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Zinc enters into solution on aeration of sphalerite in deionised water. It has been observed that less zinc dissolves in a copper vessel than when the same operation is carried out in a glass vessel of similar shape and size.

Jan 1, 1980

By P. L. Claessens, S. Belisle, C. Bowen

"Use of zinc shot feed is a well-established procedure among North American electro-galvanizers. This form of zinc is easy to handle and relatively inexpensive when compared with zinc oxide. This paper reports results on the kinetics of zinc shot dissolution in traditional pure zinc solutions and in electrolytes used for the plating of nickel/zinc alloys. Despite the cementation of minor amounts of nickel in the latter solution, acceptable dissolution rates of the zinc shot can be achieved through proper adjustment of the solution velocity. Under these conditions, the nickel shell produced by cementation is continuously abraded, exposing the underlying zinc.IntroductionThe use of insoluble, noble metal-containing anodes rather than soluble zinc anodes for the operation of high current density electro-galvanizing lines has gained almost universal acceptance. Two major reasons for this trend are:• improved control of the process by virtue of constant inter-electrode distance; and• increased productivity because the operation of the lines does not require the relatively frequent interruptions for replacement of consumed anodes .The results of the principal anode and cathode reactions are, respectively, depletion of the zinc content of the electrolyte and the increase on its acidity;"

Jan 1, 1991

By M. Seyed Ahmadi

This study investigates the role of nitrogen gas injection in the dissolution rate of Si into liquid Al. A unique revolving liquid metal tank was used, with a capacity of 50 kg of liquid Al. Experiments without gas injection have shown that the dissolution of Si increases as the bath superheat and the tangential velocity of the liquid Al increase. When injecting nitrogen gas at flow rates between 0-5 lit/min in the vicinity of the solid Si, results so far clearly show greater dissolution. In addition, results on the role of the gas flow rate relative to the position of the nozzle are presented and analyzed.

Jan 1, 2011

After the war that was nearing an end In early 1945, regular consulting work for Bralorne, the Bradleys, Pennsalt Chemical Co., and a directorship and occasional consulting for Homestake Mining Co. made it almost certain that in spite of my 61 years I would have enough work to feed my family. But this routine work would not provide enough income to lay up funds for the inevitable future when I could no longer do arduous work. And it would not give me the adventure that had first lured me into mining. Therefore I was greatly relieved as well as pleased when, in the 18 months from April 1945 to November 1946, I was asked to make three of the most adventurous as well as profitable examinations that ever came my way. Pati[n]o Mines, Bolivia The first of the exciting jobs was an examination of the Pati[n]o tin mines in Bolivia. After I had unsuccessfully tried to induce Anaconda to purchase these mines In 1915, the World War I crisis that had forced the half-Indian accountant to try to sell the mines had come to an end. The European market for tin improved dramatically, and "Don Simon" was able to borrow money for expenses while the concentrates were still In Bolivia. He took advantage of the favorable conditions by buying adjacent properties and increasing development work until his Bolivian tin mines were the greatest in the world. And his daughter had marled the French Count de Boisrouvain and was cutting a swath In high International society. Pati[n]o wanted to get rid of the drudgery of running a complicated mining Industry in a remote area In Bolivia when the fleshpots of Paris were much more seductive. An added incentive was the fact that his miners had become unruly and had even threatened his 11fe.

