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By Q. Shi, Q. Feng

"The influence mechanism of chlorite on the flotation of pyrrhotite was investigated through flotation tests, Zeta potential measurements, optical microscope photos, solution ion measurements and absorption measurements. It is observed that, the addition of chlorite influences the flotation of pyrrhotite seriously. The IEP (isoelectric point) of pyrrhotite and chlorite is 7.6 and 4.3 respectively, in the condition of slight alkalinity, both pyrrhotite and chlorite are negatively charged, and the hetero-aggregation will not occur. With the existence of oxygen in solution, the iron ions are dissolved from pyrrhotite surface because of the oxidation of pyrrhotite during pulp conditioning. The dissolved iron ions adsorb onto the surface of chlorite in the forms of iron hydroxyl and iron hydroxide, and the adsorption results in the opposite charge of chlorite surface. As a result, the hetero-aggregation between pyrrhotite and chlorite occurs. The adsorption of chlorite changes the surface property of pyrrhotite and restricts the adsorption of amyl xanthate onto pyrrhotite surface, and then decreases the flotability of pyrrhotite.INTRODUCTIONIn sulfide ores processing, magnesium silicate bearing gangue minerals often report to the concentrate causing downstream processing problems as well as increased smelting costs. Talc,chlorite and serpentine are gangue minerals commonly encountered in complex sulfide ores (Engel, Middlebrook, & Jameson, 1997; Pietrobon et al., 1997; Witney & Yan, 1997; Chen, Grano, Sobieraj, & Ralston, 1999a, 1999b; Bremmell, Fornasiero & Ralston, 2005; Senior & Thomas, 2005; Wang, Somasundaran, & Nagaraj, 2005; WieseHarris & Bradshaw, 2007). All of them are characterized with uniform crystal structures consisting of silicon-oxygen tetrahedron and magnesium-oxygen octahedron. The magnesium-oxygen octahedron layers are broken during the liberation of serpentine to expose the magnesium-oxygen bonds with strong ionicity and hydration, which results in natural hydrophilicity of serpentine. In water, the hydroxyl on serpentine surface ruptures and dissolves into the aqueous phase while the Mg2+ remains, resulting in surface positive charge (Tao, 2012). As serpentine has a positive potential at alkaline condition, it is therefore likely that it will attach through electrostatic attraction to the negatively charged mineral surface and reduce both the flotation rate and recovery of target minerals (Lu et al., 2011). For talc, characterized as good natural hydrophobicity, the liberation comes from the interlaminar fracture to remain molecular bonds on surface with weak hydration. Being naturally hydrophobic, talc easily reports to flotation concentrates, thus reducing concentrate grade (Shortridge, Harris, Bradshaw, & Koopal, 2000; Beattie, Huynh, Kaggwa, & Ralston, 2006). Meanwhile, both molecular bonds and magnesium-oxygen bonds are exposed on chlorite surface when liberation occurs, resulting in moderate natural hydrophobicity between serpentine and talc (Tao, 2012). And thus the mechanisms of influence of chlorite on sulfide ores are more difficult to study."

Jan 1, 2016

By K. Raht

LEAD poisoning is perhaps the oldest and, until recent years, the most misunderstood of all industrial diseases. Hippocrates appears to have recognized a relationship in the colic experienced by a patient who worked with metals, and the ancient literature is filled with references to the colics and 'dry bellyaches'. The colic and other sequalæ following drinking of lead-bearing waters and, particularly, wines has excited possibly more comment in the older medical literature than any other ætological factor. It was not until1656, when Stockhusen definitely connected the colic of the workmen with the fumes given off in the process, that the true danger to those working with lead was recognized. Unfortunately, something over 200 years elapsed before industry took any note of Stockhusen's discovery; it remained for Legge and Goodly and investigators of the early 1900's to forcibly educate their profession and industry to the manner in which lead gained entrance to the body. The work of Legge and Goodly was published in 1912 and the clearness with which these investigators presented the scientific data which they had accumulated will mark this volume as perhaps the first and most important contribution to our modern knowledge of the subject. It also ushered in a period when, in the short space of thirty years, lead poisoning has been reduced from one of the most baffiing and widespread o industrial diseases to one which can be anticipated and controlled. The next great contribution came in 1926 with the publication of the work of the Harvard group. Here, for the first time, was the physiological behaviour of lead laid bare, and it is to the discoveries of these authors that we owe our modern treatment of lead poisoning.

