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By J. H. Rushton, L. H. Mahony

Principles of fluid motion and turbulence which have been found to be of use in mixing and agitation problems are discussed, as well as suggested applications in extractive-metallurgy processes. Various types of impellers are described, together with other conditions that affect flow pattern and turbulence. The choice of equipment for particular requirements is considered, and equations for power input are given. Modern heavy-duty mixing and agitation equipment can take an increasingly important part in such extractive-metallurgy processes as solids handling, crystallizing and leaching, chemical operations, and flotation. Application of mixing and fluid-mechanics principles to extraction methods can lead to greater process rates and a resultant saving in time and money. MIXERS are being applied with increasing frequency to problems in the metallurgical industries. The increase represents in part the modernization of mechanical equipment used through the application of unitized drives, modern electric motors and speed reducers, and recently developed materials of construction. Some applications have resulted from process changes and the use of techniques for operations similar to those that have been demonstrated and proven in the chemical industry. Still more applications are being developed through the use of fluid-dynamics principles not previously recognized as applicable to these operations. It is the purpose of this paper to describe those principles of fluid motion and turbulence which have been found to be of use in mixing and agitation problems, and to suggest applications for them in the extractive-metallurgy processes. Modern mixing equipment has been designed to provide the fluid motion consistent with that best suited to different operations.' When properly applied, these more efficient fluid-handling mixers result in lower process-production costs. Metallurgical operations usually involve large amounts of solids. The characteristics of the ore control the process and only enough liquid is added to provide sufficient fluidity for handling and processing. The reactive part of the ore, the mineral value to be extracted, is likely to be low in percentage, and the quantity of reagent required is similarly low, but excessive dilution makes additional reagent necessary and therefore is undesirable. Thus, the primary problems in minerals processing are to handle as high a concentration of solids as possible and to distribute reagents uniformly. These pulps, or slurries, are in a range of solids concentration where hindered settling rates apply, and care must be taken to agitate and mix sufficiently to maintain suspension and flow throughout the equipment. Such slurries have high densities which are the weighted average of the components and viscosities that are spoken of as "effective viscosities" but are difficult to evaluate. It is convenient to separate metallurgical operations involving mixers and agitators into three categories: solids handling, mechanical or physical operations, and chemical operations. In each of these categories fluid motion is required to maintain suspension, to distribute surface-active agents, to blend components and reactants, and to induce high rates of chemical reaction. After a discussion of some basic principles of mixing and agitation, examples of application to the three categories will follow. Fluid Motion The fundamental problems of mixing and agitation of liquids have to do with the mechanics of fluid streams and the means by which they are

Jan 1, 1955

By Jimsher Aneli

The investigation of some peculiarities of conductivity dependence on filler type and amount in the polymer composites has been conducted. It is established, that conductivity of composites based on phenolformaldehide resin essentially depends on proportion of double fillers: graphite + carbon black, graphite+ andesite, contained in composites. It was shown, that these composites characterized by synergetic effect ? non additive influence of fillers concentration on the conductivity of composites. Some other properties of composites contained binary fillers (effect of temperature and pressure on the conductivity) have been investigated.

Jan 1, 2006

By Mroczek C. R, Evans D. A

Renison is a world-class ore deposit that has been mined for over 100 years. It currently has reserves of 5.06 Mt @ 1.88 per cent Sn and a projected mine life of 8.5 years. Recent advances in the geological understanding of the deposit have been associated with detailed structural and geophysical investigations accompanied with the discovery and exploitation of the Rendeep orebodies. Mineralisation is linked to the forceful emplacement of the Devonian Pine Hill Granite that resulted in a complex brittle (-ductile) deformation of the Eo-Cambrian host stratigraphy. Dilation jog development on the Federal-Bassett Fault in the Federal and Rendeep areas provided access for cassiterite-rich magmatic hydrothermal fluids responsible for carbonate replacement Mineralisation.