Jan 1, 1976

By H. S. Bell

It seems unnecessary to dwell upon the advantages of the modern pipe still as compared with the older type of distillation equipment used by oil refiners. The relatively low installation cost, coupled with remark-able operating efficiencies of pipe stills, precludes the consideration of other types except in rare instances where some peculiarity of product or plant may have an influence. The question of the actual heat required to distil petroleum is quite involved. We have extensive data on the latent heats of the various hydrocarbons under different conditions of pressure. We also have information regarding the specific heats of various oils and the effect of temperature thereon. Because of the complexity of petroleum and of each fraction, it seems impossible to analyze theoretically the partisl-pressure effect of the great number of hydrocarbons upon one another during distillation. If a distillation curve and percentage analysis of any crude or product are available, it is possible to construct a curve with ordinates representing per cent. distilled and B. t. u. per pound or per gallon, or other desired unit. To do so the crude is split into fractions, of 5 or 10 per cent. The boiling point and gravity of each fraction being determined, it is possible to evaluate the heat required. As each fraction is removed, the residue must be raised to a higher temperature and latent heat supplied for the successive fraction. As the calculations progress, the latent heats decrease while the specific heats increase. Such a curve is illustrated by Fig. 1 for a typical 39.9° Be. North Texas crude. The chart is illustrative of batch distillation. Theoretically, if the oil were heated by a single flash in a pipe still, the partial-pressure effect of the light products would result in the removal of the same amount of vapors at a lower temperature. Practically, we find that because of the necessarily extensive fractionating equipment required when separating many products all in vapor phase, the oil has to enter the separator at temperatures corresponding to or even above those required in the batch still. Furthermore, in single-flash distillation the vapors evolved in the heater must be superheated to the outlet temperature. Very little is

Jan 1, 1928

By Taghi Sherizadeh, Kutay E. Karadeniz, Dogukan Guner, Samuel Nowak

Despite numerous empirical, numerical, and hybrid studies conducted on the subject of coal rib failure, mine fatalities related to rib failures continue to occur. To date, a standard methodology for the design of coal rib supports which can accommodate the wide range of unique conditions found in coal mines in the United States has not been developed, forcing mine operators to rely on the trial-and-error process or industrial legacy practices for the design of coal rib support patterns. In this study, to better understand the support systems' effectiveness, various rib bolting scenarios were investigated. A coal mass constitutive model is implemented to a Distinct Element Method (DEM) code, and rib factor-of-safety (RibFOS) analyses were performed by applying strength-reduction for the coal matrix and explicitly modeled face cleats. Ribs with various overburden depths and mining heights composed of solid Banded-Bright coal (BBC) were considered in this study. Different scenarios such as rib bolt length and the number of bolts were studied to quantify the effect of primary rib support density on rib stability. As a result of the unsupported coal rib analyses, a decaying exponential relationship is proposed between the mining height-overburden depth and the RibFOS. The developed coal rib models clearly show the coal-rib bolt interaction and illustrate how the addition of rib bolts restricts the movement of the coal rib. The results reveal that the strength reduction method in DEM code with the coal-mass model can aid in the development of practical primary support charts, which can help in the rib support design process. In addition, an unsupported RibFOS cutoff

By MAURICE SUNKPAL, Taghi Sherizadeh, Kutay E. Karadeniz, Dogukan Guner, Samuel Nowak

Despite numerous empirical, numerical, and hybrid studies conducted on the subject of coal rib failure, mine fatalities related to rib failures continue to occur at around 1.5 per year between 2009 and 2021. To date, a standard methodology for the design of coal rib supports that can accommodate the wide range of unique conditions found in coal mines in the USA has not been developed, forcing mine operators to rely on the trial-and-error process or industrial legacy practices for the design of coal rib support patterns. In this study, to better understand the support systems’ effectiveness, various rib bolting scenarios were investigated. A coal mass constitutive model is implemented to a distinct element method (DEM) code, and rib factor-of-safety (RibFOS) analyses were performed by applying strength-reduction for the coal matrix and explicitly modeled face cleats. Ribs with various overburden depths and mining heights composed of solid Banded-Bright coal (BBC) were considered in this study. Different scenarios such as rib bolt length and the number of bolts were studied to quantify the effect of primary rib support density on rib stability. As a result of the unsupported coal rib analyses, a decaying exponential relationship is proposed between the mining height-overburden depth and the RibFOS. The developed coal rib models clearly show the coal-rib bolt interaction and illustrate how the addition of rib bolts restricts the movement of the coal rib. The results reveal that the strength reduction method in DEM code with the coal-mass model can aid in the development of practical primary support charts, which can help in the rib support design process. In addition, an unsupported RibFOS cutoff is proposed, beyond which the addition of primary support cannot stabilize the failed rib structure.