Jan 1, 1941

By J. Béland

"Three stages, each characterized by a particular sedimentation, magmatism, mineralization and deformation, are recognized in the geological history of Gaspe. The first stage led to the formation of the Taconian orogen, the second to that of the Acadian orogen and the third stage to the accumulation of a post-orogenic cover. The Taconian orogen includes volcanic and detrital rocks of Late Precambrian or Cambrian and Lower to Middle Ordovician ages in which ultrabasic intrusions have been emplaced. Folding is severe. Mineralization is of the Cr-Ni-Cu type, related to the igneous facies.The rocks constituting the Acadian orogen include two distinctive sequences corresponding to two successive sub-stages. The second substage began in Early Devonian time with the first pulses of the Acadian orogeny. The rocks of the first substage grade southward from a nearly platformal sequence to an assemblage implying less stability and spotty volcanism. The second substage was one of synorogenic deposition of elastic rocks, first in a marine environment and later under terrestrial conditions. Granitic intrusions, surrounded by aureoles of skarn and hornfels in which Cu-Pb-Zn mineralization is found, accompanied the Acadian deformation. The second-stage"

Jan 1, 1969

By J. H. Archibald

"This paper describes the use of vector analysis for determining the intersection of mineral deposit veins. The mathematical evolution of the analysis is outlined.IntroductionMany mineral deposits can be characterized by sets of intersecting veins. Often a vein will have a steep dip and may intersect with another similar vein. Finding the intersections of these veins is usually done by graphical means. Structural geologists, by the methods of descriptive geometry, can usual ly predict where intersections of veins will occur. This method normally requires accurate drafting and layout of the problem and does not always lend itself to solution in the field.Another method for solving this problem involves the use of vector analysis, which is easily adapted to hand-held programmable calculators. It is assumed at the outset that the reader is familiar with the dot and cross products used in vector analysis. Two excellent references are cited at the end of this note for convenience.A plane, in general, is defined by three points. The points of interest here are the points where three vertical drillholes penetrate the vein, or plane, in question. The elevations of these three points are best referred to sea level. This requires knowing the elevation of the collar of the drillhole above sea level and the drillhole depth from the collar to the vein. The elevation of the intersection point is then found by subtracting the hole depth from the collar elevation. These three points now define the plane of the vein. A similar set of three points will define a second vein, and it is our object to show analytically their intersection if it exists."

Jan 1, 1983

By A. Plugatyr, C. P. Baxter

"Bessemer matte iron content is a critical process parameter that needs to be closely monitored and controlled in order to achieve optimal Ni/Cu smelter returns. Current process control practices during Ni/Cu converting often rely on visual observations and typically involve matte sampling to confirm that target composition was reached. A high-level techno-economic analysis study was carried out to evaluate potential direct benefits of advanced process control during the final stages of Ni/Cu matte converting. The results indicate that the magnitude of direct benefits will largely depend on matte iron control practices already implemented as well as matte iron set point. Preliminary assessment suggests that under the assumptions used in this study, implementation of advanced process control can potentially result in additional revenues ranging from several hundreds of thousands to tens of millions of US dollars per year per converter producing about 200 tonnes of Bessemer matte per day based on Ni, Cu, and Co metal recoveries alone.INTRODUCTION Real-time measurement of molten metal elemental composition, arguably, remains one of the key unresolved issues impeding full automation and real-time optimization of pyrometallurgical operations in different industrial areas, including non-ferrous metals and ferro-alloys. In particular, current process control practices during Ni/Cu matte converting often rely on visual observations and typically involve matte sampling in order to confirm target matte composition. In addition to being time consuming, this approach relies heavily on operator experience and diligence, and, therefore, requires continuous performance and quality control efforts. For instance, the need to improve quality of the Bessemer matte (BM) at the Copper Cliff smelter has prompted an impressive staff engagement and training campaign that was carried out by Vale’s team in the late 2000’s (Zanini, Wong, & Cooke, 2012). This training exercise was executed to address the compounded effect of several operational challenges, namely demand for higher throughputs, changes in the feed concentrate composition, increased feed variability, loss of process knowledge and expertise due to retirement, as well as lack of a comprehensive approach to improving the overall performance of the flowsheet rather than meeting production targets for intermediate products. Although the campaign was very successful and has resulted in significant improvements in the Bessemer matte quality, it has also highlighted the need to move away from “the-art-of-converting” and develop analytical tools that would enable real-time process monitoring."

