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By Jacolien P. Wyethe

Zincor uses a Roast-Leach-Electrowinning circuit to process zinc sulphide concentrates. It also processes zinc oxide fume, originating from a slag smelting operation in the Democratic Republic of the Congo (DRC). Zincor achieved an average zinc recovery of 90.3% during the period January 2006 to May 2007. The bulk of the losses occurred in the iron and lead silver residues, both as soluble and un-dissolved losses. The un-dissolved losses in the iron residue constituted around 33% of the total zinc lost from the circuit, and were largely attributed to the presence of zinc-ferrite in the calcine used for neutralization during iron removal. As part of Zincor?s continuous improvement programme, the un-dissolved zinc losses in the iron residue were targeted by: the partial replacement of calcine with zinc oxide fume (from the DRC); and the preferential use of ?low-ferrite content calcine? as neutralizing agents in the iron removal circuit. These initiatives, coupled with other operational factors, resulted in a marked improvement in recovery to 92.6% during June to December 2007. The zinc oxide fume, directly fed to the circuit, required investigation of the halide rejection capacity of the Zincor circuit. Rejection of chloride via the magnesium bleed operation was considered adequate. Fluoride was mainly rejected via the iron (~70%) and lead silver (~27%) residues. Fluoride rejection via the lead silver residue varied significantly, probably as a result of variations in the sparingly soluble CaF2 content in the feed. The mechanism for fluoride rejection in the iron residues is uncertain. The fluoride rejection capacity of the Zincor iron residue (comprising of mainly jarosites, schwertmannite and ferrihydrite) at 2 ? 4 mg/L F in solution, was estimated at 0.14 ? 0.19 kgF/tFe residue.

Jan 1, 2008

By R. A. Lord, H. M. Prichard

efficiency is discussed from both experimental and

Apr 1, 1994

By Parker A. J, Ruane M, Wadley L. G B

Copper, sulphur, nickel, cobalt, palladium, silver, and gold can be recovered from the copper sulphide precipitated from the "copper boil" of the Sherritt-Gordon nickel process used at Western Mining Corporation's Kwinana nickel <refinery. The method is based on an oxidative ammonia leach of copper, nickel, and the precious metals at temperatures below 40°C to produce, in part, elemental sulphur, in the residue. This is followed by heating to decompose thiosulphate and remove some ammonia with precipitation of some of the copper, palladium, gold, and silver. Addition of sulphur dioxide to pregnant liquor precipitates copper, as either Chevreul's salt or copper(I) ammonium sulphite, together with the remaining gold and silver. Less than 10 per cent of the dissolved palladium and less than 1 per cent of nickel and cobalt precipitate to this stage.In one option, the Chevreul's salt is dissolved in a solution of copper(II) sulphate, acetonitrile, and water to generate a solution of copper(I) sulphate. Gold and silver do not dissolve. The solution of copper(I) sulphate is thermally disproportionated by distilling acetonitrile to give exceptionally pure copper powder, with desirable characteristics for powder metallUrgy. Nickel, cobalt, and ammonium sulphate are recovered from the motherliquor of the Chevreul's salt precipitation by return to the Sherritt-Gordon process, where recovery procedures already exist. Palladium is recycled for eventual removal as a sulphide with the gold and silver.In the other option, solid copper(I) ammonium-sulphite is <thermally disproportionated in water at 150°C to copper powder.

