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The relationship between the maceral composition of coal and the strength of the coke produced from that coal has received a great deal of attention in recent years.Studies using two Bulli Seam coals, and blends of Bulli and Wongawilli Seam coals, from the IIIawarra Measures of the Southern Coalfield of New South Wales were carried out.The optimum range of vitrinite was found to lie between 45 per cent and 60 per cent (mineral matter free).Above and below this vitrinite range coke strength deteriorated. Coke strength indices increased with rank, and the optimum vitrinite content increased with an increase in rank. These changes require confirmation as trends by testing a third level of rank. It was noted that vitrinite content decreased with an increase in the specific gravity of separation of the coal.Use of petrographic analyses will increase confidence in choosing coals for coking, provided the coals are well known. Such analyses offer the possibility of greater flexibility in coal purchases and the possibility of producing a marketable blend from coals, which have limited market potential. Critical base coals for blends can be conserved.Significantly more work is required before coal reserves can be utilized to optimum advantage. This work would require extension of the studies discussed in this paper and, in particular, the testing of a wider range of rank.

Jan 1, 1971

By D. Imeson, T. Grammatikopoulos, M. Aghamirian, M. Oliazadeh

"More than 70% of potash is produced worldwide by froth flotation. Flotation of potash was developed in the early 1930s. Amines are widely used for flotation of sylvite (KCl) from halite (NaCl) and insoluble materials such as clays. Amine collector is also absorbed by clays. Therefore, clays are usually separated by scrubbing and de-sliming prior to flotation. Alternatively, slimes can be floated ahead of potash flotation. Flotation recoveries of sylvite are commonly in the range of 85%, while losses can occur in slimes, flotation tailings and make-up of process brine. Ores containing free coarse-grained sylvite are generally screened, whereas both fine and coarse fractions are conditioned and floated separately. The unique features of potash flotation include solubility of sylvite in water, the size of particles floated and fast kinetics. Particles up to 2.3 mm can be floated and about 50% of flotation feed can be removed in the rougher stage in few minutes. The main challenges in potash flotation are the recovery of potash from slimes, flotation efficiency in the presence of carnallite and recovery of coarse potash grains. A review of potash flotation shows that there is still room for improvement in both coarse and fine potash flotation. The present paper reviews the most significant flotation parameters including reagent type and dosage, flotation circuits, flotation equipment size and new developments in potash flotation. The latter include new reagents, flotation technologies (Hydrofloat, Jameson and column cells) larger flotation cells and slimes flotation.INTRODUCTION Potash is the common industrial term for potassium in various chemical combinations and minerals soluble in water. About 90% of potash produced worldwide is used as agricultural fertilizers. Flotation is the main treatment process of sylvinite (KCl-NaCl) ores for recovery of sylvite (KCl). Potash concentrate should contain a minimum of 95% KCl and be relatively free from 0.2 mm KCl fines. The flotation process for beneficiation of potash ores was developed in United States and Russia concurrently in the early 1930s. In 1934, Potash Corporation of America applied flotation process in a commercial scale (Tippin R.B. and Huiatt J.L). In the initial application, halite (NaCl) was selectively floated by employing lead chloride as an activator and soap as collector. The sylvite concentrate was reported in the cell underflow."

Jan 1, 2012

By Albert L. Toenges

[The i~ ortance o~ S3~e, fdequnt, nQ economical tr~n~po~t~t on 8ys~em Th~a bee~ e~~~~siz8d by the introduction of mechanical loading in co 1 mines, pa.rticula:c y \'r~ e::-e ~o?oile loaciine; ~ac~ine!;j rrre u .... ed. This papar i tr_e . eco:1d or' ?. ~eries deGcribi 1{) t:;'~~11>ort:ltion G stems et1-p oyed in mech3JlizeG. f!lincs. Progre,-s ?. epo~ t J...2.t deal t ~~tirel.: ,'Ii th the l:se of rail .laulagr £or c;atl:erine tran~ortc;tion, ailc, in t-!is paper 'Ii 11 be i acuss d c .icilY rub"col'-t? ro ~ t:tto::"ing as Ie _ as ani:naJ., con-",reyor, an ot.he~ systems of rnil gatheri?1.g. ~ho l)urpo~e of this invosti-gation is, as outlined in Progress ,~ort 1, to studT . Q analyz0 v rious systems nov.: in. u"'e El.I1d to derivQ cor..cl :cicn .... tllcrcfrom.]

