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The Estonia Mine, operated by Eesti Energia Kaevandused AS (EEK), the mining division of the Estonian Government's energy company, Eesti Energia AS, is a large room and pillar mine located in Eastern Estonia. It supplied approximately 4.9 Mt/a of oil shale in financial year ending 2010, which is used for electricity and shale oil generation. Due to the Estonian climate and the power station's need for a dry product, Estonia Mine has developed a planning system where short-term demands of the power stations dictate the schedule. Such an arrangement requires maximising flexibility and consequently the mine only operated for 199 days in 2010.The footprint plays a key role in achieving mass mining rates as the 12 km + 12 km lease area allows the mine to split into mining districts that act independently of each other and maximise the number of work areas available. Coupled with this, the geology of the mine is relatively homogenous over the mining lease, simplifying the mine design and production methods.During the last five years, EEK has commissioned a comprehensive conveyor network. Consequently, material handling only requires loaders to dump oil shale direct from the production face onto a chain conveyor that feeds the conveyor network that ultimately supplies the enrichment plant. Dewatering is also of critical importance, with 90 Mm3 of water discharged annually. EEK uses large trenches up to 3.5 m deep and 1.2 m wide to channel groundwater. Track mounted mechanical saws are used to cut slots in the floor, to control overbreak in blasting these trenches.EEK has introduced Salzgitter Machinenbau GB 280S auger drills that drill three 280 mm diameter holes simultaneously. This has improved void hole drilling times and reduced the drilling required for each face, reducing the overall production cycle time. Blasting activities have also been decoupled from other mining activities negating the need for firing times through the use of small independent firings, required to control vibrations.

Dec 6, 2010

By A. D. Thomas

Some years ago, the authors developed an analysis of non-Newtonian pipe flow based on enhanced turbulent microscale and associated sublayer thickening. This analysis, which can be used for various rheologic modelling equations, has in the past been applied to smooth-walled pipes. The present paper extends the analysis to rough walls, using the popular Bingham plastic equation as a representative rheological behaviour in order to prepare friction-factor plots for comparison with measured results. The conditions for laminar-turbulent transition for both smooth and rough walls are also considered, and comparisons are made with earlier correlations and with experimental data.

Jan 1, 2007

By Jeremy G. Kress

We propose the discrete element method (DEM) as a complimentary alternative to analytical solutions and FEM models for the analysis of pile response. DEM is a novel approach to the engineering design of deep foundations which can be used to provide insight into the mechanics of soil-soil and soil-structure interaction. It is common to use analytical, empirical, and semi-empirical methods to predict pile behavior, where if granular properties, pile length, or load orientation change, then significant adjustments are made in the design sequence. DEM provides a more uniform approach in granular soils. Based on constitutive force-displacement relationships and laws of motion in rigid and elastic bodies, few changes must be made for a wide variety grain types, pile types, embedment, and load orientation. Preliminary results for simulation of a single pile are qualitatively consistent with results from conventional design procedures and also provide significant information not available from other analyses (e.g., local information about interface failure during shear). Importantly, these analyses are portable to a variety of pile types and installation procedures, which may not be the case for empirical approaches. Given consistent increases in computing power and rapid advances in model speed and sophistication, the DEM should prove to be a robust method for design and the analysis of pile response in granular soils.

Jan 1, 2010

By William G. Fischer

Basic laboratory tests initiated the. Rock Mechanics program. The stress-strain curve, modulus of elasticity, Poisson's ratio, the uniaxial rock strengths, Mohr's envelope, the stress at failure, and creep were investigated. A series of underground problems were then approached using this information; and various field measuring devices, most of which were developed by the Bureau of Mines. Initially, stress concentrations near mine openings were evaluated using the stress relief technique. This required an accurate determination of the pre-mining stress field. Later, stress concentrations associated with the cave line .sere studied. After about thirty stress reliefs over an appropriate time interval the effects of one type of mining could be compared against another. The microseismic technique was used to investigate a possible application of warning devices near the cave line. A study of mane reorientation was made Problems related to the shape and size of pillars and barriers were studied. Partial extraction mining systems were evaluated. The effectiveness of roof bolting patterns were examined. Control of roof stresses was attempted. A new system of mining in heavy ground has been developed using the information secured in the Rock Mechanics program without this system, mining in more than one instance would Nave been next to impossible. Indeed; from this one discovery alone, the Rock Mechanics program has paid off in improved safety as well as in dollars.

