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By Benjamin Cebrian

Traditional dilution control systems range from computer modeling, use of physical markers on the field as polypipes to a technology that marks some control points where displacement is measured. The latter includes walking over a muckpile which is prohibited by some mining companies as a safety measure. The new technology presented in this paper is a patented system that is installed on board excavators (backhoe or front shovel types). Several control points are set along ore/waste contacts and their position is uploaded on the corresponding shovel. The operator proceeds on mucking until he is alerted when reaching any of the several control points previously located in the blast patterns and that have moved with the muckpile. A case study is presented at a high grade copper mine, were unique 3D shapes are showing as a result of using an on-board excavator dilution control system. Both ore-loss or dilution cost of opportunities are analyzed.

By Ove Alm

Wet and dry specimens of three rocks of approximately granitic composition were deformed at different experimental conditions. These experiments were carried out in order to study the extent to which water, either added or released from mineral reactions, may affect the mechanical properties and the microstructure of these rocks. The experiments were conducted in a Griggs&apos; hot creep apparatus at temperatures and pressures up to 900ºC and 1000 MPa respectively; and most of them were performed in the constant strain rate mode [(1.10-6 < t < 1 • 10-4 s-1 )]. All three rocks were low porosity rocks, and the wet specimens never contained more than 0.9 wt % of added water. The experimental results are, however, quite unequivocal: They show that wet rocks are weaker than dry ones. A significant difference is even found for rocks tested in uniaxial compression at room temperature. A few experiments carried out on specimens obtained from larger prestressed rock cores indicated that the central parts of these cores were more likely to contain more microcracks than the ends. Optical microscope examinations revealed that extensive microcracking takes place even at the highest temperatures, where other mechanisms such as slip and dislocation creep also become important. Very little partial melting could be observed except for the specimens deformed at 900ºC.

Jan 1, 1982

By D. Yu. Paleev, O. Yu. Lukashov, A. Yu. Krainov, E. R. Shrager, I. M. Vasenin

The gas-dynamic method is presented of calculation of explosion-proof distances during an explosion of the methane-air mixture in mine working. On the basis of this method is modelled of shock waves interaction with explosion protective parachute partitions, obstructions and water barriers. Calculations have been carried out of attenuation factors of shock waves during their interaction with explosion protective structures, arranged near conjugation zones of mine workings. Possibilities have been analysed of suppression of intensity of shock waves and of propagation of shock waves control in mine working network of coal mines by installation of explosion protective structures.

Jan 1, 2003

By V. Koump, T. F. Perzak, R. G. Olsson

Jan 1, 1965

By E K. Leeka

Process control limitations have led to suboptimal performance of the crushing section of Sishen MineÆs Jig Plant. The performance of the PID (proportional-integral-derivative) controller implemented during commissioning was hampered by the relatively small buffer capacity between the crushers and screens. The inability to maintain the tertiary crushing chamber under full choke conditions lead to inefficient crushing and reduced crusher product cubicity.Model predictive control (MPC) was implemented in the tertiary crusher plant in May 2012 and resulted in a throughput improvement of six per cent in its first month. The controller was further optimised and indicated a throughput improvement of 16 per cent during on/off testing in July 2012. The throughput improvement is attributable to the finer crusher product resulting from operating the crusher under full choke conditions and controlled feed rate to the tertiary crusher plant screens. The next step is to couple the model predictive controller, automated gap control system and an economic optimiser to ensure maximised throughput and value from the resource.CITATION:Leeka, E K, 2013. Performance of model predictive control on the crushing circuit at Sishen Mine, in Proceedings Iron Ore 2013 , pp 417-420 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By Sidney Katell