Jan 1, 2018

By J. Kan

In order to determine the recovery functions in an oil sand circuit it is necessary to have more than a minimal determination the mass flows in the network. This over-determination is essential in order to allow for measurements within the flow matrix "to flex" according to an error function. It is then possible to identify the flows and composition at all points with maximum likelihood. These so-called full mappings are not easily obtained. However, in order to obtain an unequivocal determination of all the unit operations recoveries such a balance is needed. When databases are constructed exclusively with coherently balanced sets of data it is possible to obtain a maximally accurate process model by maximizing the probability of correctly identifying the process causality. Indeed, it is doubtful in cases of normal complexity that any sense can be made of data that is not so balanced. Coherent mass energy balancing is a tool developed by mineral processing scientists and engineers. Its rigorous application to oil sands is the subject of this paper. The additional element associated with hydrocarbon requires special considerations. It is shown that at least one currently available mineral processing tool will solve the full-mapping problem for an oil sand operation. Experimental design constraints are discussed in this paper relating to the development of databases for the development of effective process models.

May 1, 2004

By E. N. Durussel

"The Fox Mine has been producing copper/ zinc ore since 1970 at a rate of approximately one million tons per year, and until 1978all production was derived from longhole open stopes. In June 1978, a trial stope using bighole mining methods was started to eliminate the development of two sublevels between 400 level and surface. The trial proved to be successful, and bighole mining is now an accepted mining method for both stopes and pillars at Fox Mine.When production blasting was started in the first stope, the biggest problem encountered was the production of large amounts of sulphur dioxide gas as a result of secondary sulphide dust explosions. This gas generation resulted in lost production time and caused minor damage to underground installations to the blast level, and to the headframe. Sulphur dioxide generation has been noted in secondary drawpoint blasts and, on rare occasions, in drift rounds.This paper discusses the occurrence of the sulphur blasts and the practices and precautions used to prevent their reoccurrence at Fox Mine.IntroductionThe Fox minesite is located 30 miles southwest of Lynn Lake, Manitoba. With production startup in 1970, Fox Mine is owned and operated by Sherritt Gordon Mines Limited.The Fox orebody occurs as a large lenticular zone of semi-massive sulphides approximately 1,500 feet long and 15 to 100 feet wide running east and west. Dipping 70 degrees to the north, the orebody tends to bottom out at the 3200-foot level and reaches to within 15 feet of surface."

Jan 1, 1981

By Robert B. Parsons

"Several recent cases indicate that the Courts may be leaning toward a more favourable treatment of mine closing and related costs. In this article, we look at two recent cases, Burnco Industries Ltd. and Nomad Sand & Gravel Ltd. The former was heard before the Federal Court - Trial Division and the latter before the Tax Review Board.It appears that in certain situations mining companies may now be able to sustain current deductibility of estimated mine closing costs during the productive years of the mine, rather than waiting until either the date on which mining ceases or the reclamation and similar activities commence. This would be of great benefit to the mining industry, as waiting until the bitter end often means that there are no revenues available against which the expenses may be offset and, hence, no tax relief.IntroductionUnder the Income Tax Act in Canada, taxpayers are not permitted any deductions in respect of an outlay or expense in determining income from a business or property, except to the extent that such expenditures are made or incurred by the taxpayer for the purpose of gaining or producing income. In addition, no deductions are permitted for amounts transferred or credited to a reserve, contingent account or sinking fund except as expressly permitted by the Act.In large measure, these provisions are relevant to the mining industry to the extent that they determine the periods during which expenses may be charged against revenues for income tax purposes. Several recent cases have indicated that the Courts are leaning toward a more favourable treatment of accrued costs in the mining industry than was previously considered to be the case."

