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By V. A. Vorob'ev, A. N. Larionov, E. N. Ivanov, M. A. Ryazanov

The aim of the research is to increase the recoverable value of poor, difficult-to-digest complex mineral raw materials. In the Republic Belarus, universal centrifugal-shock devices have been created for crushing, grinding and classification of ore and non-metallic mineral raw materials in dry mode, which differ from foreign analogues by a higher level of resource saving (including electricity and materials). Dry-ore preparation technologies have been tested on a pilot scale: fine crushing (replacing grinding in rod mills), grinding (replacing wet grinding in ball mills) and pneumoclassification on different types of ores, - which made it possible to identify the criteria for the suitability and unsuitability of mineral raw materials for their use. The possibility of regulating the upper and lower limit of the size of the finished material is established, the possibility of reducing the yield of slimes (-0,020 mm) to 5 times is determined. A comparative analysis of the contrast degree of separation characteristics of ore a similar granulometric composition, crushed in wet and dry conditions, is performed. The achieved contrast degree of gravity properties after dry grinding - 104,3; after the wet - 60.2. When enriching on a centrifugal concentrator, gold recovery to the concentrate after dry grinding increased by 13.12% while improving the quality of the concentrate from 78.3 g/t gold to 90.75 g/t. When testing the gravity-flotation scheme for the enrichment of poor gold-quartz ore, the increment of gold extraction after dry grinding was 7.6% for gravity and 9.5% for flotation; the total increase in extraction is 17.1%. The possibility of flotation of a larger material after dry grinding has been proved, with an extraction gain of 1.5% compared to the flotation of thinner material after ball milling. The influence of dry technology on the efficiency of the leaching of gold and silver (an extraction gain of 5.5 to 10%) and heap leaching (extraction gain - up to 18.3%) was studied. The positive influence of dry ore preparation technologies on the efficiency of gold and silver heap leaching and heap leaching, thickening and filtration is proved. Lines of dry ore preparation technologies can be used in modular complexes for processing technogenic raw materials.

Jan 1, 2018

By A. D. S. Gillies

The effectiveness of coal mine face ventilation and the ability of airflow to maintain satisfactory methane and respirable dust levels in the working face area has been studied through the use of scale modeling techniques and underground testing procedures. In particular, consideration has been given to examination of the effects of operation of a high airflow, machine mounted dust scrubber unit on face air patterns. Results obtained through a cooperative study with the Peabody Coal Co. demonstrate that new mining cycles can be considered that increase production efficiency while maintaining satisfactory ventilation conditions.

Jan 1, 1986

By Qinghai Pang

"With the increasing proportion of bituminous coal in blend coal, the safety of blend coal during pulverization and transportation is gradually being paid more and more attention. Therefore, the explosivity of bituminous pulverized coal (PC) with different volatile content from 25 to 38% was studied by measuring the combustion flame length after its injection into a glass pipe with the heat source installed in the center. The results indicated that high volatile content bituminous PC is apt to have higher explosivity. By blending different bituminous PC with 10% anthracite, the explosivity of bituminous PC showed a positive correlation with the proportion –OH radical. However, different bituminous PC seemed to have the same explosivity when the addition of anthracite increased to 20%. With the further increasing proportion of anthracite to 30%, the explosivity of bituminous PC with high –OH proportion became negligible while a weak explosivity of high –CH3 proportion bituminous PC still remained.IntroductionWith the increasing iron ore prices and decreasing steel prices, it has become critical for iron and steel enterprises to control the cost in ironmaking and steelmaking process. Blast furnaces (BF) are the main consumer in ironmaking process, which occupies 70% fuel consumption of total steelmaking process [1]. In this circumstance, any means necessary is taken by BF operators to lower the cost of iron in production. Coke and iron ore are the main expense in this process, who takes up a very high proportion in total cost. Pulverized coal injection (PCI) is the most efficient way to reduce coke ratio, which replace coke with relatively cheaper PC.At present, most of BF is injected with blend coal in the consideration of decent combustion property and quantity of heat. Simultaneously, bituminite and anthracite blending is an effective method to obtain blend coals with required composition and performance, such as volatile and ash content, etc. Nevertheless, a very huge gap was found between the price of bituminous coal and anthracite in some regions of China, in which the price of bituminite can be just 70% of the price of anthracite. Thus, iron enterprises in these regions attempt to possibly amplify the proportion of bituminite in blend coal. Increasing proportion of bituminite results in higher volatile content in blend coal, by which the safety of blend coal during pulverization or transportation was deteriorated.Relatively, coals with higher volatile content usually possess stronger explosivity, which means that volatile and explosivity may related to some extent. However, the relationship between volatile and explosivity is not of certainty for some PC with high volatile content around 40% was found to be inexplosive in comparison to the coals with lower volatile content. With the increasing proportion of bituminous coal in blend coal, investigations on the factors of PC explosivity have become more and more important. Therefore, bituminous coals with different volatile content were selected. The explosivity of blend coal and its relationship between volatile content and functionality was investigated in this research."