Jan 1, 1978

By R. W. Vieth, S. A. Bradford

THE orientations of tetragonal tin crystals are commonly examined by either the transmission Laue method or the back-reflection Laue method. The predominant planes and zone axes of the pattern are plotted on a Wulff net and indexed by measuring the angles between planes and directions. The problem of identifying the Laue spots has been approached in several different ways. Nicholas 1 tabulated interplanar angles for ten planes but did not relate the angles to permutation of indices or sign. A table of angles between adjacent planes and of angles between adjacent zones was published by Chandrasekhar and veal.' These tables are very helpful, provided the film shows all the low-order zones that occur within about 20 deg of each other. Frounfelker and Hirthe's compilation3 of angles between the (001) plane and twenty-nine other planes is useful for the indexing, only if the (001) spot can be found on the film. For all but the simplest orientations, however, more information is needed to index the diffraction spots. Standard stereographic projections, such as those published by Bicelli, 4 provide part of the information required. By their nature, these projections show the positions of only a few zone axes. In the tetragonal system many low-order zone axes are not normal to the planes having the same indices. Consequently, planes and directions can have entirely different positions on a stereographic projection. For example, the [011] zone axis is 33 deg from the normal to the (011) plane. The crystallographic orientation usually has to be deduced from a combination of the predominant zone axes and a few low-order planes that appear on the film. In addition to a standard stereographic projection of the planes, a stereographic projection of the directions is needed. Such a projection can be constructed from the angles given in Table I. To provide more information about angles between planes and directions, we have calculated interplanar angles up to (332) and angles between planes and directions up to [332] on an IBM 1620 computer. The angles are differentiated according to permutations of sign and indices. Those doing research on tin single crystals are welcome to request a copy of these tables from the authors.

Jan 1, 1967

By E. R. Maize

[In %-port of Invcstiptionn 7452 ,g dcniing with roof ~wet,ent in the Cmcibla r~ine, rof&apos;erence .,as m.da to the f~ct tiwt timker decny war, bsing studied at tho tine of writing. Thic napor, written a3er completion of that ~tudy, describ~s t1l.e ~mrl&apos;: and sunlharizea the fiats obtained. Ifhen tlle stu* oi roof novement bras be,- at Cxcible tw igeas \%.ere a6-r;incsd. on decay of tiriber Q: scne of :he olficialr;: (I.) 9:la.t timber decay v:as unustmlly rapid in ,tho Ciuoiblc mins, ,m?. ((2) that timber coated with rock ri..~st deixiyad morrl mpirlly thnn those %hat vsrc not so coated. Thsx ::ore no records by which tkeso &apos;iaeas could &apos;L;e tertcc?, ard it cnpsarefi vise to make a limite6 in- vo3tiption, p~.rticu!.ai.ly of +.he effect of roc!< dusting on decny, as rock ductirg is nn importnnt mer-ns of ~rc-,rcnt?;~g cad-dust eql-osions. ]

Jan 1, 1941

By A. Tor, M. Borowski, N. Szlazak, D. Obracaj

This article presents possibilities of reducing methane emission to the atmosphere in working mines in Jastrzebie Coal Company by means of proecological solution. They form a new approach towards the problem of rational and effective use of natural resources both in economical and environmental respect. Power and thermal energy for underground air conditioning in mining excavations are produced from the methane, which is drained out of the mine for safety reasons.

Jan 1, 2003

By J. J. Dowd

1. The Pittsburgh bed is the most important bed in Marshall County, and virtually the entire production of coal in the county comes from this bed. 2. Known measured and indicated reserves in all beds, based on a minimum thickness of 14 inches and 1,800 tons per acre-foot of coal in place, were estimated at 3,158 million short tons as of January I, 1954. Of this total, 3,071 million short tons is in beds 28 inches and more thick. Areas in each bed except the Pittsburgh were omitted from the estimate because available data relative to the bed characteristics are too meager to make an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves.

Jan 1, 1956

By J. T. Nel

The establishment of a pilot plant for the continuous production of titania pigment and nano-titania is discussed. The plant was designed, constructed and operated on the Necsa site. The TiO2 production capacity is 7?10 kg.h-1 by the reaction of TiCl4 and O2at>1000°C. Liquid TiCl4 is sprayed under pressure into a plasma reactor where it evaporates and reacts with O2 to form TiO2. Process optimization has allowed for continuous production without any clogging or blockages. The primary advantage of the plasma-assisted process is the possibility to recover and recycle the chlorine values in high yield as Cl2 for use in the manufacture of TiCl4. The HCl formed in most conventional fossil-fuelled processes makes Cl2 recovery and recycling much more difficult. Particle size distribution analysis of the fine, white product revealed a d50= 125 nm. The raw product consisted of 60% rutile that could be increased to 80?100% rutile by post-annealing. The specific surface area (SSA) of the pigment was 8?20 m2?g-1(BET). According to the CIE colour index the ?whiteness? (L*>95) of the plasma-produced pigment was better than that of several commercially available pigments. The particle size could be manipulated by controlling the TiCl4 feed rate, gas flowrates, and the particle quench rate and residence time. Nano-sized TiO2 powders with a particles size (d50) as small as 50 nm were also successfully produced in this way.