Jan 1, 1982

By Hong Zhong, Shuai Wang, Fangxu Li, Guangyi Liu

"The flotation performances and adsorption mechanisms of a-hydroxyoctyl phosphinic acid (HPA) to malachite, cassiterite and wolframite were investigated by micro-flotation tests and X-ray photoelectron spectroscopy (XPS) analyses. The micro-flotation results indicated that compared with styrene phosphonic acid (SPA), diphosphonic acid (DPA), benzohydroxamic acid (BHA) and salicylhydroxamic acid (SHA), HPA exhibited excellent collecting power to the three oxide ores. In addition, HPA showed superior selectivity against hematite, tourmaline, feldspar and quartz. The results of XPS analysis demonstrated that HPA reacts with active species (M) on metal oxide by formation of P-O-M or P-M bonds.INTRODUCTIONIn mineral processing, flotation has been the main process for separation and recovery of valuable minerals from complex ores (Mei, 2013; Zhou, 2014). One of the key requirements in flotation process is to increase selectively the surface hydrophobicity of the targeted minerals by surfactant (known as collector in flotation) adsorption so that these mineral particles can preferably attach air bubbles in a slurry or pulp (Bai, 2004; Hankins, 2004). To anchor a solid surface selectively, special functional group are designed to adjust the interaction between the surfactant and the active sites of solid surfaces (Wu, 2006; Huang, 2014).Organic phosphorous compounds have strong affinity toward metals or metal oxides because they form more stable metal complexes than metal carboxylates (Pazik, 2001; Zheng, 1998). In mineral engineering, phosphorous compounds have been exploited as metal extractants and flotation collectors (Alguacil, 2002; Sun, 2008). Ni (2012) and Zhang (1998) introduced diphosphonic acid (DPA) as an effective collector for flotation of fersmite and niobite. Liu (1999) found styryl phosphonic acid (SPA) was a superior collector for flotation recovery of finely disseminated rutile ores. Gruner and Bilsing (1992) thought SPA was one of the best collectors for flotation recovery of cassiterite which could obtain a high-grade concentrates of more than 40% with high recovery values. Bulatovic (1999) investigated the flotation performances of phosphoric acid ester (PAE) to perovskite, ilmenite and rutile and found that PAE was an impactful collector for selective flotation of titanium minerals from complex ores in the presence of petroleum sulfate. However, a-hydroxyoctyl phosphinic acid (HPA) as a flotation collector for recovery of titanium ores were hardly reported in the previous literatures."

Jan 1, 2016

By L. G. Bergh

The experience developing a supervisory control and information systems in a SX pilot plant is presented. The plant is located at the Process Control Laboratory, Santa Maria University, in Chile. In this work, the problem of controlling this process is discussed and related literature is briefly reviewed. Then, an innovative control scheme organized in three levels, local, hydrodynamic, and metallurgical supervisory controls is presented in an architecture including field controllers, PLC, and PC networks. Operating decisions in the metallurgical supervisory control are taken with incomplete information from on-stream analyzers. The control proposed is based on metal and acid concentration predictions of intermediate and exiting streams through the use of dynamic and static models and flow rates and input concentration measurements. Preliminary results are presented. The main objectives are to develop and test intelligent techniques in a hybrid system, and to study measurement and supervisory control problems. It is expected to produce reliable results that will contribute to improve the efficiency of this emerging and important process.

Jan 1, 2007

By Y. Luo

The rock breakage process in drilling is a main source of noise in roof bolting operations, especially when hard rocks are encountered. Proper control of drilling operation can provide an opportunity to improve energy efficiency of drilling and to reduce noise and heat generated from bit-rock friction. Drilling tests have been conducted in laboratory settings to confirm this noise-reduction strategy. Preliminary results show that the drilling parameters, penetration and rotational rates can be controlled to achieve in a desirable range in drilling medium hard rock. Based on the theoretical and experimental studies, rational drilling control strategy is developed for noise control while maintaining a safe and productive roof bolting operation. Applying this strategy in underground roof bolting operation, the noise exposure of roof bolter operators will be significantly reduced.