Jan 1, 1941

By A. M. Elmahdy

An amphoteric collector was tested for dolomite removal from phosphate ore. The effects of some operating parameters and their significance on the flotation of dolomite were studied using statistically designed experiments. The parameters studied were impeller speed, pH and collector dosage. Analysis of the results showed that pH is the most significant parameter. Moreover, a concentrate containing 0.53% MgO and ~31.1% P2O5 with a recovery of ~ 90% can be achieved at optimum values of studied parameters, i.e., a pH of 12, an impeller speed of 1,000 rpm and a collector dosage of 2.5 kg/t.

Jan 1, 2007

By Bjarne Ekberg

"The most economical way of dewatering mineral concentrates is to reduce the moisture content in the material mechanically using thickeners and filtration avoiding thermal drying whenever possible. In addition to this, the dewatering process should produce low moisture cake, high quality liquid, consume little energy. As a part of the dewatering process The CERAMEC® capillary filter has been proven to meet these requirements in over 150 installations. The filtration is done by using ceramic filter plates with small pore size. The capillary action in the filter medium secures gas free filtration at good vacuum, and due to the small pore size, filtrate is crystal clean and particle free. The energy consumption is minimal. This paper will discuss results from filters installed at Pyhäsalmi Mine Oy in Finland where the technology was has been used since the late eighties. Results from more recent installations like Los Pelambres in Chile and LKAB in Sweden will also be discussed.INTRODUCTIONThe idea of using capillary action to make dewatering more efficient was invented two decades ago. Ten years later whole filter plants utilizing the new method were delivered to mine concentrators for dewatering of mineral concentrates. Further development of ceramic membrane plates made it possible to meet the requirements in iron ore dewatering. In addition to low cake moisture, high capacity and low energy consumption, there are a lot of environmental advantages in using capillary filtration. One of them is clear filtrate.CAPILLARY FILTRATIONA micro-porous filter material behaves like a large number of narrow capillaries forming a network. When a pressure difference ?P is applied over the wetted, hydrophilic pore with the radius r, the force striving to push the water out of the pore will be ?Ppr2. The force striving to hold the water in the pore will be the vector force 2pr? cosa of the surface tension ? and the cosine contact angle a. Equalling those forces and solving the equation for ?P we get"

Jan 1, 2003

By D. M. Walters

To achieve safe and healthy working conditions in shaft sinking operations, ventilation, and where necessary cooling, must be provided. These requirements are considered for sinking vertical, sub-vertical and decline shafts. Regulatory requirements, determining air volumes and amount of cooling required, the various ventilation methods used such as force, exhaust, twin columns, air reversal using four gate systems and the equipment required to achieve this, are discussed. Consideration is also given to the sinking of single and twin declines using diesel equipment, calculating the air volumes required to dilute pollutants and the various methods for achieving this. Also discussed is the importance of having early ventilation design input to the overall design of the mine. In many cases ventilation can be the prime determinant for the size and configuration of the shafts or declines that have to be sunk.