Jan 1, 1964

The National Institute for Occupational Safety and Health (NIOSH), in partnership with stakeholders in the mining and surface drilling industries, con-ducted research to develop engineering control technologies that reduce workplace noise exposure. The result of this research partnership is the development of a partial cab.

Jan 8, 2007

By T Trott, M Lewis, G Lumley

The analysis of equipment trends in The AusIMMÆs revision of Monograph 19 - Australasian Mining and Metallurgical Operating Practices (AMMOP) (in prep) in the paper by Graham Lumley raised some interesting, and in parts disturbing, trends in the Australian open cut mining industry. According to the Australian Bureau of Statistics (2011) the productivity of the whole mining industry is down by 34 per cent since 2001. In terms of open cut equipment, median output for draglines is down by 15 per cent since 2003, electric rope shovels are down by 41 per cent since 2003, hydraulic excavators are down by 39 per cent since 2008, front-end loaders are down by 39 per cent since 2007 and trucks are down by 41 per cent since 2006. Clearly e boom has not been good for the efficiency of the mines. During this same time, best practice (defined as the average of the top ten per cent by annual output per unit of input) has declined, but not by as much as the median (eg shovels down by eight per cent, excavators down by 19 per cent and FELs down by five per cent). This paper will build on the analysis of AMMOP to understand the differences occurring between median and best practice and identify the factors contributing to the decline in performance. As the industry enters a period of potentially lower prices for commodities and reduced margins, pressure will be brought to bear on mine sites to start moving more with the equipment they have. An understanding of where efficiency has been lost will be a key component in that. The information contained in AMMOP, and the subsequent analysis of that information in papers such as this one, will be crucial to reversing the decline in open cut equipment performance.CITATION:Lumley, G, Trott, T and Lewis, M, 2012. Reversing the trend in open pit mining equipment output, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 75-82 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

By R. Lindsay Mundell

In the first half of 1990, lessening of cold war tensions was welcome. But Iraq's invasion of Kuwait in August led to the Persian Gulf War in January and February 1991. The subsequent oil shock contributed to a dampening of the U.S. economy, and the U.S. gross national product rose only 0.9 % to $5,463 billion (U.S. billion = 109). The buildup of military forces in the Persian Gulf area focused greater attention not only on petroleum but also on other strategic materials. The U.S. Department of Defense continued to review stockpile goals and upgrade several mineral materials. In addition, the U.S. Bureau of Mines continued to maintain the standby Emergency Minerals Administration. After the Defense Production Act, which authorizes priorities, allocations, and supply expansion, lapsed on October 20, 1990, the Selective Service Act of 1967 became the authority to ensure that orders of the Armed Forces and defense atomic energy programs were given priority treatment.

Jan 1, 1993

By Thomas J. Wright

The evaluation and development of the Eastern North Carolina phosphate deposit resulted in one of the world's largest and most modern phosphate mines and fertilizer complexes at an investment in excess of $90,000,000. The resulting ore beneficiation process showed excellent correlation with pilot plant data. A number of variations from current industrial practices were introduced and projected from bench scale tests through pilot plant to production. Principal among these variations were the following: 1) removal of magnesium by classification, 2) simultaneous flotation of coarse and fine phosphate, 3) the use of saponified fatty acid, 4) utilization of filter wash water for deoiling, 5) utilization of a rougher concentrate for acidulation, 6) calcination of flotation concentrates, and 7) elimination of grinding prior to the manufacture of phosphoric acid.

