This is especially true for small operators who own a limited reserve. Those small mines, through past practices or out of necessity, experiment with smaller pillars than those predicted by the strength formulae. Conclusive ev¬idence has been collected that points to the need of a new concept of coal pillar design. Two case studies will be cited to illustrate this point. 3-D US pillar strength formulae Figure 1 shows a sectional layout of a one-unit mine. The seam was about 1.3 m (50 in.) thick with a uniform cover of 64 m (210 ft). A house was located near the center of the section. The homeowner demanded that no surface subsidence and domestic well dewatering should ever be allowed as a result of underground room-and-pillar mining. Physical properties - strength and Young's modulus - of the rock strata including coal were obtained by testing small samples in the laboratory. The uniaxial compressive strength of the coal was 3660 kPa (823 psi). Using various pillar strength formulae, the homeowner recommended that square chain pillars be at least 11 m (35 ft) wide. The coal company, however, desired to pursue optimum coal recovery in the safest and most economical manner. They engaged in three-dimensional finite element analysis of the section taking into account the complete stratigraphic sequence of the overburden. Results indicated that the section can be developed by 5.5 m (18 ft) wide entries at 21 m (70 ft) center-to-center. In retreat, the pillars can be splitted along both centerlines leaving a stump pillar of 5.5 m (18 ft) square at each of the four corners. The 5.5 m (18 ft) square stump pillars still maintained a safety factor of 1.5, although the safety factors calculated by various pillar strength

Jan 11, 1986

By L. C. Brichta

During a study of the Badger-Peacock area from October 1950 to June 1953, the Federal Geological Survey and the Federal Bureau of Mines completed nearly 98 miles of resistivity profiling and drilled 96 test holes aggregating 17,628 feet of bore, In addition, seismic profile measurements were made along 8 traverse lines for an aggregate length of about 16,600 feet. The geophysical surveys were conducted by the Geophysics Branch of the Geological Survey; the drilling was done by the Bureau of Mines. Electrical-resistivity measurements disclosed 21 low-resistivity anomalies and 1 high-resistivity anomaly. Correlation of the resistivity data with the geological information revealed by the drilling disclosed that the low-resistivity anomalies indicated either slumped shale deposits in limestone sinks or undisturbed deposits of shale lying in erosional depressions in the limestone. The high-resistivity anomaly indicated hard, undisturbed limestone at or near the surface.

Jan 1, 1958

By W. A. Padgham, J. A. Brophy

About 85 % of the 350 tonnes of gold produced by 25 mines in the onhwe t Territories (NWT) since 1935 has come from the Yellowknife-area mines, Con and Giant , which exploit shear zones in Archean mafic volcanic of the Slave Structural Province. Four percent of the total production has been from Archean iron formation-hosted depo its, mainly from Lupin Mine, which today produces more gold than Con and Giant combined and has been primarily responsible for the increase of WT gold output from 5 to 12 tonne per year since 1981. The remaining gold ha been won from the following deposit typesall but the last being in Archean rock : sedimentary-volcanic contact depo its uch a Discovery and Salmita (10 %); turbidite-hosted quartz-vein depo its uch a Camlaren and Ptarmigan (1%); Proterozoic deposits such as Shear Lake and Fox (1#) . All but I% of WT gold has come from the Archean Slave Structural Pro ince, which is also the premiere exploration area for gold deposit types that have yet to be productive in the NWT. These types include stratabound gold in mafic and in felsic volcanic rocks (eg. , at Indin Lake and Courageous Lake, respectively) as well as gold in plutonic rocks (eg. Anialik Gnei Complex). Deposits similar to those in the Slave have al o been found in the Archean Ennadai Belt of the Churchill Structural Province. In the Cordillera. there is potential for placer gold and for gold associated with Cretaceou intrusions.

Jan 1, 1986

By Stanley N. Watowich

Recently the petroleum market has made us aware that we are indeed global natural resource consumers, and as such, we have become captive to fundamental global resource economics and their attendant vagaries. Global resource supply problems are as old as civilization and mineral exploration one of its important catalysts. On the basis of natural resources empires have been expanded and new frontiers have been developed. Global consumption and production might even be viewed idealistically as a system dedicated to optimizing distribution to the consumer. However, this is not the case. Political instability and increased government polarization make dependency on a global market somewhat insecure. The U.S. must evaluate its domestic mineral re- sources on the basis that all metals are critical and that dependency on even the common and base metals may ultimately weaken our domestic economy and our potential international relationships and could cause critical weaknesses as demonstrated by the petroleum problem. This paper evaluates specifically the Duluth Gabbro Complex, of Northeastern Minnesota, (figure l), as a potential resource of critical and strategic metals. First, a chronology of some of the early exploration, will be followed by more recent intensive company studies and preliminary evaluations of economic feasibility. Lastly, metallurgical data, on some optimum conceptual mining plans will allow metal production data to be compared with an estimate of U.S. domestic needs in 1990. The purpose of this paper is to put into focus the difficulty of converting resources into vitally needed reserves.

Jan 1, 1981

By Todd Minoski, KRISTIN FLOYD, Michael Murphy, VASU GANGRADE, Gamal Rashed, DYKE MARK VAN, Brent Slaker

Underground stone mines frequently operate on multiple mining horizons or are required to undermine or overmine old workings. In these situations, the effects of pillar columnization and interburden thickness on the stresses surrounding mine workings are poorly understood. Many old workings were not designed to consider the effect on future undermining or overmining and, as a result, are laid out on irregular patterns and with pillar sizes that are difficult or impossible to replicate on adjacent levels. Additionally, as depth increases, even a consistent gridded mine layout may result in poor columnization due to the need to increase pillar sizes. Rules of thumb and past practice for designing multiple levels may often be effective. This paper explores the effect that multiple-level stone mining has on stress redistribution through the discussion of two case-study mines and associated numerical modeling to provide additional insight into situations which may cause concern.

