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By D. M. Maijer, S. M. Mohseni, A. B. Phillion

The microstructure evolution kinetics of aluminum alloy B206 during artificial aging has been investigated using non-isothermal calorimetry. A combination of differential-scanning calorimetry (DSC) and tensile tests have been utilized to develop an Avrami model to predict the precipitation kinetics as a function of the thermal processing parameters. The Avrami coefficients, found based on a Kissinger analysis, compare well against those reported in the literature for aluminum-copper alloys. The rapid precipitation kinetics predicted by the Avrami model at temperatures higher than 200°C were assessed through a qualitative comparison against hardness measurement results. In contrast to the continuous hardening observed at 150°C, the material softens with continuing heat treatment at 250°C resulting in an overaged state. This can be attributed to the rapid precipitation kinetics at this temperature, leading to the termination of the precipitation-hardening effects at early stages of artificial aging.

Jan 1, 2015

By D. A. Beattie

Talc is a commonly encountered gangue mineral in metal sulfide flotation. Talc is naturally hydrophobic, resulting in high recoveries if polymeric depressants are not used to specifically reject this MgO containing mineral. We have studied the adsorption of a selection of polymers onto talc using a variety of techniques. Adsorption isotherms have been determined using ex situ depletion techniques and in situ ATR-FTIR spectroscopy has been used to determine adsorption kinetics. Adsorbed layer thicknesses have been determined for the polymers on cleaved talc surfaces using the AFM. The effect of the adsorbed polymer layer on the properties of the talc surface has been quantified through contact angle measurements and single mineral flotation tests. Distinct correlations are observed between the adsorbed layer properties and the flotation performance of the polymers. These observations are discussed with reference to the bubble-particle attachment process and the molecular structure of the polymers.

Jan 1, 2006

By V. Bonilla-Sierra, M. Elmouttie, L. Scholtès, F. V. Donzé

In the presence of joint sets sub-parallel to a slope face, the stability of the rock mass is controlled by the shear strength of the joints. On one hand, if the joints are persistent their shear strength can be assessed according to Mohr-Coulomb criterion, assuming appropriate values for the cohesion and the friction angle on the joint surface. On the other hand, if the joints are non-persistent with their continuity being interrupted by the presence of rock bridges, their shear strength will increase considerably. In this latter case, the contribution of the rock bridges to the shear strength of the joint has to be accounted for in order to better assess the stability of the rock mass. A numerical analysis of the progressive failure of a rock slope involving a non-persistent joint has been set up based upon simulations performed using a Discrete Element Method (DEM) algorithm specifically enhanced for the modeling of jointed rock masses. Pre-existing discontinuities are explicitly accounted for in the model by using a modified contact logic that ensures an explicit and constitutive mechanical behavior of the joint planes. In addition, rock bridges can be spatially distributed along these joint planes following a prescribed probabilistic technique. Jennings’ formulation (Jennings, 1970) is considered as one of the first rock slope analysis that evaluates the shear resistance to sliding as a weighted combination of the shear resistance of the intact rock and the joint planes. The validity of this formulation is discussed in the present study. Contrary to the Jennings’ formulation, we show that tensile failure is an important mechanism, particularly as the dip angle of the sliding plane increases.

Jan 1, 2015

By Kan Xing

This paper introduces common detrimental consequences to the environment from mining in the Beijing West Mining Area. For example, ongoing mining operations can cause the following environmental deterioration: rock burst, roof rises, roof falls and inrush (Pit dash for ward water). Post-closure, after minerals resources are exhausted, the following environmental issues may remain: landslides (collapse, and mud-rock flow), dropping or exhausted water tables, water pollution, desertification and soil erosion, water accumulation, Slay endanger, ground subsidence, and causal factors in seismic activity. This paper analyzes this wide range of environmental consequences of mining, and offers a theoretical foundation to underpin a corresponding management scheme.