Jan 1, 2010

By Louis E. Dalverny

U.S. Bureau of Mines research to develop diagnostic methods to locate and evaluate fires in abandoned mines and waste banks and techniques to extinguish such fires was applied to an abandoned 60-acre underground bituminous coal mine (Renton, Allegheny County, PA) to locate and extinguish three separated fire zones. Mine fire diagnostics interpret changes from baseline values in subsurface pressures, temperatures, and mine gas composition under imposed pressure gradients induced by a borehole exhaust fan. The effective gas sampling area surrounding each borehole is greatly enlarged. Sampling iterations, using a "communicating" boreholes set, provide "fire signature" information for locating both heated and cold areas. Time-dependent monitoring differentiates heating and cooling periods resulting from combustion front movement and/or fire extinguishment activities. A water injection with fume exhaustion extinguishment effort involved injecting water through boreholes to quench the heated zones while exhaust fans actively removed heated gases from the mine. The technique was ineffective as implemented, primarily because of inadequate spreading of water from the injection points. The Bureau&apos;s diagnostic method determined the fire locations and the effectiveness of the water injection with fume exhaustion extinguishment technique.

Jan 1, 2010

By M. Kanefsky

Two channel polarity coincidence and polarity difference statistics are analyzed. The signal, common to both channels, consists of sinusoidal bursts where the exact frequency of the signal is nearly known, but other parameters such as amplitude, phase, and pulse starting time are unknown. The noise inputs are dependent, narrow band, Markov processes. It is shown that the performance depends not only on the signal uncertainties, but on the precise shape of the cross-correlation functions between the noise in-puts. By using two polairty difference statistics in addition to the polarity coincidence statistic, it is shown that the decrease in performance, as well as the cost of hard limiting due to correlated inputs, can be made small.

Jan 1, 1981

By C. J. Greet

Grinding with an electrochemically inert grinding media (i.e., high chrome white iron) shifts the pulp potentials to more oxidising conditions, increases the dissolved oxygen content and reduces the EDTA extractable iron concentration when compared with milling with electrochemically active grinding media (forged steel). These changes in pulp chemistry produce cleaner particle surfaces, reduce reagent consumption, and increase concentrate grades and recoveries. This paper presents a robust laboratory test program that not only demonstrates the changes in the pulp chemistry, but also provide an indication of the magnitude of the metallurgical improvements that are possible. While laboratory studies are interesting, the proof is in the pudding! So, the paper provides an overview of plant trials conducted at several porphyry copper operations around the world: Newmont’s Cadia and Red Chris Operations, as well as Evolution Mining’s Northparkes Operation. These successful plant trials clearly demonstrate that selection of the right grinding media alloy will yield savings in grinding media consumption and reagent consumption as well as increases in revenue through improved copper and gold recoveries. However, many of the porphyry copper mines on the Eastern Pacific are copper-molybdenum deposits. The paper presents laboratory test results for typical copper-molybdenum operations and extrapolate these numbers to what might be expected should a plant trial occur.

Feb 1, 2025

By D. E. Sherwood

Recent developments in high torque hydraulic rotary rigs has lead to the construction of secant bored pile walls by rotary drilling methods in circumstances where earlier methods were difficult and in some cases impossible. The evolution of secant bored pile wall construction is described including classical, rotary drilled and continuous flight auger construction methods. The paper then details the restraints which have been created in recent inner city redevelopment, many of which were not relevant in the early days of the technique. Typical examples of walls are presented to show the adapatability and advantages of the secant bored pile wall method. A number of in-situ retaining wall construction techniques are then compared in detail with regard to relative cost, technical quality and practicality.

Jan 1, 1989

By Sam S. Taylor

[The discovery of many oil fields in Illinois since 1936 and their rapid development have brought tine problem of brine disposal to the foreground in that State. The ultimate magnitude of the is not yet known, but already it is great enough to warrant technical investigation. The Bureau of Mines, therefore, has made a general survey of the methods of handling oil-field brines in Illinois and has studied in detail three subsurfaces disposal systems.]