Jan 1, 2009

By H. W. C. Prommel

While Utah remains an unimportant factor in oil production, exploratory drilling was carried on in six widely separated areas, extending from the southwest to the northeast corner of the state. One new gas field, the Last Chance or Starvation Creek anticline in Emery County, and two new gas horizons in the Clay Basin field of Daggett County, were thereby discovered during 1934. Exploratory Drilling South Central Utah Emery County—Last Chance Anticline.—The test of the Ramsey Petroleum Corporation in sec. 18, T.26S., R.7E., on the apex of this anticline (vert. closure 700 ft.; area within closing contour line, as mapped by U.S. Geological Survey, 26,000 acres) encountered gas in the Moenkopi formation of lower Triassic age at depths ranging from 2530 to 2863 ft. The total thickness of sandstone, sandy shale and -limestone beds in which gas was encountered is approximately 50 ft. The well was tested at a depth of 2755 ft., gaging 21,000,000 cu. ft. of gas, R.P. 410 lb. The well is being plugged back to the lowest gas horizon at 2771 ft. from a total depth of 3168 ft. Gas from this well probably will be used for the drilling of a second well structurally lower, to test the oil possibilities of the Moenkopi formation as well as of the upper and lower Pennsylvania formations, of which the latter so far remains untested in South Central Utah. The well was not drilled deep enough to determine more definitely the western margin of the petroliferous Paradox Basin of lower Pennsyl-vanian age of southeastern Utah. Woodside Anticline.—This field, lying immediately northeast of the San Rafael swell, contains, according to maps of the U.S. Geological Survey, 8380 acres within its lowest closing contour line 700 ft. below the apex. A well was drilled by Utah Oil Refining Co. at the apex in sec. 12, T.l9S., R.l3E., during 1924. Gas was encountered in the Moenkopi and Kaibab formations of Triassic and Carboniferous (Permian) age respectively. The flow is estimated at 21,000,000 cu. ft., R.P. 900 lb.,

Jan 1, 1935

By Kevin O?Callaghan

Applying Legal Concepts - The Crown must consult, and where necessary accommodate, when: - Crown has knowledge, real or constructive, of the potential existence of Aboriginal rights or title and contemplates conduct that might adversely affect it - Duty to consult is triggered at a low threshold - How much consultation necessary? - Proportional to the strength of claim and potential impact - Spectrum: notice to direct involvement in decision making - Not duty to agree or to get consent (no veto) - Reciprocal: Duty requires good faith and sincere engagement on both sides Role of Proponents: Crown may delegate procedural aspects of its legal duty

May 1, 2010

By Zbigniew Zurecki

The selection of atmosphere composition is critical for controlling surface quality of reactive aluminum alloys during solution treatments. An improper selection of annealing atmosphere can result in surface blistering in AI-Mg and sub-surface depletion of lithium in AI-U ingots. To determine optimum atmosphere compositions for homogenizing A1-Mg and Al-Li alloys, Ii number of exploratory experiments were carried out in air, nitrogen, and carbon dioxide based atmospheres including reactive impurities or additive such as moisture and sulfur hexafluoride. This paper describes the influence of these atmospheres on high-temperature oxidation and sub-surface defects. The results are discussed in terms of the change in Pilling-Bedworth ratio.

Jan 1, 1996

Bortech’s BoreClad corrosion protection system will be displayed at MINExpo. BoreClad is an innovative system for inside diameter cladding of nozzles, tubes and other circumferential devices. Pressure vessels, mud pumps and other mining equipment must be protected from corrosive caustic chemicals. Usually manufactured from mild steel, they can be clad with a protective material, such as stainless steel, to provide corrosion resistance. However, most welding processes leave voids where corrosion can damage the base metal. BoreClad provides void-free welds by combining gas metal arc welding with automated feed and rotation of chuckable parts. Workpieces of up to 915-mm- (36-in.-) long with a 460-mm- (18-in.-)swing can be clad with stainless steel, Iconel or other exotic metals. In addition to eliminating the voids associated with hand welds, BoreCladcan lay more than 2.2 kg/h (5 lbs/hour) of metal. That is a significant reduction in weld time. Web sitewww.bortech.com.

Jan 1, 2004

By R. L. Grayson, F. Giana, R. Aspinwall

Small-mine and contractor Fatal Incidence Rates have been a problem for over 20 years in the coal industry, and the rates persist as unacceptably high. This paper briefly retraces historical information and data on the continuing problem and recounts the many unsuccessful efforts and initiatives to address the problems effectively. Next the results of a review of international literature on addressing the problems are presented. After focusing on a method to pinpoint the trouble spots more specifically through a nested data analysis, suggestions are provided on how the problem may potentially be addressed more systematically and effectively in the U.S.