Aug 1, 2013

By F. Parada

During copper smelting and converting processes, slag generated is pyrometallurgically cleaned and then disposed, containing around 1 % of this metal. However, important amount of molybdenum initially contained in concentrates also goes to the slag phase. Research on molybdenum recovery from water granulated slags using acid leaching at low temperatures was conducted to find an efficient way for molybdenum extraction with lower magnetite in the slag. However because of the high fayalite content high acid consumption was found. Molybdenum can be recovered from solution using ionic exchange resins, but high silica content interferes with extraction. Some studies addressed to minimize silica extraction as well as alternatives of selective silica precipitation in order to develop a technically feasible process.

Jan 1, 2007

By Solar D. Andrés

Several large open pit mines are facing the challenge to design and plan an underground transition to sustain the long term future of their operations. The desired underground method is Block Cave since its natural high productivity and low operating cost that could compete against the open pit cost to mine the final open pit pushbacks. It has been found at several operations where this transition is taking place that the pit limit at which transition is performed is rather deep. This aims to think that perhaps several transition projects have started late in the life of an operation producing an over stress in the transition project and reducing the flexibility in the design of the overall infrastructure and a substantial lost in the complete project NPV. Traditionally the approach to plan open pit underground transition consists of sequentially deciding the final pit using a Lerchs and Grossman type of optimization to find the overall maximum pit shell and then running block cave simulations to find the best footprint for the underground option. The research summarized in this paper is related to the development of an integer linear programming model that aims to compute simultaneously the maximum NPV of the combined option final limit open pit and block cave underground footprint. The model has been tested using two large block models representing two of the current operations in the process of transiting from open pit to underground operations. Finally, the integrated open pit underground transition model is going to be compared to the traditional sequential approach in order to define which method achieves the best NPV. The paper illustrates both case studies in depth.

Oct 1, 2009

By V. I. Peresypkin, A. Y. Lein, N. S. Bortnikov, Yu. A. Bogdanov

"Abstract - The lipid component in hydrothermal deposits of the Logachev vent field, at 14°45_N of the Mid-Atlantic Ridge (MAR) and Broken Spur vent field, at 29°N of the MAR, was studied. Biochemical, gas chromatographic (GS), and molecular mass methods (GC-MS) research established the mixed nature of the organic matter (OM) including phytoplanktonogenous, chemosynthesized lipids, and lipids of questionable origin. Specific local conditions around the sulfide ores of the black smokers (absence of free oxygen and presence of reduced copper, which prevents OM degradation) facilitate the preservation of biogenic material, including bacteria. The main differences between the lipid compositions of the hydrothermal deposits of these two vent fields relate to the variable nature of hydrothermal circulation systems.At the 14°45_N vent field, high-temperature hydrothermal fields are forming due to the reaction of sea water with upper mantle ultrabasic rocks during serpentinization (a deep hydrothermal circulation system). High pressure and temperature (>400°C), a reducing environment and the presence of various metal oxides are favorable for the abiogenic synthesis of CH4 and oil hydrocarbons (HC). At the Broken Spur vent field, hydrothermal deposits are forming above axial crust magma chambers due to the interaction of sea water and basalts (an axial hydrothermal circulation system). Abiogenic synthesis of HC also occurs in this situation, but to a considerably lesser extent."

Jan 1, 1999

By E. P. Wiechrnann, C. M. Castro, G. A. Vidal

In copper Eta plants the optimal current density setpoint depends on the electrolyte composition and temperature. However, conventional plants operate with large standard deviations. A value of 14% with current densities offsets up to ±50% is typical. For worst, during opencircuit or shortcircuit events this variation can be from -100% to +200%. Naturally, energy consumption and copper quality are compromised. Several devices have been successfully employed to reduce set point deviations. Last developments include; Optibar Segmented Intercell Bars, Outotec Electrodes Arranging Method and NTC Selective Electrodeposition Enhancers. This paper researches and compares these technologies. It is shown that short circuits can be effectively reduced in occurrence and magnitude. Moreover, 95% of the electrodes can be forced to operate within ±10% of the set point. The specific energy consumption is reduced from 2,000 KW per Ton to values close to 1,900 KW per Ton.