Aug 1, 2013

By J. M. Ortiz, J. P. Bertini

"In mineral resource and ore reserve estimation, several sources of information are generally available, such as diamond drillholes, reversed-circulation drillholes, and blastholes, and originate from one or more sampling campaigns and are analyzed by one or more laboratories. In such a situation, the grade measurements may not have the same precision and one should distinguish between hard and imprecise data.This work aims at studying the impact of data imprecision in resource/reserve evaluation through two case studies on simulated deposits: a porphyry copper deposit conditioned to real exploration and production data, and a gold deposit simulated without any conditioning data. Several geostatistical techniques are used to estimate the grades of selective mining units from exploration samples, including kriging, cokriging, lognormal and indicator kriging. Two types of imprecision are examined— measurements with multiplicative errors and measurements defined as intervals. The results are compared to the simulated grades of the selective mining units from a statistical and economic viewpoint.The study concludes that imprecise measurements should never be discarded because they help to improve the estimates, and that simple methods such as kriging are as efficient as more sophisticated ones for resource/reserve assessment. Finally, a few indications on how to diagnose and model the data imprecision are given."

Jan 1, 2005

By David Stone

The Beal Mountain Mine near Anaconda, MT is an interesting case history of a mine that has continued operations despite several large pit wall failures over a period of about 10 years. The largest event involved some 3.9 million tons of rock that has moved steadily at a rate of about 0.05 ft/day since 1992. This paper documents the geotechnical instrumentation and monitoring programs implemented at Beal to provide the company with a comfortable baseline that supported ongoing operations. The success and failure of a variety of stabilization measures will be discussed, along with typical instrumentation responses for several significant events. The success of Beal Mountain serves as a good model for mines faced with serious geotechnical challenges.

May 1, 2001

By J. Bardinas

"The use of autogenous mills has become widespread, owing to their capacity and favorable capital and operating costs. Optimal operation of these systems is critical, given their high energy consumption and effect on downstream processing. A considerable effort has been spent over the years in the development of advanced control systems to achieve a better performance in this regard. However, despite significant advances, the problem still remains challenging, owing to the nonlinear behaviour of the system with respect to the mill variables, and, the unmeasured ore variability come from the mine.The mill load, in particular, can be seen as a state variable of the mill, which could be important for; modelling and control, and, important insights into the mill behaviour. In this investigation, time series cluster analysis was performed using online mill load measurements in order to identify the different control states of the mill. More specifically, this time series was divided into short non-overlapping segments. A distance matrix was set up for each segment and the information was captured by means of textural features, similar to that used in multivariate image analysis. These wavelet and grey level cooccurrence matrix features could subsequently be used to rapidly identify the normal operating conditions from the feed disturbances in the mill.In principle, the methods and models presented here, once suitably validated and calibrated, could be used in online process monitoring of autogenous mills. They also could serve as a foundation for developing more advanced process control models."

Jan 1, 2016

By Ahmad Ghahreman, Denver Cowan, Yeonuk Choi

"Previous testwork by the authors has indicated that both granular coconut shell based activated carbon and a new microporous carbonaceous bead, Lewatit® AF 5, are highly effective in improving the oxidation kinetics and decreasing the elemental sulphur yield when assisting the atmospheric oxidation of pyrite. While the two carbon catalysts show similar results and improvements to the pyrite oxidation, there are differences between them. For example, the activated carbon assisted oxidation showed faster kinetics than the AF 5 assisted oxidation, while elemental sulphur seemed to remain adhered to the surface of the AF 5 after oxidation when much of the elemental sulphur formed during the activated carbon assisted tests was found in the oxidation residue. The objective of this paper is to investigate the differences between the two catalysts through the use of scanning electron microscopy, photography, Raman spectroscopy, surface chemistry analysis, and Brunauer-Emmett-Teller (BET) surface area analysis. With this investigation the authors should be able to achieve a better understanding of the surface chemistry of the two carbon catalysts (i.e. functional groups, charges, acidity etc.) and help explain the strengths and/or the weaknesses of the catalysts when applied to the atmospheric oxidation of pyrite.INTRODUCTION Previous research conducted by the authors, indicated that both a granular coconut shell based activated carbon (activated carbon) and a microporous carbonaceous bead, Lewatit® AF 5 (AF 5), acting as a catalyst enhanced atmospheric pyrite oxidation in ferric sulphate media by approximately 40% when compared to unassisted oxidation and that elemental sulphur yields were increased from 23% to approximately 69 and 63% when assisted by AF 5 and activated carbon respectively (Cowan, Jahromi, & Ghahreman, 2017). The study indicated that although total pyrite oxidation assisted by the two catalysts was similar, differences were noticed in the impact that the two catalysts had on the outcome of the oxidation. Kinetic curves in the Cowan et al. study indicated that atmospheric oxidation of pyrite seemed to reach completion after 48 hours of oxidation when assisted by activated carbon. A similar trend was noticed in the kinetic curves for oxidation when assisted by AF 5, however the oxidation curve did not reach completion until approximately 96 hours (Cowan et al., 2017). This observation indicated that the kinetics of pyrite oxidation are enhanced by both catalysts, oxidation kinetics are much faster when assisted by activated carbon rather than AF 5."