Jan 1, 1971

By Elizabeth M. Smith

The kcICON design-build project in Kansas City, Missouri includes widening the existing roadway, improving interchanges and grade separation bridges, and replacing the Missouri River Bridge. The Missouri Department of Transportation (MoDOT) typically utilizes steel H-piles and steel pipe piles as driven pile support for bridges. After bidding the kcICON project, the cost of steel rose significantly and the design-build contractor used an innovative approach to reduce foundation costs without significantly affecting the project schedule. The kcICON team conducted a value engineering evaluation of alternative foundation types for use at four grade separation structures. The result of the value engineering evaluation was selection of precast, pre-stressed concrete (PPC) piles as the preferred foundation alternative. Terracon developed a test program to evaluate the performance, capacity, and suitability of PPC piles at the site using a PDA and CAPWAP analyses. This paper presents the value engineering design, rationale for selection of PPC piles, results of the pile test program, and findings during production pile driving. The collaborative approach to the project by MoDOT and the kcICON team, combined with testing and a site-specific design approach, resulted in substantial savings for the design-build contractor.

Jan 1, 2009

By G. Folmo

Allis Mineral Systems' GRATE-CAR agglomeration/induration/reduction process is currently being operated to process ilmenite at Tinfos Titan & Iron KS in Tyssedal, Norway. In this process, balled ilmenite concentrate is fed to a traveling grate where pellets are dried and preheated, using fully oxidized kiln exhaust gas. Hot preheated, semi-indurated pellets are fed directly to a ported kiln where reduction of the ilmenite's iron oxide fraction occurs in the presence of lump coal. The reduced pellet sand coal char are discharged from the kiln to an indirect rotary drum cooler. Cooled pellets and char are screened and magnetically separated prior to their further processing in a downstream smelting operation. The pellets are melted and the titanium dioxide and iron are separated. Operation commenced in late 1986.

Jan 1, 1992

By S Brochot

In cases where coarse gold is present in a deposit, it is usual to use the screen fire assay (SFA) method to analyse the samples. There is no doubt that this method is more accurate than the standard fire assay (FA) and reduces the risk to have a systematic bias. Nevertheless, the difference between the analytical errors of both methods can be glossed over when the overall sampling error is added to obtain the measurement error. In that case, the advantage of the SFA cannot justify its higher cost.The current paper attempts to address this question in the case of a gold ore deposit with visible coarse gold in various sampling situations (drill core sampling in exploration, blasthole or chip sampling in mining exploitation). The overall measurement error is estimated taking into account the analytical error and all the sampling error components following the Pierre GyÆs theory of sampling.Firstly, only the last sampling stage is considered when the pulverised sample is processed either to obtain one analysis sample for a FA or to be screened and subsampled for a SFA. The calculated measurement error clearly shows the advantage of the SFA specifically in presence of coarse gold. Secondly, the half core sampling is studied to explain the observed discrepancies when controlling the second half core. Finally, the blasthole sampling is treated using in situ heterogeneity models to show that the relative advantage of the SFA is hidden by the large overall sampling error.In conclusion, the choice of the assaying method is discussed at the light of the overall measurement error and in accordance to the analysis objective.CITATION:Brochot, S, 2012. Standard fire assay or screen fire assay? Application of the overall measurement error approach to choose the most appropriate method, in Proceedings Sampling 2012 , pp 135-142 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 21, 2012