Jan 1, 2006

By R. Altindag

Engineers and researchers need to estimate the mechanical properties of rocks from P-wave velocity. In previous studies, the researchers have investigated either the limited values or all the data belonging to sedimentary, igneous, and metamorphic rocks together in the same statistical analysis. In this study, the raw data pertaining to only sedimentary rocks was taken from previous studies and evaluated. For this purpose, a total of 97 samples of sedimentary rock types were subjected to statistical analysis. First, the relationships between P-wave velocity and physical-mechanical properties were investigated by simple regression analysis. All the data were then subjected to multi-regression analysis. Some empirical equations with high correlation coefficients were derived for rock engineers. The equations obtained from the analyses are compared with previous equations found in literature.

Jan 1, 2012

By Jacob Carr, Christopher C. Jobes, Chenming Zhou, LaTasha R. Swanson, Jennica Bellanca, Jingcheng Li

Magnetic proximity detection systems (PDSs) are used with continuous mining machines (CMMs) to protect miners from striking and pinning accidents. Generators are used in a PDS to create magnetic fields covering the space around a CMM. The PDS determines the proximity of a miner relative to the CMM based on the magnetic flux density detected by a miner-wearable component (MWC) and simultaneously alerts the miner and stops the motion of the CMM if the miner is within a proximity that creates a striking hazard. A stable magnetic field is essential to the accuracy of the proximity calculations performed by the PDS. This paper presents the results of a systematic study of the magnetic influence of two types of steel structures found near a CMM— the body of the CMM itself and the wire mesh used for roof and rib control. The results show that the steel of the CMM body can change the magnetic field distribution and also alter electrical parameters of a PDS by changing its generator current. The study also shows that, depending on the distance between the wire mesh and a generator, the magnetic field can also be altered.

By Jacob Carr, Christopher C. Jobes, Chenming Zhou, LaTasha R. Swanson, Jennica Bellanca, Jingcheng Li

Magnetic proximity detection systems (PDSs) are used with continuous mining machines (CMMs) to protect miners from striking and pinning accidents. Generators are used in a PDS to create magnetic fields covering the space around a CMM. The PDS determines the proximity of a miner relative to the CMM based on the magnetic flux density detected by a miner-wearable component (MWC) and simultaneously alerts the miner and stops the motion of the CMM if the miner is within a proximity that creates a striking hazard. A stable magnetic field is essential to the accuracy of the proximity calculations performed by the PDS. This paper presents the results of a systematic study of the magnetic influence of two types of steel structures found near a CMM— the body of the CMM itself and the wire mesh used for roof and rib control. The results show that the steel of the CMM body can change the magnetic field distribution and also alter electrical parameters of a PDS by changing its generator current. The study also shows that, depending on the distance between the wire mesh and a generator, the magnetic field can also be altered.

By T. B. Colman

Paper presented at the MEP '89 conference held in Madrid, 13-15 November 1989. Britain has sustained an important metalliferous mining industry over many centuries. Recently, new geological concepts and exploration techniques have indicated that there is considerable potential for the discovery of a variety of deposit styles, often in previously neglected areas. The recent discoveries at Aberfeldy (Ba-Zn-Pb), Gairloch (Cu-Zn) and Cononish (Au-Ag)in Scotland and Curraghinalt (Au-Ag) and Lack (Au-Ag-Pb) in Northern Ireland are illustrations of this potential. Some of the prospective areas for future exploration are described and an indication is given of the legislative framework within which mineral exploration and development are carried out