Covering the period from January 1961 through December 1961, this report is a continuation of the series that began with the publication of Information Circular 7516 in October 1949. It is also the third report in the series to be prepared as a cooperative effort by the Bureau of Mines and the American Association of Cost Engineers. The cooperative agreement between the two groups provides for the publication of an annual cost bibliography with the work load involved in the preparation shared equally. The abstracted articles, concerned with all facets of cost engineering in the field of chemical and petroleum plants and related facilities, came from the following sources: 1. A.A.C.E. Bulletin. 2. Bureau of Mines Information Circulars. 3. Bureau of Mines Reports of Investigation. 4. Chemical Engineering. 5. Chemical Engineering Progress. 6. Chemical Week. 7. Coal Age. 8. Coal Utilization. 9. Cost Engineering. 10. Industrial and Engineering Chemistry. 11. Nucleonics 12. Oil and Gas Journal. 13. Petroleum Engineer for Management. 14. Petroleum Refiner. 15. World Oil.

Jan 1, 1962

By S. Fawell, H. R. Manouchehri

The main electrophysical properties, i.e., dielectric constant and electrical conductivity, of pure calcite, quartz and wollastonite mineral samples were measured and their triboelectric charge attributes were investigated by contacting minerals particles with different tribochargers made from different materials. In addition the energetic work function values for mineral samples were estimated due to their acquisition charge. Besides, the behaviour of triboelectrically charged of different particle size fractions of mineral samples were inferred. Finally an attempt were made to translate the findings from single mineral systems to a real carbonate ore. The results exposed good prospects to beneficate the examined minerals by triboelectric separation.

Jan 1, 2002

By J. A. Botín

In modern mining, the core of mine planning and design is the block model, a simplified representation wherein the ore deposit is divided in a number of virtual rock cubes, each characterized by technical and economics parameters. Mining engineers use this model to design the mine and develop production schedules. Traditionally, sustainability issues are not considered in the mine design, planning and engineering processes but rather are incorporated in the later stages of the feasibility evaluation as necessary expenditures and operating costs. This paper describes the results of a research project aiming to develop a methodology to incorporate sustainability parameters directly into the block model, so that they become an integral part of the design, planning and scheduling processes. It is considered that the incorporation of sustainable parameters into the block model would yield a more responsible mine design and improve mining projects sustainability performance

Feb 27, 2013

The consideration of environmental constraints and issues is a fundamental component of all stages of planning, development, operation and decommissioning mining and quarrying projects. Provision needs to be made at all stages for the cost of environmental components since it is of fundamental importance that they be recognised as an integral component of any project. This paper presents an approach to environmental costing, suggested levels for budgeting, and the cost benefits.

Jan 1, 1990

The commercial development of the shallow (2200 ft2 400 ft) Windalia sand reservoir at Barrow Island provided the opportunity to conduct an intensive drilling programme using equipment and techniques designed for optimum performance.During the initial exploratory and reservoir delineation phase, 12 specific Windalia test wells were drilled using drilling equipment with an optimum depth range of 6QOO ft - 8000 ft and a 9 5/8 in by 7 in. casing programme was employed. The average time from commencement of move-in to rig release exclusive of coring for five representative wells was 187 hr during this phase.Development drilling commenced December 1966 with one rig, with the second in operation January 1967.As of January 1 1968, 168 development wells had been completed. The two rigs employed are drive-in units equipped with a telescoping .gelf raising doubles mast.Optimum depth range with 4 1/2 in. drill pipe is 2500-4000 ft. Casing programme is 8 5/8 in. by 5 1/2 in. Efficient performance was achieved immediately. The average time from commencement of move-in to rig release for 15 wells drilled early in the development programme was 99 hr.By application of experience and further modification of techniques, performance was improved to an average time of 72 hr per well for 15 wells recently completed.The major drilling problem on Barrow Island is surface hole drilling due to the very hard surface limestone combined with complete loss of circulation at sea level.In this operation, significant improvements have been effected. During the exploratory phase drilling, 12 1/4 in hole to set 9 5/8 in. casing, average penetration rate was 23 ft/hr. At the commencement of the development programme penetration rate, drilling 10 5/8 in. hole to set 8 5/8 in. casing, was 28 ft/hr for the 15 early wells considered, improving to 55 ft/hr for the 15 recent wells considered.This programme is a team effort and much credit must be given to the enthusiastic co-operation of the two drilling contractors.The current field record is 2 days 4 hr with a 4 1/2 hr move including the drilling of mousehole and rathole.