Jan 1, 2014

By Howard J. Haselhuhn

The effectiveness of selective flocculation and dispersion processes for the concentration of hematite ore are strongly dependent on the ionic content of the process water. It has been noticed that magnesium ions are more detrimental to iron recoveries during gravity separation and flotation processes than calcium. This phenomenon was studied by measuring the zeta potential of hematite ore at various concentrations of sodium, magnesium, calcium, strontium and barium at a pH of 11. Results show that zeta potential inverts from negative to positive at concentrations as low as 0.16 mM of magnesium ions in the solution. It takes a significantly higher concentration (1.25 mM) of calcium ions to achieve the same effect. This difference is attributed to the ability of magnesium ions to adsorb to all surface hydroxyl groups, whereas calcium, due to its larger size, can only adsorb to every third hydroxyl group. This hypothesis was confirmed by results similar to those seen with calcium when this test was repeated with strontium and barium ions. The tendency for calcium ions to adsorb to every third surface hydroxyl group causes higher concentrations of calcium to be less detrimental to hematite concentration processes than magnesium.

May 1, 2012

By Porter I

Rock mass classification systems have emerged as a powerful tool which can be used for assessing ground conditions and determining support requirements in underground mines. They should not be used as a substitute for complete engineering design, but rather as a supplement to observational methods and analytical study. In general, the use of rock mass classification is attractive, but each classification system has various deficiencies. Use of any particular system should be made only with knowledge of that systems limitations. It is desirable to employ a number of systems and design methods which will allow for comparison and lead to a better understanding of the rock mass condition.The Rock Mass Quality system (Q-System), developed by the Norwegian Geotechnical Institute, and the Rock Mass Rating (RMR) System, Bieniawski, were designed primarily for civil engineering structures. Laubscher et al (1978) further developed the RMR-system specifically for rock mechanics engineering in the mining industry. A method of stope design, which introduces a stability factor for the rock mass and compares this with hydraulic radius, was developed by Mathews et al (1981). This paper reviews the above systems by applying them to stability assessment of crown pillars in two Australian metal mines and provides a critical analysis of the various approaches. In particular each system will be analysed to determine its suitability for use in crown pillar design. The most suitable system(s) will form the basis for future development in crown pillar stability analysis.

Jan 1, 1994

Mineral resource and ore reserve classification defines the risk associated with quoted resource tonnes and grades, allowing the interested party to make a judgement as to the `worth' of the resource statement. The JORC Code and Guidelines (1992) are now well entrenched as the foundation upon which gold and base metal deposits in particular are publicly reported. There are three categories of resource, namely Measured, Indicated or Inferred reflecting decreasing levels of confidence. The ore reserve, that is the economically mineable part of the resource, is classified as Proven or Probable and can only be drawn from the Measured and Indicated resource categories. As summarised by Stephenson (1995), resource/reserve classification has been an issue ever since the earliest days of mining in Australasia where, like elsewhere in the world, the industry, for a long time, lacked firm reporting guidelines. Those currently adopted in Australasia as the minimum standards for companies reporting to the Australian Stock Exchange (ASX) have been developed and revised since 1972 by The Australasian Institute of Mining and Metallurgy (The AusIMM), the Australian Institute of Geoscientists (AIG) and Australian Mining Industry Council (AMIC). Debate is now underway in terms of adopting an international code. The Code specifically does not attempt to regulate either the classification technique nor the method of estimation of the resource/ore reserve, but rather places the responsibility for this task on a `Competent Person' whose experience will decide the appropriate approach for a given commodity/orebody. The Competent Person must be a Corporate member of either The AusIMM or AIG with five years experience `relevant to the style of mineralisation' under consideration.