Aug 5, 2023

By Zhiguo Chang, QINGXIANG CAI, Ebelia Manda, IZHAR MITHAL JISKANI, XIANG LU, Wei Zhou, Saleem Raza Chalgri

The concept of mine safety is highlighted in the literature of sustainable mining but not extensively discussed. This study analyzes various aspects of underground and surface mine safety and emphasizes its importance in the context of sustainable mining. More specifically, this research attempts to find the relationship between mine hazards and demographic characteristics, examine and compare the perceptual difference among miners, and determine the impact of mine hazards on workplace safety and safety climate. Descriptive analysis, chi-square test, independent samples t test, and linear regression modeling were conducted to achieve study objectives. Results confirmed that mine hazards were significantly associated with age and experience. Miners perceived lower levels of management safety practices, followed by supervisor safety, coworker safety, and job safety. The analysis showed that underground miners reported lower safety scores than surface miners. There was a statistically significant difference between miners’ perception of safety climate (p < 0.05). The results showed that the higher prevalence of mine hazards predicts poor workplace safety and a low safety climate. The regression models revealed that mine hazards have a significant effect on workplace safety (p < 0.05) and safety climate (p < 0.05). In conclusion, the distinctive model of mine safety presented here contributes to the monitoring and design of comprehensive safety interventions and helps to better understand how certain factors interact on multiple levels to influence the overall safety of the industry. In this study, some suggestions are put forward to provide directions to develop a sustainable mine safety system.

Mar 27, 2020

By J Chan, T Baumgartl, A Plante, C Peltre, P D. Erskine

Mine soils are often organic matter and carbon poor due to disturbance, topsoil stockpiling and mixing with spoil. They present an opportunity to observe the accumulation of soil carbon arising from rehabilitation or ‘green carbon’ through organic matter inputs and may be considered for carbon credits. Soil carbon is known to improve multiple soil characteristics and is viewed as an indicator of soil health.When attempting to estimate soil carbon levels in the Australian coal mining regions, both coal and black carbon (BC) need to be quantified. Coalmine soils contain coal particles that are difficult to distinguish from organic matter using standard carbon analyses. BC, a material arising from the incomplete combustion of organic matter and fossil fuels, displays some similar characteristics to coal and is ubiquitous in Australian soils due to bushfires. The presence of coal and BC complicate the determination of green carbon levels in mine soils.A method to quantify coal and BC in mine soils from the Bowen Basin using thermal analysis and multivariate curve resolution is presented. By determining BC and coal contributions it is then possible to calculate green carbon levels in rehabilitated mine soils. Calculated green carbon levels are compared with bulk density as soil quality indicators.CITATION:Chan, J, Baumgartl, T, Erskine, P D, Peltre, C and Plante, A, 2014. Distinguishing carbon fractions in coalmine rehabilitated soils, in Proceedings Life-of-Mine 2014 , pp 491–498 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By R N. Lamb, A N. Buckley

Experiments have been carried out to establish whether time-of-flight secondary ion mass spectrometry (ToF-SIMS) is able to differentiate monolayer and multilayer coverage of thiol collectors on sulfide minerals. The systems investigated were those for which x-ray photoelectron spectroscopy is able to provide an independent determination of the extent of coverage, and included diethyldithiophosphate (DTP) and 2-mercaptobenzothiazole (MBT) on chalcocite, DTP on Ag2+MS prepared by sulfidising metallic silver, and isobutyl xanthate (BX) and MBT on galena. For monolayer adsorption of MBT on chalcocite, peaks from MBTû but not Cu(MBT)û ions were evident. For multilayer coverage, Cu(MBT)2û ions were clearly present, notwithstanding the fact that other data had identified the principal multilayer species as Cu(MBT). For adsorbed DTP on copper and silver sulfides, DTPû and metal(DTP)Hû peaks were observed for monolayer and multilayer coverage. Although the multilayer species was expected to be predominantly metal(DTP), metal(DTP)2û ions were evident for multilayer (but not monolayer) coverage. For the PbS/BX system, intact Pb(BX)2 or Pb(OH)BX ions were not detected for multilayer coverage, although Pb-containing ions heavier than PbBX were. Indeed, for all the systems studied, ToF-SIMS was able to differentiate monolayer from multilayer coverage. In general, however, the SIMS evidence alone might not be sufficiently definitive to effect the differentiation. In the case of collector adsorption on copper and silver sulfides, if the multilayer species detected had been the metal monothiolate only, and had not involved the formation of some metal dithiolate, then ToF-SIMS might not have been able to provide an unequivocal differentiation of the two coverage conditions.