Jan 1, 1997

U.S. Minerals Coordinating Council Advised. -The Critical Materials Act of 1981, H. R. 4281, introduced on July 27, would create a Council on Critical Materials in the White House Executive Office to oversee Federal materials programs involving $1 billion committed to research by 14 agencies, and to serve as the President's focal point to evaluate materials policy. It was introduced by Congressman Fuqua (D-Fla.) whose Committee on Science and Technology has over-sight over the implementation of P. L. 96-479, the National Materials and Minerals Policy, Research and Development Act of 1980. Bulgaria's Mineral Bank. -Recently Bulgaria established a mineral bank to facilitate receipt of foreign credits for exploiting Bulgaria's mineral raw materials. The bank has wide powers to enter into business arrangements with foreign creditors. Bulgaria's main interest in trading with the West is to import the technology for developing energy and mineral resources.

Jan 1, 1981

By Ulf G. Gwildis

The Bright water Conveyance System includes 21 km of tunnels mined by two earth pressure balance Tunnel Boring Machines (TBMs) and two slurry TBMs. The probabilistic baseline approach defined in the Geotechnical Baseline Report (GBR) can representatively be verified by use of a comprehensive tracking system to identify face conditions that allows comparison with the baselines. The glacial geology includes a high lateral variation in soil types that, when combined with the pressurized face tunneling methods, creates challenges for documenting face conditions. Baseline tracking using spoil samples and TBM operational parameters provides information to document actual conditions and support resolution of differing site condition claims.

By Veerendra Singh, Y. Rama Murthy, Sunil Kumar Tripathy, Nikkam Suresh

"High intensity dry magnetic separation is commonly employed to separate different para-magnetic minerals including mineral sand. Separation in these separators is majorly influenced by the combined effect of gravity, centrifugal and magnetic forces on a particle. These separators are included in the process flow-sheets either for pre-concentration purposes or for the beneficiation of paramagnetic minerals. Separation in these separators is majorly influenced by the difference in the magnetic susceptibility of the associated minerals, particle size and shape along with the process variables of the machine. Particle size is one of the major parameter that plays an important role and decides its probability of selectivity under the magnetic field. However, effect of particle size on the performance of these separators are not well understood which is evident from the literature.In the present investigation, an effort is made to bring out the effect of particle size on particle separation in an induced roll magnetic separator while treating ilmenite fines. Effects of operating parameters, such as; magnetic field intensity, roll speed, feed rate and splitter position have been studied and their influence on particle size has been analysed in terms of yield (wt.%) to magnetic product, particle size distribution characteristics in terms of D50 and D80 size, skewness, kurtosis. Also, the particle size distribution of each test was fitted in Rosin-Rammler equation. The test results were analysed statistically to understand and quantify the influence of each variable on particle separation. It is found that, rotor speed of the separator had maximum influence on yield to the magnetic product whereas splitter position had major influence on D50 and D80 (µm) size of the product."

Jan 1, 2016

By W. J. Douglas

The mine manager in today's environment is faced with a wide variety of problems and challenges which must be addressed if efficient and profitable operations are to be achieved. Expansion of operations has, in many instances, resulted in inexperienced work crews, face supervisors, and superintendents. The complexities of a mining system preclude rapid movement through the learning curve for moat personnel. The management of production suffers both from this inexperience and the lack of standard procedures and methods for planning, schedul ing and analyzing production systems. The lack of visibility of information, as well as of the operations themselves, due to their remoteness, adds to the problem of production management.