Jan 1, 1996

By James C. Barker

The Bureau of Mines evaluated the tin development potential of the uplands between the Kanuti and Hodzana Rivers from 1978 through 1980. Chemical and petrologic data indicate that local granitic intrusions are generally similar to "tin granites" that contain tin deposits elsewhere. The tin mineral cassiterite (SnO2) was identified in chlorite-rich greisen from the Sithyiemenkat pluton. Greisen zones are located near the intersections of high-angle, linear structural features, and samples contain up to 0.23 pct Sn. One bedrock exposure of greisen is 10 to 15 ft wide. Although some lode mineralization is present, the deeply eroded nature of the region suggests larger tin-bearing cupolas may have existed prior to erosion. Extensive stream gravel deposits have not been affected by glaciation, and potential exists for placer tin deposits. Especially favorable is a large semiclosed basin drained by the Kanuti Kilolitna River. Heavy mineral concentrates collected from surface alluvium in the Kanuti Kilolitna River valley contained up to 51.2 pet Sn (0.02 to 0.4 lb/yd3 Sn), up to 5 pct W, up to 0.4 pct Cb(Nb), and up to 0.1 pct Ta. The concentration of heavy minerals is expected to in- crease with depth. Detailed mapping and extensive surface and subsurface sampling will be needed to quantify the mineral development potential of the lode and placer tin deposits in the uplands.

Jan 1, 1986

Constraints on the mineral industry are best treated as issues that have to be understood and managed in partnership rather than in conflict with communities. The Zapopan development at Mt Todd in Australia and the Martha Hill development at Waihi in New Zealand are but two of many recent successful examples at the local level. However, at the national level, the issues are more complex and more difficult to resolve because the most influential stakeholders are now the urban electorates and governments defer to their perceptions when making decisions and policy.

Jan 1, 1995

By Doyle J

The direct method of gas content determin ation developed by McCulloch and Diamond of the U.S.B.M. has been adapted to estimate the gas content of coal seams from slim exploration borecores in the Southern Coalfield. Emphasis has been placed on the measurement of this parameter without the physical destruction of the core which is required for subsequent chemical analysis. In field and laboratory equipment is simple and inexpensive. It enables the determination of lost and desorbed gas from a fresh geological core. Residual gas is not measured but is considered to be relatively low and of no consequence in ventilation considerations. Results to date show good correlation with those obtained from underground face samples. Gas contents from the mined seams varying from 2 m3/tonne to 14 m3/tonne have been measur- ed with this apparatus. Gas desorption characteristics of South Coast coals have been found to closely follow exponential mathematical Models.

Jan 1, 1983

By Lockhart D. A, Gleeson P, Lang S. C

The Glenrock Group forms the uppermost part of the Early Devonian to Early Carboniferous Burdekin Basin sequence in the Townsville hinterland, north Queensland. As redefined, three formations make up the Glenrock Group. The Percy Creek Volcanics (base), the dominantly epiclastic Mount Douglas Formation, and the Horse Pocket Volcanics (top). The Ellenvale beds unconformably overlie the Mount Douglas Formation and Percy Creek Volcanics and have been excluded from the Glenrock Group as defined by Wyatt and Jell (1980). Three facies associations are recognised in the Mount Douglas Formation: Alluvial Plain facies, Alluvial Fan facies and Lacustrine facies.Deposition of the Glenrock Group, began with the eruption of massive basalt and basaltic andesite lavas, probably in a volcanic arc setting. With time, the volcanism evolved to become more dacitic to rhyolitic in composition. Waning of the volcanic activity appeared to coincide with uplift of source areas (probably to the west). Deposition on an alluvial plain during this waning volcanic cycle, gave way to alluvial fans at the margins of the uplifted terrain. As the uplift ceased and the system became more mature, the alluvial fans gave way to widespread lakes. Rhyolitic ignimbrite and airfall tuff, interbedded with the alluvial plain, alluvial fan and lacustrine facies, indicate that some volcanism continued, probably vented in the uplifted terrain to the west.

Jan 1, 1990

Two ends of a longwall face are not only concentrated locations of equipment, but also provide ventilation and access. The roof strata stability here has an important influence on mining coal and safety. Based on field obser- vations in the gateways at Zaozhuang Colliery (Shandong Province) and model tests, the author developed a structural model of the overlying strata at the ends of the longwall face - the arc triangular cantilever plate - to which the elastic theory of plates can be applied. Factors influencing the stability of the cantilever plate and its breaking character- istics are discussed. Requirements and design parameters for supports at face ends are pro- posed, based on these factors.