Jan 1, 2005

By Albert L. Brautigam, Michael R. Yenchek, Jeffrey Shawn Peterson, James C. Cawley

The National Institute for Occupational Safety and Health investigated how the starting of induction motors may cause nuisance tripping of short-circuit protection on coal mine power systems. This research had a dual purpose: 1) to identify how motor-start waveforms differ from those for short circuits and 2) to devise a method to provide short-circuit protection without intentional time delays to account for motor starts. This technology will help ensure that surface temperatures of energized electrical apparatus will not exceed gas or dust ignition thresholds when short circuits occur.

By T Bednarz

The present work proposes a distributed collaborative immersive virtual reality framework for prospective applications in the mining industry. A human-centered approach is described, with people being placed in the central position and surrounded by tasks that are to be carried out. Those tasks can be then achieved through synchronous or asynchronous communication, interactions using properly constructed user interfaces, virtual and/or augmented realities and computer vision. Several examples of such arrangements are presented. One of the applications facilitates an e-learning experience by providing a very familiar object – a book – as a target for users to interact with. Importantly, this system has the potential to provide an ‘enhanced’ teaching medium, as humans tend to remember events/situations better when they experience those events in person, when the immersive factor is involved. The immersive virtual reality environment enables a user to interact physically with various 3D objects and experience behaviours, which in turn reinforces the idea that doing leads to learning. This prototype system can be implemented as an efficient and cost effective e-learning and training platform for different engineering domains. At another level, the same technology can be used in the tele-operation of mining equipment for the future mine.

Nov 22, 2011

By A. Desbiens, R. del Villar

"This two-part paper summarizes the design and implementation of a distributed PIbased control strategy installed at the B grinding circuit, at the Kidd Creek Division of Falconbridge Ltd. Part I details the design of the control strategy using a grinding circuit dynamic simulator (DYNAFRAG). The first step consisted of sampling campaigns and data processing to calibrate DYNAFRAG. Then, several control alternatives were designed and tested with the simulator. The main feature of these strategies is their ability to regulate or keep within an upper and lower limit five output variables (circulating load, rod mill density, cyclone feed and overflow densities and pump box level) with only three manipulated variables (rod mill water, pump box water and rod mill tonnage). By simulation on DYNAFRAG, it was possible to discriminate among several control structures. The preferred control strategy uses a saturation algorithm, which allows the adequate regulation of two measured variables with only one actuator. Controllers located in interacting loops are appropriately tuned, taking into account the existing process coupling. Part II will present the implementation of the selected control strategy.IntroductionSteady state simulators are used to predict the stationary state of a given process under specific operating conditions. Tradi - tionally, steady state simulation has been applied for process flowsheet design, for evaluating process modification benefits or for determining key operating parameters in process operation optimization. Dynamic simulators add a new dimension to process simulation since they allow the prediction of the process transient behaviour, resulting from the application of a different set of operating conditions and/or from natural disturbances or equipment failure. Dynamic simulators can also be used for the training of new operators or for the design of control strategies."

Jan 1, 1997

By A. Desbiens, A. Pomerleau

During the summer of 1994, a new PID-based control strategy was installed on line B of the grinding circuit at the Kidd Creek Division of Falconbridge Ltd. Part I of this paper described the methodology used to select the appropriate control strategy using a phenomenological dynamic simulator. Part II presents the implementation of the control strategy. Prior to the controller installation, it was necessary to solve various problems related to the process, such as a cyclic behaviour of the rod mill feed tonnage, a problem related to the mill water source and the calibration of the flowmeters. Once these problems were solved, the control strategy was accomplished in two steps. Step 1 corresponds to the installation of control loops to regulate the pump box level and the cyclone overflow density. Step 2 describes the implementation of a loop to control the cyclone feed density. According to Part I, a loop to control the circulating load is also part of the original design. However, reasons are given to explain the rejection of this loop. For both steps, technical procedures such as filtering, process identification and controller tuning are detailed. Finally, the operator’s interface is briefly described.