Jan 1, 2017

By G. D. Garland

"IntroductionALTHOUGH the presence of rock salt in the Carboniferous basin of northern Nova Scotia has been known for at least one hundred and twenty years, and salt has been mined at Malagash continuously since 1919, certain characteristics of the deposits make exploration by drilling or surface examination difficult. The surface rocks of the basin are, in general, of Pennsylvanian age, while the salt occurs in the Mississippian Windsor group. The latter rocks are brought to the surface only along anticlinal folds, or as irregular fault blocks. Because of the limited areal extent of these Windsor exposures, and their complicated internal structure, geophysical surveys, especially gravimetric, can be of considerable aid in outlining the more favourable areas.The present paper describes the results of recent investigations by the Dominion Observatory, in cooperation with the Nova Scotia Department of Mines. It includes a regional study of that section of the Cumberland basin lying between Springhill and Malagash ( Figure 1), and a much more detailed survey of the immediate vicinity of the Malagash deposit itself. This deposit had been studied by Miller (6, 7) with the torsion balance nearly twenty years before, and a direct comparison between the results given by the two types of instruments is therefore possible."

Jan 1, 1955

By S. Ng, Peter Stapleton, Paul Mankowski, J. Spence, R. Siy

"Syncrude has developed a low energy extraction process for the recovery of bitumen from oil sand. This new process operates at a temperature of 25 °C, resulting in substantially lower energy costs and lower capital costs, especially for the thermal energy generation equipment. The process will be used in Syncrude’s Aurora Mine, which is scheduled for startup in mid 2000. The flowsheet for Low Energy Extraction includes hydraulic transport of oil sand slurry, and bitumen separation using collector and frother chemicals and air as process aids. A number of flow sheet innovations and optimizations have been included, resulting in the next generation of extraction technology. Experimental pilot plant results, engineering progress to date and areas of ongoing work will be discussed. SUMMARYThe Low Energy Extraction Process has been successfully developed for commercial implementation at Aurora. The 1996 100 tonne hour Field Pilot demonstrated that the bitumen recovery target could be met with an 11.1% grade oil sand. However, pilot plant bitumen recoveries for a lower grade oil sand were not acceptable. The subsequent flowsheet optimization study led to a new flowsheet for Low Energy Extraction, which includes a primary separation vessel, a flotation circuit for PSV middlings, and the use of middlings displacement in the PSV cone bottom with flotation underflow. A test program conducted in 1997 showed that the new flowsheet could significantly improve the bitumen recoveries for lower grade oil sands. Engineering work on process scale-up led to selection of a 30 meter diameter PSV, with a tangential feedwell. The successful development and commercialization of Low Energy Extraction for the Aurora Mine Project is a major enabling step in the Syncrude 21 program. The low energy requirements of this process allow Syncrude to develop the Aurora leases more cost effectively. The use of this process results in major capital cost savings, predominantly in the thermal energy infrastructure and also provides long term operating cost advantages for Syncrude."