Jan 1, 1980

By Omkar N. S. Beruar

Extraction of sill pillars has always been problematic because of high risk of seismicity and rockburst. Depending on a number of factors, a sill pillar can undergo different failure modes and cause problems in the mine. Of these, sudden and uncontrolled failure of part(s) of the pillar leading to highenergy seismic events and rockbursts is a main concern because it is not possible to predict the location and time of a rockburst apart from its potential to cause extensive damage to the mine structures. To date, a comprehensive technique for sill pillar design and recovery does not exist. Conventional methods of pillar design, such as the pillar stability graph method, are utilized to design stiff sill pillars. In these design approaches, the post-peak response of the pillar-rock system is not considered. This is in part due to a lack of clear and comprehensive understanding of the post-peak behaviour and failure mechanism of sill pillars. In general, the strength of a rockmass is described using a failure criterion. When stresses reach the strength of the rockmass, the rockmass does not necessarily become unstable and knowledge of the loads alone is not enough to assess the instability conditions accurately. In fact, it is not possible to predict instability of rockmass based on the strength/stress ratio alone because instability depends not only on this ratio but also on the loading condition and loading system characteristics. The loading system can dictate whether the sill pillar will go through a stable or unstable failure process. This paper examines the influence of various parameters such as the pillar width to height ratio, the extraction rate, and placement of backfill on the Loading System Stiffness (LSS) and the Pillar Stiffness (PSS). The ultimate goal is to design yielding sill pillars that would yield in a stable manner and will reduce the risk of pillar rockburst. Plane strain finite element analysis is conducted using the generalized Hoek-Brown failure criterion with elastic-brittle-plastic parameters. Examples are given to demonstrate how to calculate these stiffness values and assess the stability condition of sill pillars. It is found that increasing the rate of extraction increases the likelihood of unstable yielding of the pillar as has been found in other studies. Placement of backfill in a timely fashion in the stopes above and below the sill pillars increases the stiffness of the loading system. This indicates that backfilling of stopes while creating the sill pillar increases the likelihood of stable yielding of the sill pillar.

Aug 1, 2013

By Clarke P. E

At the end of the recent war, reports became available from Europe of the use of tungsten-carbide inserts in percussion rockdrill bits. These bits were used with small size rockdrills, so that the only advantage gained from the use of the harder, abrasion resistant, tungsten-carbide appears to have been the greater life of the bit. Larger machines, such as used in Australia in conventional practice, had to be discarded to protect the relatively brittle tungstencarbide inserts and the vulnerable bonding with the bit body.As it had been found in machine shop practice that some grades of tungsten-carbide had been produced with considerably improved toughness, it was decided by Gold Mines of Australia Ltd. that drilling practice with tungstencarbide bits warranted detailed examination under Australian conditions, and that drilling tests should be undertaken at Morning Star (G.M.A.) Mines N.L., for which it acts as General Manager and Consultant.These investigations progressed through three stages:1. Preliminary Investigations and Tests.When the investigations were initiated no commercial bits were available in Australia, and manufacture was commenced with improvised equipment from virtual scratch. These early tests indicated that the use of 3 in. bore rockdrills in conjunction with tungsten-carbide insert bits was a 'possibility, and that it was unlikely that a small bore...

Jan 1, 1950

By E. Divers

This Bureau of Mines report presents results of an underground evaluation to determine the respirable dust and gas control effectiveness of a combined (push-pull) face ventilation system for coal mines. The system utilizes both blowing and exhaust curtain, continuous miners equipped with radio remote control, and flight conveyors. Bureau of Mines tests showed a 97% reduction in respirable dust concentrations from the usual cab position on the continuous miner to the remote control operator's position. This allowed the remote control operator to be well within, and the usual cab position to exceed, Federal respirable dust standards. Tests utilizing a safe tracer gas, sulfur hexafluoride (SF6), to determine the face ventilation effectiveness of the combined blowing and exhaust system showed that the system also has excellent methane dispersion capability. Where wide entries permit, this combined face ventilation system and use of remote control can be a very effective method for dust and gas control.

Jan 1, 1982

By K. Hawboldt, J. E. Halfyard, C. Bottaro

The removal of sulfur from leach residues has been practised in the zinc industry using a combination of flotation and hot melt filtration. The process is highly dependent on the nature of the concentrate and the subsequent residue. When the mineral constituency of the residue alters, the process can encounter significant operational challenges. An alternate method of converting elemental sulfur to water-soluble polysulfides was applied to leach residue from Vale's nickel demonstration plant in Argentia, Newfoundland. Reaction parameters, sulfur purity and other key indicators are discussed as is the potential commercial application.