By Charles J. Johnson

The United States is totally dependent on imports for all primary chromite and most ferrochrome supplies. Although the United States imports chromite and ferrochrome from a number of countries, the long-term future of chromite supplies appears to lie in southern Africa (Republic of South Africa and Zimbabwe) where 88 percent of known world reserves exist. Floreover, low mining costs and the availability of low-cost electricity for ferrochrome production gives South Africa a comparative advantage over most other chromite and ferrochrome-producing nations. A well-known problem faced by the United States is that when viewed from a longer-term perspective, the major sources of supply of metallurgical grade chromite and ferrochrome may be subject to disruption. The three countries that have caused the greatest concern have been the Republic of South Africa, the Soviet Union, and Zimbabwe. South Africa presents a particularly difficult problem because it may be subject to internal political unrest and/or U. N, economic sanctions. South Africa has increased its share of world chromium production from about 30 percent in 1968 to 62 percent in 1978.1

Jan 1, 1982

The undeniable fact of life in the next 25 years will be the increasing difficulty of the physical conditions of Australian orebodies facing future miners. We are all familiar with names such as the 3000 orebody at Mt Isa, Hilton, Century, Macarthur River, Cannington, and Ernest Henry. These projects represent a significant. proportion of the planned underground mine development in Australia. Moreover, many of these new orebodies are an order of magnitude more difficult to mine and process than their predecessors. Extraction will be from deeper and potentially more hazardous working environments. Occupational health and safety considerations will place unprecedented demands upon mine operators and technology providers of the future.

Jan 1, 1994

By L. F. Bishop

THE ore bodies of the Butte district1 are found in many different vein systems having many different structural characteristics; some are narrow with self-supporting ore but with weak walls; some are wide with weak or strong ore and weak walls; some of the veins dip steeply and others do not; some have well defined walls, and others, in the "horsetail" area, are mined to sample limits. Consequently, many types of stoping methods are used in mining these ores. The stoping methods used in the Anaconda Copper Mining Company's properties are the square-set and cut-and-fill. The square-set method is the principal stoping method used because, generally speaking, the ore and walls are weak, the ore is high grade, and good extraction is required. These square-set stopes may be classified as conventional, vertical slice, slot, timber rill, and Mitchell slice types. The conventional type square-sets are those of various shapes and sizes, mined by horizontal slicing to the boundaries of the stopes. The rock is slid to the chute and the filling is moved by gravity. The ore and waste may be handled with a scraper when local conditions require it. The vertical-slice square-set system is the type used in narrow veins that are mined in vertical panels. The slot stopes are stopes in wide veins that employ a slot across the vein instead of a con- ventional chute to handle the ore. The timber rill fs a type of square set in which the ore is mined as in inclined cut and fill but the square-set timber is used. The Mitchell slice is the type used for some broken or heavy ore blocks, or for pillar extraction between two converging slot stopes. The cut-and-fill method is used where the ore will stand without much support although the walls may be weak. The principal type of this method is the horizontal cut-and-fill, with mechanical scraping. The inclined cut-and-fill, or rill, stopes are used in some veins too narrow for scraping. The production from the various meth: ods in use for the second six months of 1944 are shown in Table I. [ ] This paper deals mainly with the vertical slice and slot types of square-set stoping, because of their effect on production locally and their potential possibilities here and in other districts, with sufficient reference to conventional square-setting for comparison.

Jan 1, 1945

1. Domestic Production and Use: In 1977, 12 companies operated 31 primary aluminum reduction plants, with 3 firms accounting for 65% of production capacity. Washington, Oregon, and Montana accounted for 31% of the total capacity; Gulf Coast States 23%, Northern States 26%, and other Southern States 20%. Based on estimated producer prices output of primary metal in 1977 Has valued at $4.6 billion. Aluminum consumption by 25,000 firms was centered 'in the East Central United States. Of aluminum consuming industries in 1977, building accounted for about 25%; packaging 22%; transportation 21%; electrical 11%; consumer durables 9%; and other uses, 12%.

Jan 1, 1978

By Clayton M. Rumsey

The U.S. Bureau of Mines investigated prospects and mineralized areas in and adjacent to the Indian Pass and Picacho Peak study areas in 1983 and 1984. The Indian Pass study area contains 33,640 acres and the Picacho Peak study area contains 5,450 acres. The study areas are located in the southeast corner of California and are underlain by Precambrian gneiss, Pre-Tertiary metavolcanic and metasedimentary rocks, and Tertiary volcanic and non-marine clastic rocks. Low-grade gold-silver resources may be present in hydrothermally altered gneiss in the upper plate and altered schist in the lower plate of the Chocolate Mountain thrust fault. The thrust fault is exposed in the study areas for about 3.5 miles west and 5 miles east of Indian Pass. Mineralized zones in the thrust plates were not discovered until 1983. Earlier prospecting explored areas containing minor copper carbonate occurrences in schist and sedimentary and volcanic rocks that are younger than the thrust. Twenty-three mines, prospects, and mineral occurrences inside the study areas and fourteen outs; de were examined for this study. These surficial copper occurrences have been prospected extensively in the study areas; large areas have been scraped, pitted, and trenched by bulldozers. However, they appear to be of limited economic significance. Slightly mineralized zones are in the northwest part of the Indian Pass study area where granite contacts sedimentary and volcanic rocks.

Jan 1, 1986