Jan 1, 1997

By B. J. Huls

The commissioning of a Distributed Digital Control. System for the grinding circuit at Cuajone, was completed by mid August, 1985. Development of a successful strategy, excellent operator acceptability and the visual aspects offered by the display of the central console, improved mill throughput significantly. The inherent features of a digital system enhanced the flexibility in grinding control and allowed the mills and classifiers to be operated at maximum capacity. This paper discusses in detail the strategy development, the production restrictions encountered, and evaluates the overall performance of the digital control system. 1.0 Introduction In November 1976, the Cuajone Concentrator, located on the western slope of the Andes in Southern Peru, was commissioned to treat a nominal 41,000 TPD of ore. A systematic elimination of production restrictions has resulted in a continual increase of concentrator throughput to 48,700 TPD before the grinding control was in- stalled.

Jan 1, 1986

By D. R. Pyke, R. S. Middleton

"Three main types of base metal sulphide mineralization are present in the Timmins area:(1) -Massive and stringer-type copper-zinc deposits occurring mainly in pyroclastic rocks, as typified by the mines of Kam-Kotia, Jameland and Canadian Jamieson, or within or close to possible breccia pipes as shown by the Genex and Kidd Creek mines. With the exception of the Kidd Creek mine, all of these orebodies occur northwest of Timmins (Kamiskotia area) and appear to lie within or close to a major center of volcanic activity characterized by a thick accumulation of felsic pyroclastic rocks and subordinate epizonal intrusions. The margins of the rhyolitic pile are interfingered with mafic volcanics; overlying sedi-ments mark the termination of a vol-canic cycle. The copper-zinc deposits in the Kamiskotia area are confined to a particular stratigraphic unit. Ore-bearing solutions were probably derived from the intrusive complex of the volcanic pile.(2) -Porphyry copper deposit of the Mcintyre mine. The deposit occurs in a quarz porphyry intrusion related to the volcanism in the area (Hurst, 1936). Mineralization was probably introduced at the time of intrusion, and subsequently redistributed within the porphyry during deformation. (3) -Massive and disseminated nickel mineralization, associated with serpentinized alpine-type ultramafic intrusions, as shown by the Alexo, McWatters, Hart, Inco and Texmont deposits. The nickel mineralization occurs at or near contacts of the serpentinites with felsic or mafic volcanics, or sulphide-bearing iron formations. The nickel deposits south of Timmins are confined to a particular stratigraphic unit along the margins of domical-shaped structures which appear to outline former volcanic centers. Sulphurization as pro-posed by Naldrett (1966) appears to be a workable hypothesis for the formation of some of the deposits."

Jan 1, 1971

By Thomas Clark

This report presents a review of the distribution and exploration potential of platinum-group elements (PGE) in Québec; it is based on published and unpublished analytical data. This qualitative evaluation of the PGE potential, whether in PGE-dominant deposits or in Ni-Cu-dominant deposits with co-product PGE, is based on interelement ratios such as Ni/Pd, Cu/Ir, Cu/Pt, and Cu/Pd. Good PGE targets, i.e., deposits associated with magmas fertile in PGE, are identified. Less favorable PGE targets, i.e., deposits associated with PGE-depleted magmas, are also mentioned. The importance of exploring for deposits similar to those at lac des Îles and East Bull Lake (Ontario) is emphasized.