Jan 1, 1968

By H. M. Urban

This paper, one of a series being prepared for and published by the United States Bureau of Mines on methods and costs of mining at various mica mines in the United States, describes the methods now in use in the principal mica mines of the Southern Appalachian States. Those papers are designed to disseminate technical information regarding the methods used. The cost tabulations represent operating expenditures only and not total costs. It is recognized that publication of total costs might in some instances cause embarrassment to individual producers as well as to the industry as a whole. On the other hand, operating costs are essential to the technical discussion and study of methods employed. The attention of the reader is specifically called to this differentiation in order that no misunderstanding of the scope of the cost tabulations shall ensue.

Jan 1, 1932

By Yi Luo

In the study of the topographical effects on surface movement due to underground longwall mining, the factors that affect the incremental horizontal displacements are identified using 10 collected cases. Based on this study, the angle of surface natural slope is the major contributor to the incremental horizontal displacement while the total movement is also playing an important role in some cases.

Jan 1, 1996

By Dwight L. Sawyer

To provide technology that can help decrease the dependence of the U.S. aluminum industry on imported bauxite, the main ore of aluminum, the Bureau of Mines is investigating the extraction of aluminum from abundant domestic reserves of kaolinitic clay. Miniplant studies of the continuous leaching of calcined kaolin with boiling 25-pct HC1 acid resulted in a 93- to 99-pct extraction of the acid-soluble alumina in the calcined kaolin feed. Data are presented for an acid leaching study carried out in three or four continuously stirred tank reactors (CSTR) in series, feed rates of 100 to 250 lb/hr of calcined kaolin, and total nominal residence times of 0.7 to 2.3 hr. A material balance for a 176-lb/hr calcined kaolin feed rate in a circuit consisting of three reactors, four classifiers, and five thickeners is given. Data provide detailed compositional and physical information for calcined kaolin, process liquors, and acid-leached residue solids.

Jan 1, 1983

By Ann G. Kim

The U.S. Bureau of Mines mine fIre diagnostic methodology to locate and monitor fIres in abandoned mines and waste banks is based on the controlled sampling of the mine atmosphere to determine changes in the concentration of hydrocarbons desorbed from heated coal. To provide background data for this methodology, a laboratory study was conducted in which samples of coal and coal waste were heated under controlled conditions. Gas samples from the combustion furnace were analyzed for standard gases CO2 and CO and for the C1 to Cs hydrocarbons. In all tests, the concentration of desorbed hydrocarbons increased during heating and decreased during cooling. A dimensionless hydrocarbon ratio, Rl, was developed as the signature for heated coal. For bituminous coals, the value of Rl increases during heating of coal samples and decreases during cooling of the same samples. Generally, Rl values of 100 or more indicate coal sample temperatures of at least 100° C. The emission of higher molecular weight hydrocarbons from anthracite samples was very low, resulting in relatively low Rl values at all temperatures. Data from fIeld projects confIrmed these results.

Jan 1, 1991

By Andy Fortin, Jeet Basi, Simon Hille

Goldcorp’s Eleonore mine is situated in Ell Lake area in the northeastern part of the Opinaca reservoir in the James Bay region of Quebec. The design of the 7000 t/d process plant includes crushing, grinding, bulk sulphide flotation, separate concentrate and tails leaching and detoxification circuits and residue handling. Detoxified flotation tails are thickened and filtered. A portion of the filtered tails are blended with the thickened detoxified sulphide concentration for paste backfill. The remaining filtered tails are trucked to the waste management facility. This presentation will describe the challenges faced with the commissioning and subsequent ramp-up of the flotation tails filter plant and the successes achieved by the multi-discipline team at Eleonore.