Jan 1, 1999

By D. J. MacKinnon

"The Canadian Copper Company, formed in 1885, began mining the nickel-copper ores of Sudbury in 1887 and producing nickel-copper matte from its smelter in 1888(1). Although it was quickly appreciated that the separation of nickel and copper (i.e. refining) was critical to the production of a marketable nickel product, refined nickel was not produced in Canada until about 1918. From the beginning of the industry, there was considerable political agitation to refine nickel in the Province of Ontario(2). The companies, however, claimed that the existing processes, viz. the sodium sulphide ""tops and bottoms"" process operated by the Orford Copper Company of New Jersey, U.S.A.(1,3,4) and the carbonyl process(5,6) developed by the Mond Company at Clydach, Wales, were too costly to operate in Canada. Nickel was first refined in Ontario about 1918 when the International Nickel Company opened a nickel refinery at Port Colborne, Ontario(6). Initially, however, the refinery at Port Colborne employed the Orford sodium sulphide process, and the first electrorefined nickel in Canada was produced in 1920 by the British America Nickel Corporation whose mine and smelter were located in Sudbury, Ontario, but whose electrorefinery was located at Deschenes, Quebec, near Ottawa, Ontario. The purpose of this article is to outline the early history of nickel electrorefining and to trace the significant developments which led to the first successful commercial electrolytic nickel refinery in Canada. The development of an electrolytic process for refining nickel is due largely to the efforts of four individuals, viz. Carl Hoepfner, Hans A. Frasch, D.H. Browne and ultimately N.V. Hybinette, and the contribution of each is discussed separately below."

Jan 1, 1999

In several European countries, including Russia, it has become economically attractive to utilize peat as a fuel for power generation, the production of metallurgical coke, the production of fuel briquettes for the domestic market and low-Btu gas. Although the economic base and availability of energy supplies in Europe is much different than it is in Canada, regional economics here may warrant the development of peat as an alternative source of energy. Canadian peatlands cover several thousands of square miles and have historically been considered as waste land. Now, with the increasing costs of other energy sources, it is apparent that fuel peat should be re-evaluated as a potential energy resource. A nation-wide inventory of peat deposits has been prepared and reserves evaluated for some of these areas where field surveys have been carried out. The paper describes alternative mining methods developed to meet some of the various conditions encountered on virgin peatland . These mining techniques are generally based on current peat technology exercised in other parts of the world and would be applicable in some of the peat regions of Canada. Cost estimates have been prepared for peat production in regions of Canada, and the socio-economic aspects of a large-scale fuel peat operation are discussed. Several potential utilization schemes have been described, with particular emphasis on electric power generation. The paper makes recommendations for steps to be taken in the development of a fuel peat industry in Canada.

Jan 1, 1978

By D. Nower

"The supply of copper is expected to be at a large deficit in 2012. To recover from these deficits mining companies are required to maximize production and there is no better way to accomplish this than to optimize the use of their mobile mining equipment fleets. To optimize these fleets, each equipment type has to be monitored in its own unique way. Automation would not only improve production, but also minimize the safety risks and eliminate planning errors. The automated vibration monitoring of multiple systems on the shovel can determine the machine’s condition at all times. This reduces unplanned downtime and keeps critical shovels in production. This paper will discuss the details of how shovels can be successfully monitored, continuously. INTRODUCTIONP&H Mining, part of Joy Global, is the world’s largest manufacturer of above-ground mining equipment. Its electric rope shovels, such as Figure 1, with capacities up to 115 tons (104.3 metric tons), are used for high production loading in surface mines; its draglines, such as Figure 2, have bucket capacities to 160 cubic yards (122 cubic meters). P&H also produces blasthole drills, mobile mining crushers and other essential mining equipment. Headquartered in Milwaukee, WI, the company does business on every continent, except Antarctica. ECONOMIC FACTORSDue to the global demands for metals and power, mines are required to operate at full capacity. Mine operations cannot afford any critical assets to shutdown unexpectedly; depending on the ore type and quality, downtime for a single shovel can be as much as $300,000 per hour.Electric rope shovels are one of the most critical assets in open pit mining. They are very large, complex machines with DC or AC motors, multiple reduction gearboxes (some of them complex planetary) and multiple large rolling element bearings. This complexity, combined with the tough 24/7 service, results in too much unplanned shovel downtime, which can affect the entire downstream process."