May 1, 2001

By K. Yamaguchi

"This Precious metals content copper scrap is treated with a copper smelting process, and copper and precious metals are recovered. The precious metal lost in the slag is increasing with increasing of treated scrap amount. To determine the portion of the precious metals chemically dissolved and that associated with the mechanically trapped matte in the slag will be a key factor to improve the recovery of those metals. The distribution of precious metals between copper matte and FeOx-SiO2 slag phases is determined at 1300 oC and a fixed partial pressure of SO2 of 0.1 atm for the matte grades from 40 to 70 mass% of copper. The distribution ratios show a tendency to increase when the grade of matte is increased. In addition, the solubility of platinum and rhodium in the FeOx-SiO2-CaO slag under the air and the solubility of platinum in the FeOx-SiO2 slag equilibrated with a pure platinum or the Pt-Cu alloy were determined at 1300oC in the range of oxygen partial pressure from 10-9 to 10-7. The solubility of platinum and rhodium in the slag tends to increase with increasing content of copper in the slag and oxygen partial pressure. INTRODUCTIONThe stringency of the supply and demand of platinum group metal (PGM) intensifies by localization for resources and increase of the demand for PGM, furthermore, smelting and the recycling of PGM in the nonferrous smelting process take an important role. Scrap containing a precious metal for the purpose of collection of PGM is treated by copper smelting recently. With increase of the treatment amounts, loss of PGM in slags is the serious problem.In considering of PGM loss in slags, knowledge of the distribution behavior for PGM between slag and matte phases or slag and copper phases and the PGM solubility in slags is important. The distribution ratios of silver and gold between the FeOx-SiO2 slag and the Fe-Cu matte were reported by Roghani (Roghani et al., 2000), Shinha (Shinha et al., 1985) and Takeda (Takeda et al., 1993) However, there is no data for the PGM distribution ratio. On the other hand, the PGM solubility in slags was reported by Sano (Sano et al., 1997) However, there is very few report for the solubility of PGM in the nonferrous smelting slags."

Jan 1, 2012

By Supachai Surapunt

The distribution behavior of V A minor elements (As, Sb and Bi) in the smelting stage of the Mitsubishi process were evaluated thermodynamically based on thermodynamic data and operating data. The fractional distributions between the gas, slag and matte phases considered as the degree of vapor saturation of 1.0 are as follows: 53.8, 27.2 and 19% for As, 23.6, 56.6 and 19.8% for Sb, and 91.3, 1.1 and 7.6% for Bi, respectively. Arsenic is mostly distributed to the gas and slag phases. It is effectively eliminated by volatilizing and slagging. Antimony is mainly in the slag phase, which is suitably removed by slagging. Bismuth is easily vaporized to gas phase. The degree of vapor saturation has a large effeet on the distribution behaviors of the three elements between the three phases. The amount of a minor element in the charge has an effect on the distribution of As but no effect on the distributions of Sb and Bi. Increasing matte grade and temperature results in the change of distributions for As and Sb, significantly. The change in the distribution ratio between slag and matte phases also considerably affects the distributions of As and Sb. The distribution behavior of Bi is not significantly changed by the change in matte grade, temperature and distribution ratio.

Jan 1, 2003

By Supachai Surapunl

The distribution behavior of VA minor elements (As, Sb and Bi) in the smelting stage of the Mitsubishi process were evaluated thermodynamically based on thermodynamic data and operating data. The fractional distributions between the gas, slag and matte phases considered as the degree of vapor saturation of l.0 are as follows: 53.8, 27.2 and 19% for As, 23.6, 56.6 and 19.8% for Sb, and 91.3, l.1 and 7.6% for Bi, respectively. Arsenic is mostly distributed to the gas and slag phases. It is effectively eliminated by volatilizing and slagging. Antimony is mainly in the slag phase, which is suitably removed by slagging. Bismuth is easily vaporized to gas phase. The degree of vapor saturation has a large effect on the distribution behaviors of the three elements between the three phases. The amount of a minor element in the charge has an effect on the distribution of As but no effect on the distributions of Sb and Bi. Increasing matte grade and temperature results in the change of distributions for As and Sb, significantly. The change in the distribution ratio between slag and matte phases also considerably affects the distributions of As and Sb. The distribution behavior of Bi is not significantly changed by the change in matte grade, temperature and distribution ratio.

Jan 1, 2003