By R. E. Bou Serhal

Many miners are exposed to dangerously high levels of noise on a daily basis. Over the past 15 years, a continually increasing number of occupational hearing loss has been reported from the mining community in the United States, of which, more than 95% is attributed to prolonged noise exposure. Although the noise exposure levels may differ between coal miners and metal and non-metal miners, in the absence of noise control at the source, the solution is the same: use of personal hearing protection devices (HPD). While protecting the miners? hearing it is also essential to no longer hinder their ability to communicate. With access to an advanced HPD that is customized to the miners? ears we are able to combine these two requirements. Using an intra-aural instantly custom molded HPD miners are protected from high levels of noise. The HPD is equipped with wireless capabilities, and contains both a speaker and an In-Ear Microphone (IEM). Therefore, the miners? speech may be captured from inside the ear and transmitted to the remote listener. This IEM signal is relatively noise-free since it is isolated from the background noise. The IEM speech signal, however, is ?boomy? and is missing some high frequency content, making fricative consonants hard to understand. Nonetheless, the IEM speech signal is correlated with the natural speech signal and may be manipulated through statistical techniques to more closely resemble natural speech. By improving the intelligibility and quality of the IEM signal, numerous applications may be enabled. One use of the enhanced IEM signal will be for radio communication. Using wireless radio communication in a noisy mining environment is sometimes the only practical and affordable solution to allow communication between miners equipped with personal hearing protection devices. Traditionally, one of the weaknesses of such wireless radio communication lies in the lack of designating receivers: whether they are the intended receiver or not, all those carrying a radio receiver are subjected to the broadcasted signal. The current work will detail a new concept of a "radio-acoustical virtual environment" where the radio signal will only be received by miners within a given spatial range, such range depending on the user?s vocal effort as well as the ambient and perceived background noise levels.

Aug 1, 2013

By Leon W. Dupuy

Many articles have been written describing peculiar and particular types of drilling. Little correlation has been made between the character of ground to be drilled and sampled and the type of drilling most desirable for procuring satisfactory samples. In development work, the engineer and metallurgist often desire the recovery of a sample in as physically natural a condition as possible, particularly when the sample must provide material for process tests as well as chemical and physical analyses. This paper describes the results of experimentation in drilling unconsolidated materials carrying titanium minerals in the Magnet Cove area, Ark. The drilling was most difficult in that the ground varied much in consistency, and it was vitally necessary to recover a physically natural sample. Ordinary churn drilling recovered a sample that could be analyzed chemically, but the sample was not in its natural state. The problem was successfully solved by utilizing and further developing methods used in the oil and clay industries.

Jan 1, 1949

By David R. Hargis, John W. Harshbarger

The Upper Santa Cruz Basin lies in the drainage area of the Santa Cruz River in Arizona, and extends upstream from the community of Rillito to the international boundary [(Fig. 1)]. The principal water use area lies between, and includes, the cities of Tucson and Nogales. A subsurface geologic barrier near Rillito provides a reasonable dividing line between the ground waters of the upper and lower Santa Cruz basins. The upper basin contains the Tucson and Sahuarita-Continental critical ground water areas. The Tucson water use area encompasses the Tucson metropolitan area and extends from the northern boundary of the basin south to the boundary between the Tucson and Sahuarita-Continental critical ground water areas near San Xavier. The San Xavier use area is the San Xavier Indian Reservation. The north and south boundaries of the Continental use area coincide with the limits of the Sahuarita-Continental critical ground water area. The first study of ground water in this valley was initiated by Dr. G. E. P. Smith in 1905, and the results were published in 1910, followed by a series of bulletins of the Arizona Agricultural Experiment Station, University of Arizona, covering the general field of ground water development and utilization. Beginning in 1939, the ground water branch of the US Geologic Survey, in cooperation with the Arizona State Land Department and the Arizona Water Commission (AWC), published a series of bulletins concerning ground water occurrence and utilization in various areas of the state. In 1975 and 1977, the AWC published the Arizona State Water Plan (Arizona Water Commission, 1975) comprising a detailed inventory of water availability and use in Arizona and a study of alternative futures. The importance of ground water supplies in the Upper Santa Cruz Valley cannot be overemphasized. Metropolitan Tucson, surrounding agricultural areas, and the mineral industry are completely dependent upon ground water. Agriculture has been the largest user of ground water. The land distribution of the Upper Santa Cruz Basin is rural in character with large tracts of land included in national monuments and national forests. The Upper Santa Cruz is one of several state basins that does not depend upon one single industry as its major economic activity. Agriculture, mining, tourism, international commerce, and manufacturing all contribute to a viable economy. The city of Nogales, on the Mexican border, and the city of Tucson, to the North, are the centers of commerce in the basin.