Jan 1, 1940

By Rodney R. Koch

The phys ica l properties of gold should faci li tate its detection. However, the average concentration of gold in the ea rth's cru st precl udes the ability of geophys ical methods to detect the metal directly. In order to effectively pursue geophys ical detection and location of gold mineralization there must also be geological input - i.e. a model. This will lead to the selection of the appropriate geophy ical techn ique(s) in the fo llow-up programs. Interpretation of the fie ld survey data is of con iderable importance in expl oration geophys ics. Analytical techniques such as cont inuation, fi ltering, and spectral analys is, are now routinely empl oyed in the analys is of survey data to aid the interpretation process. The uccessful application of geophysical methods and the use processing techniques is demonstrated by two recent Saskatchewan discoveries. The first, the Star Lake 21 Zone, with reserves of 230,000 tons grading bener than 17.14 git Au associated with a disseminated sulphide quartz-bearing shear zone yielded geophysical anomalies that were distinctive, obvious, and would have lead directly to its discovery. The econd , the Laurel Lake Prospect, with ore grade intersections of 28.0I git Au and 52 .46 git Ag· over 5.49 m, resulted in numerous geophysical anomalies. However, none of these anomalies demonstrated association with the mineralization until processed results indicated that structural features crosscuning regional trends were important cont rol mechanisms for the mineral ization.

Jan 1, 1986

By Oliver Bowles

The United States Bureau of Mines has within its ranks a group of engi- neers who are engaged in working out quarry problems, the solution of which will be of general benefit to the industries involved. The problems undertaken are approached in a systematic and thorough manner, all the evidence for and against any proposed change or new development being collected as carefully as an attor- ney would prepare his data on an important case. Unlike the attorney, however, the Bureau engineer does not take sides; his judgment is based entirely and in- partially on the array of facts presented. In order to gain the desired infor- mation he visits many plants, consults with the leaders in the industry, works out experiments in his laboratory, and supplements this information with a stu- dy of all available literature already published on the subject in any part of the world. As an engineer who has for eight years conducted such inquiries in the stone industry, I propose to discuss the Bureau of Mines viewpoint; and it may be of interest to consider with me in a brief and general way the engineer's method of looking at quarry problems, and some of the results attained through past and present labors. While the Bureau has conducted no investigation directly for the crushed- st one industries, two years of investigative work at cement-plant quarries, and work now being conducted at lire-plant quarries, has a very direct bearing on the problems of the crushed-stone industry, since stripping, drilling, blasting, loading, and transportation are similar in many respects in all stone quarries. The results of cement-plant quarry investigations are to be found in Bureau of Mines Bulletin #160. (b) Two short papers on lime-plant quarry problems have been issued in mimeographed form as Serial #01 (c) and Serial 3 (d).

Jan 1, 1923

By Elizabeth M. Smith

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

Jan 1, 2009

By Chunhui Zhang, Enton Bedini, Jiang Chen, Fengchao Yang, Hang Dong, Xiaoyan Chen

The alteration formed by the reaction of ore-bearing fluid and wall rock is often used as an important prospecting indicator, resulting in the dilution or enrichment of metals or related trace elements. A variety of rock-forming and metallogenic elements have been analyzed in regional stream sediments so that the relationship between the ore-bearing altered rock and the change in the geochemical elemental content can be obtained. Therefore, by using appropriate models, such as matched filtering, the abundance of the distribution of wall rock alteration, similar to the discovered deposits, can be modeled by using the distribution of geochemical elements in the region, and the areas with high distribution abundances are usually favorable prospecting targets. The alteration types related to gold mineralization in the Baiyun gold deposit are potassium feldspar alteration, silicification, pyritization, sericitization, and chloritization. In this paper, the geochemical data of the Qingchengzi ore field (1:200,000 and 1:50,000) have been used to form geochemical images through rasterization. In the three sections of the Baiyun gold deposit, binary-coded curves have been formed, revealing the differences in geochemical elements in stream sediments between altered rocks and the rocks surrounding the Baiyun gold mine. Among them, Au, W, and Mo are enriched elements, while Sn, Zn, and Hg are depleted elements. Several gold deposits are found in the predicted altered rock area by using the matched filtering method during fieldwork, which shows the effectiveness of the method.