Jan 1, 2012

By C. Cristonffanini, S. Nazari

"In the past, simulation was considered to be an offline tool disconnected from plant operation. Advancements in the computation power combined with utilizing physics and chemistry sciences have allowed us to significantly improve the modeling and simulation technology for mining and mineral processing. This paper investigates the benefits of first principle models and simulation by connecting them to real time operation. Process data are connected to high fidelity models executed in parallel to the operation. In recent literature, this concept is known as Digital Twins. The Digital Twin is used for various purposes such as optimization, virtual instrumentation and condition monitoring. Using IDEAS™ simulation software we are able to construct a digital twin for different equipment inside a mineral processing plant. Two case studies for building a digital twin for the primary hydrocyclone feed pump and thickener underflow are presented. Using the pump’s model, a digital twin is developed and is installed in a gold extraction plant that is able to infer the slurry density in real time. Additionally, it is used for detecting sanding in the pipes and impeller condition monitoring.INTRODUCTION Since the eighties, thanks to advances in computation technologies, computer based simulation of processes using first principle models has become a well-known engineering tool for various industries. As our understanding of processes has increased, their representative models have become more realistic and more sophisticated. Due to this increase of accuracy, use of simulation is becoming more fundamental in process industries. The main goals to use accurate simulation is to decrease the engineering and construction cost, optimize the process design and improve the operation performance by decreasing operation cost and increasing efficiency. The term Digital Twin was first introduced in 2010 by NASA (Shafto et al., 2012) in aerospace industry. Subsequently, the concept quickly spread through other industries. As of today, no standard organization has provided an official and unique definition of Digital Twin for process industries. However, there are three important aspects that are common throughout various descriptions. When simulation is core functionality of the process (1) along the entire life cycle of the plant (2) with direct linkage to operation (3), it is called that process has a Digital Twin. According to Gartner, the concept of Digital Twin has elected as fourth most important disruptive technology for the year 2018 (https://www.gartner.com/, 2017)."

Jan 1, 2019

By E. L. Martheleur

Introduction In October, 1945, the Coal Division of the Institute appointed a Committee on The Use of Electricity in Coal Mines, with the following terms of reference: ?To study under which conditions in each deposit the use of electricity can be brought closer to the coal face and which types of electrical machinery can be recommended?. It was not until the beginning of this year (1946) that the Committee had a chance to convene and .discuss the conclusions which are embodied in this report. Mr. McLeod, as Chief Electrician of the Dominion Coal Company, is intimately concerned with that Company's installations, and Mr. McIsaac, as Electrical Inspector of Coal Mines for Nova Scotia, is well acquainted with installations in all coal mines in the Province. The knowledge of both has been very valuable in helping to draft this report.

Jan 1, 1946

By G. Danko, C. Lu

"High temperature and humidity at the working negatively affect safety and health in deep and hot underground mines. It is necessary to predict during design the dynamic changes in temperature with heat and moisture emitted into the mine ventilation-thermal-humidity (VTH) system from various sources such as auto-compression, wall of strata, mining equipment and workers. Currently available mine ventilation and climate models are either furnished with a simplified, step-change-type (SCT) model for thermal solver (such as in Climsim, VnetPC, Minevent, MFire, etc), or with more advanced models to account for the “thermal history effect” (also known as thermal flywheel effect), such as in Ventsim and MULTIFLUX. The goal is to quantify the modelling error caused by the lack of variable thermal history component in the SCT model. Two models are compared: one with and one without the thermal history component in long, single airway examples with long-term climate simulations for 20 years assuming an input air temperature with daily variation. The examples illustrate the magnitude and the time-lag phase of the variation of the modelling errors with space, time and model conditions. Large errors are shown in the order of +14°C and –7°C errors, persistent for long time periods, up to 20 days in one example.INTRODUCTIONIt is important to predict the heat and humidity distributions during the design of hot and humid underground mines for the safety and health of the workers. The feasibility of extracting a rich deposit in great depth may depend on the extent of ventilation and mine climatization for maintaining an acceptable working environment. The cost of ventilation and cooling may be substantial, up to 40–50% of the total energy cost of mining (Clausen, 2017). The accuracy of model solution is important in view of the low profit margin in mine feasibility for deep and hot mines. Safety and health of the miners, the primary concerns, are therefore inherently connected to finding ever better solutions in simulation methods and ventilation control techniques."