Jan 1, 2011

[Consider a square block W in an ore body S2, to be valued from one centre sample w, and one corner sample w2 (Fig. 9.1). The sample set is ws = Iw,;w21. We can estimate the block average µw by the average of the sample values x, and x2: µw = 'z (x, + xz). (9.1) The error made is measured by the estimation variance: o' (ws to W) = 2 - (ws; W) - - (ws;ws) - - (W; W). (9.2) However, we know that the centre sample w, gives more information about the block value than the corner sample w2. In the example studied in § 8.4, where w, and w2 were considered to be points, we found that of (w, to W) was nearly one third smaller than o2E (w2 to W), therefore when estimating W one should give more weight to w, than to w2. In general, when evaluating a block W from a set of n samples ws, where WS = l w;w2; ... wn1, a better estimator of µw can be obtained if we give different weights to the sample values, depending on the size and the positions of the samples. Some desirable properties of such an estimator µw are: ? It should be a linear function of the sample values xi: n µw = bi xi (9.3) =t where bi = weight given to sample x . ? It should be unbiased, i.e. its expected value should be equal to the true block value: E [µw - µw] = 0. (9.4) ? The mean squared error of estimation of µw should be a minimum E [(µw - µw)2] = a minimum. (9.5) The estimator which satisfies these properties is a minimum variance, linear and unbiased estimator, and is known as the kriging estimator. The corresponding error of estimation is the kriging error. This estimator is also known as the BLUE (for Best Linear Unbiased Estimator) estimator. This was named by Matheron in acknowledgement of the early work of Krige's in the optimization of the evaluation of the South African gold mines. The following notations will be used: µK kriging estimator. o2k = o2K (w,, to W) kriging error.]

Jan 1, 1978

By S. Kelebek

DETA exhibits a highly selective depressant action on pyrrhotite without adversely affecting the collectorless flotability of pentlandite and chalcopyrite in nickel-copper ores of the Sudbury region. A simplified Eh-pH diagram has been constructed to illustrate the extended stability of elemental sulphur and to explain the collectorless flotation of pentlandite and chalcopyrite. Cu and Ni ions, which are known to exist on the surface of pyrrhotite, promote the flotation of this mineral whether a collector is present or not. Thermodynamic calculations indicate that the action of DETA involves the sequestration of Cu and Ni ions from surfaces under a wide range of redox conditions; analysis of flotation test filtrate indicates as much as a 20-fold increase in the concentration of Ni and Cu ions. It appears that DETA may enhance the self-hydrophobicity of chalcopyrite and pentlandite by exposing more of the sulphur-rich surface sites for bubble contact in flotation. There are various possible explanations for its depression of pyrrhotite

Jun 18, 1905

By W. E. Anable

The Bureau of Mines researched methods for recovering copper from cyclone and electrostatic-precipitator dusts of primary copper smelters as part of its program to maximize minerals and metals recovery from primary and secondary domestic resources. Small-scale studies showed that use of 110 pct stoichiometric sulfur and 123 pct stoichiometric carbon, based on producing a 40-pct copper-iron matte, resulted in the recovery of 95 pct of the copper contained in the dust. Typical mattes contained less than 10 pct of the arsenic, 30 pct of the bismuth, and 45 pct of the antimony and tin contained in the dust. Matte was converted to blister copper by injecting up to 200 pct of the stoichiometric oxygen requirement over a period of 2 to 3 hours. Up to 76 pct of the copper contained in the dust was recovered as a crude blister copper containing about 2 pct arsenic, 0.5 pct antimony, and less than 0.1 pet bismuth and tin. A matte-white metal product resulted from carbothermically reducing dust with coal, lime, and silica. Up to 95 pct of the copper was recovered in the combined product.

Jan 1, 1981

By Robert Moore Lewis

A unit for separating minerals Into two prescribed size fractions, designated as a Lewis Hydrosizer, was developed at the North Carolina State University Minerals Research Laboratory Ore samples with different mineral compositions, including coal, were separated effectively with the laboratory continuous unit Commercial size units are in operation in North Carolina and Mexico, and under construction In Norway Additional units are being built or are in the planning stage at several companies.