Jan 1, 1986

By Draper J. J, Jell J. S

The Burdekin Basin in the Townsville hinterland is an intracratonic extensional basin which contains up to 4500 m of marine and continental siliciclastics and carbonates. The basin sequence is recognised as having accumulated during five major episodes of deposition. Facies analyses of these show that each consists of one or more transgressive or regressive phases. Each episode led to the accumulation of thick sequences in several half-grabens in a transtensional back-arc setting. The depositional episodes can be recognised in comparable sequences in the Broken River Province to the west and Drummond Basin to the south.An Early Devonian episode resulted in the deposi-tion of dominantly marine facies, currently mapped as Fanning River Group, in the northern part of the Burdekin Basin. Two transgressive phases are recorded there, firstly in the Pragian, then later in the late Emsian to early Eifelian. A Middle Devonian episode is represented by dominantly marine facies of the Fanning River Group, representing the peak of a widespread late Eifelian to Givetian transgressive phase. A Late Devonian episode is characterised by continental facies of the Dotswood Group. Deposition occurred during a major regressive phase in response to regional uplift of surrounding areas, and the onset of acid-intermediate volcanism to the south. A Late Devonian to Early Carboniferous episode followed, which was a period of alternating marine transgressions and non-marine regressions that resulted in the deposition of the Keelbottom Group. A final Early Carboniferous episode, marked by the deposition of calc-alkaline volcanics and non-marine faciesòof the Glenrock Group, was a direct outcome of Early Carboniferous subduction further to the east. Compression of the basin followed in the Late Carboniferous, resulting in folding and reactivation of basement faults.

Jan 1, 1990

By Gary E. McIntosh

This paper will discuss a US Bureau of Mines project designed to assess and predict the impacts which surface coal mining will have on the regional shallow groundwater systems in the Powder River Basin. The primary objective will be met through the accomplishment of the following: (1) The design and establishment of a regional network for monitoring shallow groundwater systems in the basin; (2) monitoring the direction and rate of flow, water quality, and aquifer characteristics of the shallow groundwater systems; and (3) development of a regional groundwater simulation model, with appurtenant subroutines to determine local effects.

Jan 1, 1980

By Marco Vinicio Guamán Alarcón

O modelo do Gradiente de Tensão (SG) e a Teoria da Distância Crítica (TCD) são usados para estimar o limite de fadiga de corpos de prova com entalhes alongados, e essas estimativas são testadas em C(T) modificados submetidos a tensões cíclicas de amplitude constante com uma razão de tensão R = 0.1. Os valores medidos são comparados com as previsões feitas por ambos os modelos. As previsões do modelo SG estiveram mais de acordo com os resultados experimentais. Também foi demonstrado que o modelo SG é quase equivalente à TCD no caso de entalhes com raios grandes, quando a TCD usa o método do ponto. Para o caso de entalhes afiados, os valores dos limites de fadiga previstos pela TCD são mais conservativos que os previstos pelo modelo SG.

Aug 17, 2017

By Hellsten KJ, Butt CRM

Major Francis Hamilton Buchanan coined the term `laterite' (Latin; brick-rock) in 1807 for the red earths used for building blocks in southern India. Although these earths were actually weathered basalts, the term is now applied to weathering profiles developed upon a wide range of bedrocks. The Ni-laterites are a special class within the broad laterite family.

Jan 1, 1996

By Jun Li, Lingling Zhang, Daqiang Cang, Guizhou Zhao

Pilot trial of direct modification of molten blast furnace slag and production of high acidity coefficient slag wool fibers were investigated nearby a blast furnace. Molten blast furnace slag discharged from blast furnace and then directly flow into specialized modification furnace and quartz was simultaneously added into the molten slag as modification agent. The modified molten slag was electric heated to 1500–1550 °C and then the melt was produced into slag wool fibers through high-speed centrifugation method. Melt with acidity coefficient of 1.2, 1.4, 1.6 and 1.8 were investigated and fibers with corresponding acidity coefficient were produced. Slag wool fibers with shot content of 5.5, 5.8, 6.2, 6.8% and average diameter of 4.5, 4.9, 5.6, 6.4 lm for four samples were successfully produced, respectively. Total energy consumption and production costs decreased by 50–70% compared to traditional cupola furnace method. This method provides an energy-saving and emission-reduction technology for the direct utilization of molten blast furnace slag.