Dec 30, 2023

By Douglas B. Silver

Traditional cycle theory would postulate that if you have a supply shortage relative to demand, the price will increase because buyers will incrementally increase the price they are willing to pay to ensure that their needs are fulfilled. As prices rise, more supply will be brought on and will eventually exceed demand. This supply excess will cause the price to decline as producers have to lower their prices to sell their goods. What is interesting is that cycles are simply volatility over time. Without the time factor, volatility simply goes up and down. When we add the time element, a cycle is created. This cycle can be big or small. In mining?s case, we are talking about a Super Cycle ? a big cycle. But a Su-per Cycle can be formed in two ways. It can form by either increasing the wavelength or the volatility. If these two elements are combined, a Super Cycle is formed. It is bigger than the normal cycle in terms of time duration and extent of volatility. A recent study (Fig. 1) conducted by Cuddington and Jarrett showed an interesting proof of Super Cycles and suggests that these cycles last between 15 and 30 years. So, what causes a Su-per Cycle? Is it a convergence of unrelated events or a consequence of related events? In a global community everything is related. Equilibrium theory would also take the position that a Super Cycle is a consequence of events.

Jan 1, 2008

By P Mulvey

"Currently mine process studies and geochemical waste characterisation are considered as two interdependent studies, necessary for the development of the mine and inclusion in the environmental impact statement (EIS). Geochemical waste characterisation will utilise the simulated tailings produced by the mine process studies team to understand the behaviour of the tailings, but the two teams rarely integrate these to develop a coherent and agreed final design.Thorough mine waste geochemical assessments can develop processes to minimise environmental harm, resulting in substantial savings in the decommissioning, closure and rehabilitation phases, and may also be able to address changes in mineral processing methods that can result in substantial savings in process inputs, or even recovery of metal concentrates.Based on geochemical waste characterisation, the full cost of waste management can be calculated and incorporated into the costing of milling.&nbsp; This allows for a more effective evaluation of the metallurgy.&nbsp; A number of examples are presented in which substantial improvements have been made from the collaboration of both the metallurgical and geochemical teams during planning and the metallurgical team and environmental team during operations.*This paper is only available for individual download. It is not included in the conference proceedings*CITATION:Mulvey, P, 2013. Optimising metallurgy at the planning stage to minimise environmental impact -&nbsp;a feedback loop from geochemical waste characterisation, presented to MetPlant 2013 Conference (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 15, 2013

Individual specimens of sphalerite from the Broken Hill lode vary considerably in manganese and iron contents, even within the same orebody, so that study of the overall variation of manganese and iron content of the sphalerite calls for the analysis of a large number of specimens. This difficulty has been overcome by analysing a series of recleaned zinc concentrate products, prepared from stope samples and their equivalents, from most of the developed sections of the lode. The analyses reveal that during the formation of the sphalerite the concentrations of iron, manganese and zinc in the mineralizing solutions varied independently of one another from place to place in the forming orebodies, and also in time.The overall pattern of variation of the iron and manganese contents of the sphalerite in the several orebodies of the lode bears a general resemblance to the overall pattern of distribution shown by several other elements, notably, cadmium, lead, bismuth and arsenic. The iron content of the sphalerite indicates that it was formed at a temperature of 6000 C. or higher, but the variation in its iron and manganese contents demonstrates that Kullerud&apos;s method for determining the temperature of formation of sphalerite from its iron content must be used with caution if only single specimens of sphalerite are available.INTRODUCTIONThe four chemical analyses available of specimens of practically pure sphalerite from the Broken Hill lode (Table 1) reveal that the manganese content of the sphalerite varies considerably, and that there is a significant variation in its iron content. The variations revealed between individual specimens within the same orebody in the same mine suggest that specimen material is unsatisfactory as a basis for studying the overall manganese and iron contents of Broken Hill sphalerite, unless a great number of specimensis analysed.

Jan 1, 1956