Jan 1, 1983

By T. S. Smith, C. C. Rennie

"THE LEAD-ZINC and tungsten mines of Canadian Exploration Ltd are on Iron Mountain, 8 miles south of Salmo, B.C., in the Nelson mining division. Relative location of the mines is shown on the general plan.First recorded lead production was in 1908 from surface outcrops. Small amounts of high lead ore were mined intermittently until 1926. No major lead-zinc production occurred until 1949 when outcroppings on the south side of the mountain were mined and diamond drilling began to prove the existence of a large replacement orebody. Lead-zinc ore has been mined continuously from the Jersey orebodies since March 1949, with monthly tonnage as high as 50,000 tons per month, but currently averaging 30,000 tons per month.Schee1ite-bearing tungsten ore was found in 1942 by H. Lakes in an old adit and open cuts at the north end of the Emerald tungsten orebody. The Emerald tungsten mine was developed by the Federal Government as a Wartime Metals project and operated for eight weeks in the fall of 1943, when the poor demand for tungsten closed the mine. Canadian Exploration Ltd. purchased the mine in 1947 and mined in excess of 100,000 tons in 1947-48 until the demand for tungsten dropped again and interest was centred on lead-zinc. The Federal Government repurchased and reopened the Emerald Mine in 195 L and built a new concentrator. The mine and mill were sold back to Canadian Exploration Ltd. in 1952.Regional Geology and IntrusivesThe host rock for both the lead-zinc and tungsten mineralization is the Laib formation of Lower Cambrian age, which consists of 400 feet of crystalline limestone underlain by beds of argillite, and argillaceous limestone locally altered to ""skarn"" or ""tactite"". The Laib limestone is overlain by black argillite and underlain by the Reno quartzite of Pre- cambrian age. Repetition of folded beds has allowed the interpretation of the large isoclinal fold which repeats the limestone (see general cross-section). Dolomitization and the associated lead-zinc ore have been found only in the right-side-up limestone and are not known in the overturned limestone.Two elongated stocks of granite cut the sediments. The Emerald stock outcrops along the east side of the Emerald tungsten mine and again west of the Jersey workings, while the Dodger stock outcrops only at the north end of the Iron Mountain. The shape and attitude of these bodies are believed to have been governed partly by pre-granite faulting and partly by pre-granite folding of the sediments. Although some forceful intrusion may have occurred the detailed granite surface indicates a gentle stoping emplacement."

Jan 1, 1949

By L. C. Armstrong

A. E. ROSS*—Mr. Armstrong in his paper stated that they had experienced considerable difficulty in drilling the quartz-feldspar intergrowths. The dia-mor~d loss was excessive and the diamond bits polished quite rapidly. Mr. Davidson, who presented the paper, stated that bortx stones in the range of 20 to 30 per carat had been used in the bits on this job. I would like to suggest the use of bits employing stones in the range of 60 to 100 per carat, an average of possibly 80 per carat. If these stones had been used the bits might have lasted longer and not polished so quickly. As a basis for this suggestion I would like to point out that in northern New York State we had at least two examples where bits employing stones in the range of 80 per carat had solved a difficult problem. Bits set with stones in the range of 20 to 30 per carat had been used previously and had failed. With the finer stones, the cost per foot of drilling decreased material1y. It should also be noted from a technical standpoint that the smaller stones require higher drilling speeds than the larger stones. Greater pressures are not normally necessary, and it is the higher speed which seems to be the major factor of importance. It should also be noted that the finer stones afford a greater number or cutting surfaces for the same carat weight in a bit. Then too, the smaller stones, by virtue of their size, serve as sharper cutting edges than larger stones. There is no doubt that the diamond bit employing smaller stones costs more to set than the bit using larger stones. However, with the technique developed at the shops of Sprague and Henwood, Inc., we feel that the relatively slight additional cost required to set these bits is more than paid for by the resultant lower drilling cost. We feel that the highest quality stone available is the most economical to use when hard fine grained rock is encountered. In summary, I would suggest that it might be possible to solve the problem presented in this paper by using a diamond bit employing stones at least as small as 80 per carat of the highest grade possible and by using the diamond bit at the highest speed available with modern drilling equipment. L. C. ARMSTRONG (author's reply) —It is generally agreed that the use of smaller, high-grade diamonds and of higher drilling speeds, as suggested by Mr. Ross, may be the best approach to the solution of the problem.