Jan 1, 1991

By Peter Makuvise, Alain M. Bantshi

"The Mazowe Gold Mine is managed by Metallon Gold (Zimbabwe) and is situated in the west-central part of the Harare greenstone belt. Orebodies here generally comprise shear zones which are in-filled with gold-bearing sulphides and quartz. The mineralised zones are up to 1 m in width, have average grades of 4 to 5 g/t, and mostly dip between 10º and 60º to the north.Mazowe Mine is one of the oldest mines in Zimbabwe, and exploration and development in this region dates back to 1890, with over 1.4 million ounces of gold produced to date. Mazowe mine comprises two underground operations, Mazowe and the BSV sections. Ore is processed in a single plant which consists of conventional crushing and milling and carbon-in-leach facility.Baldmin Projects was awarded the contract for the design, construction and commissioning of the 60,000 tonnes per month plant at Mazowe mine in 2014 for the processing of sand and slimes tailings from previous operations at Mazowe mine. The average grade of the tailings is 1.1 g/t. The plant consists of feed preparation, grinding, flotation, thickening of flotation concentrate, and carbon in leach (CIL). A pump station for hydraulic mining of the slimes tailings dam also part of the plant.Key features of the Mazowe sands Plant are described and include:• Hydraulic mining of gold tailings dump.• Feed preparation section that includes a (W x L) 2.4 m wide x 4.8 m trash screen, 250 m3 surge tank, a cluster cyclones with 2 x 500 mm diam. Cyclone.• Comminution circuit designed for a bond work index range of 10-12 kwh/tonne. comminution circuit is constituted with 3 ball mills, 1.83 m diam. X 6.71 m Long, 280 kW.• Flotation circuit comprising rougher bank, scavenger bank and cleaner bank. Rougher Scavenger bank is constituted of 6 x 6m3 flotation cells and 3 x 30 m3 flotation cells and the cleaner is constituted of 3 x 6 m3 flotation cells.• Concentrate Thickening with 6 m diam. Thickener.• Concentrate CIL (carbon in leaching): CIL circuit is comprised of 7 tanks with 2 leach tanks and 5 Carbon in leach."

Jan 1, 2017

By Jana Dobrovska

The paper deals with new approach for measurement and evaluation of chemical microheterogeneity of elements in polycomponent metallic systems (i. e. steels, Ni-alloys). The method is based on the original mathematical model for determination of distribution curves of dendritic segregation of selected elements and on the original mathematical model for determination of the effective partition coefficients of these elements in the structure of analyzed alloy. Application of the method at research of chemical heterogeneity of continuously cast steel slab is also presented. The original results of measurement of dendritic microheterogeneity of eight elements (Al, Si, P, S, Ti, Cr, Mn and Fe) in structure of nine zones of a transversal section of slab are given.