Jan 1, 1982

By Joseph M. Singer

This research project had two main objectives: (1) To identify the smoke limits of gaseous fuel-air mixtures and (2) to obtain and evaluate basic chemical information on the formation of smoke in very rich flames near the smoke limit. Such information would do much to establish the circumstances for car-bon deposition in gas appliances and in other types of combustors. Based on tests with ethylene and propane, these studies showed the following: 1. Smoke limits are related to the yellow-tip limits of the fuel. Previous research established sufficient data to permit prediction of yellow-tip limits on gas burners using a wide variety of fuels. The present study of smoke limits deals only with ethylene-air flames, but the concept that was developed is probably applicable to other fuels.

Jan 1, 1962

By Ramon S. Pizarro

The Masbate Province, Philippines, has been a gold producer for many years. Several gold properties were profitably operating until the outbreak of World War II in 1941. One of these properties was the Masbate Consolidated Mining Company that at the time showed an impressive production rate of more than 4,000 metric tons of ore per day and one of the lowest milling costs on record in the country at that time. Interesting enough, t was the milling equipment left abandoned at Masbate that gave birth to one of the giant copper producers in ASIA. In 1955, Atlas Consolidated Mining and Development Corporation started a new operation at its copper property in Cebu with the seven 2.4m 0 x 3m long (8'0 x 10' long) ball mills left abandoned at the old Masbate Gold Mine. Now, 25 years later, Atlas is processing over 100,000 metric tons of copper ore per day through its three copper concentrators, and, the seven old mills are still grinding, copper ores now.

Jan 1, 1981

By Gustavo Armijo

Slippery and unstable working platforms spoiled not only by natural weather conditions but also by the effects of the construction process (drilling mud, grout slurry) are among the main sources of hazards. Due to this fact a set of recommendations for execution and maintenance of working platforms are presented in this paper, which is based on a study on this subject that is being carried out by AETESS, the Spanish Federation of Geotechnical Contractors. The main objective of this paper is to establish the basis for the right execution and maintenance of working platforms for geotechnical jobs with the idea of increasing safety and productivity. All the aspects involved in working platform safety are analyzed: ground and equipment characteristics, geometric conditions and working platform maintenance. From this analysis a set of general requirements is proposed together with the necessary specific controls before and after the equipment arrival to the job site. In order to facilitate this analysis some flow charts and tables and specific appendixes for each geotechnical technique are included.

Jan 1, 2006

Mineral Changes that Occur During Coal Gasification

Sep 13, 2010

By L. A. Grant

This paper describing the concentrator practice of the Montana Mines Corporation at Helena. Mont., is one of a series of articles on milling methods and costs being prepared by the United States Bureau of Mines. The Spring Hill mine and mill are located 4 miles south and west of Helena, Mont., near the head of Grizzly Gulch. The mine portal is on the east slope of the gulch, and the mill is directly opposite on the west slope. Grizzly Gulch is one of the tyro gulches which unite at the south end of Helena to form Last Chance Gulch, on which the main street of Helena is built.

Jan 1, 1931

By Enrique Levy

The publication from which this paper was abstracted is the first at-tempt to correlate all the metallogenic deta compiled by the author for the preparation of the 1:2,000,000 Metallogenic Map of Central America. It is not a treaty of metallogenic theories but rather a careful effort to postulate metallogenic provinces and epochs with the intention to stimulate other geologists and mining companies familiar with the area to criticize and improve on the ideas proposed. The sole purpose being to find new mineral deposits for the betterment of our people.

Jan 1, 1971