Jan 1, 1950

By Engineering Staff

"This paper briefly describes the surface mining operations at Smoky River Coal Limited (formerly McIntyre Mines Limited, Coal Division) near Grande Cache, Alberta. Geology, mining methods, equipment, manpower and reclamation and environment topics are discussed. Introduction Smoky River Coal Limited, a wholly-owned subsidiary of McIntyre Mines Limited of Calgary, Alberta, produces a high quality, low sulphur, low volatile bituminous coking coal from its minesite located at west central Alberta, approximately 20 km from the town of Grande Cache and 360 km west of Edmonton (Fig. I). Most of the coal property is contained within a 30 km long by 20 km wide block lying in a northwest-southeast direction in mountainous terrain. Elevations vary from 920 m above sea level ·at the plant·site on the Smoky River to 1,600 mat the upper levels of current and proposed mining operations. A total of 11 coal seams have been identified. Only two seams, No. 4 Seam and No. 10 Seam are currently considered of major commercial value. These seams are recovered by both surface and underground mining. Approximately 650Jo of the plant feed coal is obtained from a conventional shovel/truck surface mine; the balance is mined underground by room-andpillar methods. Background In 1921, McIntyre Mines Limited acquired some 26,300 hectares of coal leases at Smoky River. Since then the leases were explored intermittently by different companies including McIntyre. In the mid-l 960s exploration activities increased and several feasibility studies were completed. Development of the area was undertaken by McIntyre in 1968 and, in August of the same year, a long-term contract was signed with a consortium of Japanese steel mills for delivery of 2 x 106 t of clean coking coal for 15 years commencing in 1970. Production was focussed on underground mining, using longwall methods."

Jan 1, 1985

By S. Z. El-Tawil, K. A. El-Barawy, M. B. Morsi, M. M. Nasr, Z. I. Zaki

"Tue sulphatization of zinc concentrate produced from heated zinc concentrate of Um Ghieg area, eastern desert by ammonium sulphate as sulphatizing agent is carried out at different conditions to achieve the appreciable formation of soluble sulphates. The maximum zinc recovery as soluble sulphate equfils to 95% upon using 1.5 stoichiometry ammonium sulphate at 600 °C for one hour. Tue obtained leached zinc sulphate solution is subjected· to purification process to prepare high pure zinc metal and zmc compounds such as pure zinc sulphate, zinc caibonate and zinc oxide. The products obtained are analyzed chemically and identified by X-ray analysisTue mechanism and kinetics of the sulphatization process of zinc concentrate are considered where the activation energy is calculated and equals to 33.3 K.J.mol""1 A process flowsheet for the overall sulphatization process of zinc concentrate by ammonium sulphate is proposed.IntroductionConsiderable reserves of zinc ores are present in Um Ghieg area eastern desert, Egypt. The possibility of extraction zinc from these ores and preparing its valuable compounds by choosing a more feasible technology become of vital importance. An attention is focused on the sulphatizing roasting processes (1-9) to achieve the appreciable formation of soluble sulphates. Previous publications are reported in our division by El. Tawil and others (10-16) using ammonium sulphate as sulphatizing agent for the successful treatment of nonferrous bearing materials.Therefore, the present work aims to study the different factors affecting the sulphatizing roasting process of local zinc coocentrate by anunonium sulphate to extract completely zinc and preparing its main compounds. Tue mechanism and kinetics of the different chemical reactloos that 1ake place in the process are considered."

Jan 1, 2000

THE only asbestos mine in the Middle East is on the Island of Cyprus, high in the Trodos Mountain village of Amiandos. The mine is owned by the Tunnel Asbestos Cement Co. Annual output is some 18.000 tons of short fibre in the 4-T. 4-Z, and 5-R grades.

Jan 9, 1953