Jan 1, 2006

By D. A. Elgillani, M. C. Fuerstenau, J. D. Miller

Adsorption of lead and ferric iron on quartz and alumina is presented as a function of pH. Only the hydrolyzed species of these metal ions, FeOH++ and PbOH+, adsorb significantly on each of these minerals. Zeta potentials of quartz were measured as a function of pH in the presence of various additions of aluminum, lead, and magnesium salts. Sign reversal occurs at the pH values where significant concentrations of hydroxy complexes are formed. Models of adsorption are presented in the absence and presence of collector. The mechanism of adsorption of metal and collector species in the activation of nonmetallic minerals is still the center of considerable discussion in spite of the extensive study given this system. Until recently, the view was widely held that hydrated metal ions were responsible for this phenomenon. This fact is surprising, since it had been shown that the pH range in which flotation is effected corresponds to that in which metal ion hydrolysis occurs.' Additional support of this concept was pro vided by the work of Wolstenholme and Schulman in another system.' Later work has shown that hydroxy complexes of metal ions are the active species. These studies have also indicated that basic aqueous complexes of metal-collector may be necessary for flotation.3-7 Depending on the molecular weight of the collector, formation of these complexes may occur before or after precipitation of the metal-collector salt has occurred. Ion pair formation can occur when low molecular weight collectors are involved because relatively high concentrations of metal hydroxy complex and collector can be present in solution before precipitation occurs. This is not the case when high molecular weight collectors are used. A model of aqueous complex adsorption has been presented6,7 in which it has been assumed that adsorption occurs by the formation of water from adsorbed hydroxyl and hydrogen of the hydroxyl contained in the complex. Other authors8 have suggested that hy-droxy complexes are involved in these systems but that collector adsorption occurs by replacement of the hydroxyl of the adsorbed metal hydroxy complex with a fatty acid anion. All of these investigations have involved mineral surfaces that were negatively charged so that it is not possible to state with certainty whether hydrated metal ions or hydroxy complexes are the active species in this system. Use of a positively charged mineral should be helpful, however, since the hydrated metal ion will be repelled from this surface. On the other hand, if the hydroxy complex adsorbs by splitting out water, surface charge should have no effect because of the free energy decrease that the system will experience when water is formed. In this regard, sapphire is well-suited for study, since its surface is positively charged until approximately pH 9. Electrokinetic studies of quartz in the presence of various metal ions should also be useful in establishing the mechanisms of adsorption in these systems. That is, if the hydroxy complexes adsorb by water formation, drastic changes in the zeta potential should occur in the pH range in which hydrolysis occurs. In this view, adsorption of ions of widely different hydrolysis characteristics on both sapphire and quartz was measured. In addition, zeta potentials of quartz were measured as a function of pH in the presence of various metal ions and compared with flotation responses obtained under similar conditions. Experimental Materials and Techniques Reagent-grade aluminum, ferric and magnesium chlorides, and lead nitrate were used in this investigation. Adjustments in pH were made with reagent-grade HCl or KOH. Conductivity water, made by passing distilled water through an ion exchange column, was used in all of the experiments.

Jan 1, 1971

By V. D. Jalevsky

A new methodology of an experimental-analytical approach has been developed. It is used in building an information geomechanic monitoring system for the modeling of geomechanic processes during coal seam working. The approach synthesizes experimental (in-situ) measurements of rock pressure manifestation in separate points, methods of numerical modeling of processes on rock boundaries with coal, and a seam analytical calculation of rock mass in a spatial strained state. One of the realizations of this approach is the developed theory and calculation method of adjoining rock surface shift (overhang) formation during underground working of sheet deposits and of rock mass geomechanic state determination. There are description algorithms of cavity configurations with broken lengths of faces during underground working of useful mineral sheet deposits. These algorithms have been used in computer modeling of formations of adjoining rock surface overhangs and abutment pressure upon rock mass in the area of coal faces with irrectilinear longwalls. Peculiarities of surfaces shifts and stress allocation are established for different face schemes. The use of theory and methods alloww working out techniques of automatic control to receive processing algorithms of RPM measurement results and calculate geomechanic situations within panels in the process of planning and development as well as during mining, i.e., to carry out long-term prediction, in-line control, and short-term prediction of rock pressure manifestations.

Jan 1, 1996

By Mustapha A. Raji, Alafara A. Baba, Christianah O. Adeyemi, Aishat Y. Abdulkareem, Rafiu B. Bale, Malay K. Ghosh

The increasing demand for pure aluminum and aluminum compounds of industrial quality from kaolinite ore cannot be overemphasized. Nigeria is one of the African countries endowed with abundant solid mineral resources that have not been sufficiently exploited to assist its indigenous industries. A wide array of applications of pure aluminum and its compounds are available, such as paper filling, refractories, adsorbent, catalysis, and paint additives. In this study, the upgrading of a Nigerian biotite-rich kaolinite ore by a hydrometallurgical route was investigated in oxalic acid media. During leaching studies, the effects of parameters including reaction temperature, lixiviant concentration and particle size on the extent of ore dissolution were examined. At optimal conditions (1.0 mol/L C2H2O4, 75 °C), 92.0% of the initial 10 g/L ore was reacted within 120 min. The dissolution curves from the shrinking core model were analyzed and found to conform to the assumption of surface diffusion reaction, and the calculated activation energy of 33.2 kJ/mol supported the proposed model. The unreacted product (~8.0%) analyzed by XRD was found to contain siliceous impurities and could serve as a valuable by-product for certain industries.