Jan 1, 2016

Beneath some of New York?s most iconic buildings ? The Met Life Building, the Helmsley Building, the Waldorf Astoria ? crews are busily at work on the Metropolitan Transportation Authority?s long-awaited East Side Access (ESA) project. In fact, it is 14 floors beneath the famed Grand Central Station where one of the centerpieces of the project, the new Long Island Railroad (LIRR) station terminal, is being blasted and carved into shape. When completed in 2016, the $7.3-billion ESA project will increase LIRR?s capacity into Manhattan and significantly relieve congestion at Penn Station. Currently, 37 LIRR trains per rush hour roll into the crowded Penn Station where many riders must then transfer to subway trains to complete their commute. When completed, the ESA tunnels will bring an estimated 160,000 riders directly to Grand Central Station, saving those riders 30 to 40 minutes. Studies have found that more people work within walking distance of Grand Central than Penn Station. ?The benefits of the project are tremendous,? MTA Capital Construction President Michael Horodniceanu told more than 340 industry professionals attending the UCA of SME?s George A. Fox Conference in New York on Jan. 26. ?The ESA is the first expansion of the LIRR in 100 years. It will increase the East River tunnel capacity by 50 percent and will help support job growth around Grand Central.?

Jan 3, 2010

By A. L. D. Skury

In the synthesis of diamond, the precursor graphite must present a degree of crystallinity to assure optimum yield and quality for the transformed crystals. X-ray diffraction, SEM and TEM analyses were carried out to investigate the structural and morphologic transformations produced in natural graphite by high pressure-high temperature treatment. The present study had as its objective to characterize the morphological and structural changes suffered by a natural graphite that was subjected to high pressure and high temperature treatments in the region of diamond thermodynamic stability. The results indicate that the material that constitutes the gasket, for the deformable capsule, could act as catalyst in the graphite recrystallization process.

Jan 1, 2006

By K. Thirumalai

The feasibility of breaking hard rock by thermal weakening and subsequent mechanical impacting was tested, Field tests at a basalt quarry in Dresser, Wis., demonstrated that large hard-rock blocks (5 by 5 by 5 ft) could be effectively reduced in size by this method. A series of secondary breakage tests, using air-propane heating, resulted in an average heating cost of $0.36 per ton. This combination energy approach provides an alternate means of size reduction of large hard-rock boulders for quarry and for underground are chute and grizzly operations where mechanical methods, used alone, are ineffective.

Jan 1, 1975

By Francis J. Kelly

This Bureau of Mines study was made to obtain and present facts concerning the production and marketing of rare-earth metals and thorium in the Central and Southern Rocky Mountains (Arizona, Colorado, New Mexico, Utah, and Wyoming, referred to in this report as the region) and to review the current demand for these elements in the United States. Little or no published information was available on the marketing practices for these commodities. As a result of many inquiries from industry, potential prospectors, and the general public, the various factors of resources, production (present and potential), marketing, and consumption have been investigated, and the results are set forth in this report. Material concerning occurrences and deposits is from published references detailed in the bibliography.

Jan 1, 1962

By Woodcock J. T, Sparrow G. J, MacRae C. M

The external urfaces and interiors (as polished sections) of particles of coconut hell and extruded peat activated carbons taken from everal Australian carbon-in-pulp operations were examined with an optical micro cope, a scanning electron microscope, and an electron microprobe.Calcium carbonate (calcite) precipitated from the pulp was the major inorganic material on the external surfaces of the carbon particle, but several ore minerals, including quartz, hematite, pyrite, arsenopyrite, and clay minerals were also identified, along with trona, gypsum, a nickel cyanide, and a magnesium salt. Sections of carbon particles showed that calcite was virtually the only introduced inorganic material inside the carbons.It was distributed in the pores and cracks throughout the coconut shell carbon particles but tended to be concentrated in the outer layers of the extruded peat carbon particles. The mechanism of calcite formation and deposition is uncertain. Gold X-ray dot maps showed that gold was distributed through to the centre of coconut shell carbons and to a depth of at least 500 &#181;m in extruded peat carbons. The distribution of gold within the carbon particles was similar to that of calcite.

Jan 1, 1988