Mar 1, 2018

By Edward M. Weiss

THE emphasis in some political quarters on hemispheric unity and defense indicates Latin American mineral resources should be more extensively developed. However, United States mining companies have, in many instances, been discouraged by the laws of southern neighbors. At the same time, some of the countries have liberalized their mining laws in an effort to attract investments from the United States. The resultant confusion has been detrimental to all concerned. Ownership of Mineral Deposits Examination of the mining codes of Latin American countries shows that, without exception, governments reserve the right of direct ownership of all mineral resources. Ownership can be divided between the Feredal Government and the states or among the Federal Government, the states, and private individuals. However, in the majority of the nations constitutional authority vests all mineral rights solely in the Federal Government. Mexico is the only country that has expressed Federal ownership as imprescriptible; the other republics have not defined the exact significance of government ownership. The implication derived from the general economic and political climate is that all mineral resources are ultimately to be regarded as a national heritage. Whether a concession granted to an individual or corporation carries any right of private property is shaded with a variety of meanings. The exceptions at one extreme are Argentina and Bolivia, whose laws state explicitly that a concession granted to a juridical person is an act of the state, and the land becomes the private property of the individual, and the concessions constitute real property. However, in Mexico mining concessions or grants do not create rights of fee-simple ownership. The concession only conveys the exclusive right to explore, develop, and work the deposits. The mining property remains the property of the state. In some instances exploitation concessions represent a compromise between private and government ownership. In Honduras the period granted to a mining enterprise is fixed at 90 years. At the end of that time, the enterprise and all installations revert to the state without compensation.

Jan 1, 1952

By H. N. Thomson

(Butte Meeting, August, 1913.) GENERAL. THE Tooele plant. off the International Smelting & Refining Co. is situated at the mouth of Pine canyon, Tooele county, Utah. It is connected with the main line of the San Pedro, Los Angeles & Salt Lake railroad by the Tooele Valley. railway, and is about 7 miles from Tooele Junction. Fig,. 1 is a general view of the plant. The copper plant has been in operation since July, 1910, and the first blast furnace it the lead plant was blown in on Feb. 29, 1912. The location of the plant was selected on sloping ground with the idea of using gravity to the fullest extent and thus keeping labor at a minimum. Practically the entire plant is constructed of steel, reinforced concrete, and. brick.

Jan 7, 1913

By Ron Bernard

HW Process Technologies has successfully developed and commercialized various applications utilizing Engineered Membrane Separation (EMS?) systems for the processing of acidic copper hydrometallurgical solutions and wastewaters. Copper hydrometallurgical EMS? applications include water balance control and increased copper concentration in heap and dump copper leach operations, tankhouse bleed stream treatment to separate/recover copper and cobalt from iron, and removal of PLS/Electrolyte suspended solids/colloids to eliminate "crud" formation during copper SX/EW. Similar applications are underdevelopment to provide ionic separations in copper refinery bleed streams, copper smelter acid plant streams, as well as organic/LIX removal from aqueous electrolyte and raffinate streams. Copper mine wastewater EMS? applications include treatment of copper leach solution contaminated groundwaters for copper recovery and treatment of unwanted heap/dump drainage to provide enhanced precipitation, a smaller precipitation plant, improved operating costs and better quality discharge water, particularly in terms of TDS and sulfates. A discussion of the EMS? technology and general separation results on typical process solutions and wastewaters will be presented. HW Process Technologies, Inc. commercial installations treating copper pregnant solutions and leach solution contaminated groundwaters are in-place at an old Asarco smelter/refining operation, Mexicana de Cananea copper mine, and a major U.S. copper mine, with several additional installations pending. Several case studies, including results from a selection of these installations, will be included with detailed capital, operating cost, and system payback data.

Jan 1, 1999

By Koppe J. C, Costa J. F C L

This paper compares different results for overburden volume estimation assisted by geoestatistics, particularly using kriging methods. The main goal is to obtain the most reliable digital terrain model for the calculation of the overburden volume. The data was collected on an irregularly spaced grid and interpolated values were calculated to provide a denser, more regular data set before volume estimation. The field work was developed at the Butia-Leste Coal Mine, southern most Brazil, where an accurate survey was done using a total station theodolite with electronic data collector. The study was developed in five main steps: data acquisition, exploratory data analysis, spatial continuity measurements, point and block kriging estimation and verification of the results. Data acquisition was carried out on a 5 x 5 in grid. This dense grid provides an exhaustive data set of the real terrain against which data subsets can be compared for the various interpolation procedures and volume calculation. This provides an interesting insight into the influence of the number of data on the estimation error. Univariate statistics were used to compare each data subset and the exhaustive dataset. Ordinary kriging on the data subsets followed by contouring was carried out using Geoeas and Surfer software respectively. A subroutine written in C provided the link between the files generated in Geoeas and subsequent contouring routines embedded into the Surfer package. Omnidirectional and directional variograms were modelled defining the parameters for kriging estimation using Geoeas. Different variogram models were checked through cross validation prior to kriging. A comparison between the magnitude of the differences in volumes calculated with the different DTMs was attained. These final result indicates the sensitivity of the volume obtained to the number of data points. As the number of data points increases the estimation error decreases, but at some point there is no significant decrease in the final volume with the collection of additional data.

Jan 1, 1995