Jan 1, 2011

By K. Ghyselbrecht, R. Swennen, Y. W. Chiang, V. Cappuyns, R. M. Santos, T. Van Gerven, B. Meesschaert

Heavy metal contamination from mining and metallurgical activities of aquatic systems poses significant risk to the environment and human populations. The investigation of the distribution and immobilization mechanisms of heavy metals in sediments and soils has recently attained high priority. Different remediation methods can be employed to suppress or eliminate these contaminants. A tailored approach using both commercially available and in-house made adsorbents to rem ediate a heavy metal contamination site due to historical metallurgical activities in north Belgium is studied in this paper.

Jan 1, 2011

By E. Dernedde

A few studies have suggested that the rate of adsorption of hydrogen fluoride on smelter grade alumina is determined by kinetic factors. However, no performance equation for dry scrubbers has appeared in the literature so far. Experimental data from a pilot dry scrubber with co-current flow were compared with results of kinetic models of adsorption, film diffusion and pore diffusion. The pore diffusion model was deemed the most appropriate. It was transformed into a performance equation for steady-state operations of dry scrubbers by the inclusion of the alumina recirculation. Operating results of industrial dry scrubbers with co-current flow were successfully evaluated by means of the performance equation. The average fluoride content of the alumina was also estimated by using the pore diffusion model.

Jan 1, 2011

By T. Y. Chong, J. A. Folinsbee

Since milling began in 1909, the PJV Dome mill has been expanded several times, to the current throughput of 11,500 tonnes per day. PJV recovers free gold using crushing and grinding followed by gravity concentration. The remaining gold in the gravity tails is recovered by cyanide leaching followed by Carbon-In -Pulp processing. Prior to 1993, cyanide tailings were impounded in the tailings pond where cyanide was allowed to degrade naturally. Effluent was discharged seasonally during the summer and early autumn to maintain the water balance. In 1993, an Effluent Treatment Plant (ETP) was designed and constructed for the purpose of removing dissolved metals and suspended solids. In 1997, an INCO SO2/Air cyanide destruction process was added to the ETP. Even though the ETP was successful in meeting the cyanide, metals and total suspended solids (TSS) discharge limits, often the treated effluent failed to pass toxicity tests. Following successful laboratory and plant scale testing, the addition of the chelant EDTA (ethylene diamine-tetra-acetic-acid) was commenced in the 1999 operating season. To date, discharged effluent has passed all toxicity tests. This paper describes the evolution of the ETP from its early conception to the various phases of upgrade needed to meet the MISA discharge limits.

Jan 1, 2005

By N. Fukatsu

The recent development of galvanic cell-type hydrogen sensor for molten copper was outlined. The principle of the sensing mechanism, the fundamental structure of the sensor, and its performance as a process control device are discussed based on experimental work undertaken by the authors. Besides sensors based on usual perovskite-type proton conducting oxide, those using magnesium-doped alpha alumina, which was recently known as a proton conductor, were investigated and the results at the laboratory scale are reported. Considering the excellent sensitivity at high temperature and the stability to the disturbance from the attendant oxygen activity, magnesium-doped alpha alumina was regarded to be a superior material for the sensors used for such purposes.

Jan 1, 2007

By Dwayne D. Tannant

Digital photogrammetry allows rapid, remote measurement of millions of points, thus providing an unprecedented amount of spatial information. Research is being conducted to explore practical applications of digital photogrammetry for monitoring, surveying and mapping in surface mines. The performance, accuracy and operational ease of digital photogrammetry are discussed and practical aspects of conducting digital photogrammetry surveys are reviewed. Case histories from coal, diamond and limestone mines are presented.

May 1, 2006