Jan 1, 2019

By S. Demetrio

China has a traditional segment of Copper Smelters with its own Chinese technology, typically small in size from 20.000 to 50.000 tCu/a, and they are responsible for the processing and production of more than 600,000 tonnes of blister copper per year. For occidental experts, like one of the authors, it is not so easy to believe that they are profitable, because the size and the use of old Blast Furnaces, but they are with simple and effective production lines. The authors are convinced that China has a good alternative to improve theses old copper production lines with small innovative changes in its process arrangement, jumping to higher level technology, more efficient in production, productivity and cost, assuring copper as a raw material for the country and its high speed development. The key to improve that the traditional Chinese Copper Smelter is white metal as an extra raw material as a first step doubling the copper production from raw materials and the complete replacement of concentrates by white metal (WM) in a second step increasing it four times or more as the final goal. It is not so difficult nor expensive to make it happen, but there are a couple of questions for implementing this innovation in the copper smelter industry: 1 - Will the old fashioned mentality be open to this new direction for China being the biggest copper consumer on one side, and the biggest copper Primary Producers on the other hand? and 2 - Will they be open to follow this "win-win" strategic way for both ends of the copper market? We don't know if anybody will take up the challenge to improve it but our responsibility as a consulting expert and a university professor is to put the alternative on table for others to decide whether to implement it.

Jan 1, 2007

By Desmond Y. M. Lee

This paper presents a procedure to prepare input for the computerized pit design system at Iron Ore Company of Canada. The procedure is simple and requires very little training. Also, it is general enough to accept both bench (horizontal cross section) maps and section (vertical cross section) maps. The output of this procedure is data which represent blocks of ore and waste with dollar values based on mineral content. The ultimate pit design is presented in printer-generated graphs, with numbers indicating the depths of pit bottom walls. Roads are added manually by the engineer with the aid of other computer programs. Section maps and bench maps are also printed as part of the output of the ultimate pit design.

Jan 1, 1978

"Real-time, on belt analysis of minerals is becoming increasingly important and critical in modern operations, especially in the mine-to-mill. Prompt gamma neutron activation analysis has long been utilised for real-time elemental analysis in bulk materials, with Scantech's GEOSCAN being the instrument of choice in the minerals sector. Working in the minerals space for 15 years, the GEOSCAN has been successfully implemented in a wide range of minerals applications including iron, copper, lead-zinc, manganese, phosphate and more, and it caters for the very high demands and increasing requirements of a contemporary processing facility. An area of focus has been on increasing the analysis frequency to allow for rapid analysis results with the same high degree of accuracy typically expected of the GEOSCAN. This paper discusses the underlying research and technology that has enabled such rapid analysis and presents a range of examples using a thorough statistical approach on real production material, demonstrating achievable accuracy over a short analysis time, and dispelling common myths about the speed of the technique. Potential applications are discussed to conclude the paper.INTRODUCTION Technology and the information it can provide plays a critical role in the evolving modern mineral processing landscape. The importance of technology to analyse various features of ores and concentrates being processed is obvious, and recent years has seen the advance of numerous technologies to provide a variety of real-time measurements on conveyed material flows. From sampling apparatus to particle size analysis to weight and density meters to full elemental analysis, the availability of information enables a variety of improvements in the process leading to improved efficiency and increased revenue. To maximise the potential benefits, access to real-time information is imperative, and rapid updates of information become necessary to make appropriate process control decisions based on the most relevant and up-to-date information."

Jan 1, 2017

By Kosei Ishida

To achieve renovation work without noise, the authors developed techniques of manufacturing pre-cut interior finishing components for renovation work. In this paper, to achieve the system of pre-cut interior finishing components, the authors describe a measuring method of reinforced-concrete structure by 3D laser scanner and then describe a method of making a design of pre-cut interior finishing components with the polygon model. Using these two methods, the steps of manufacturing pre-cut interior finishing components consist of the following four steps: First, measure the building shape using a 3D laser scanner. Secondly, integrate a point cloud data and retrieve the markings on the floor. Then, create a polygon model of the building based on the point cloud data. Lastly, make a drywall design using a polygon model. To evaluate the technique feasibility of manufacturing pre-cut interior finishing components, the authors have conducted an experiment of the finishing interior work of the drywall. Using pre-cut interior finishing components, the authors have been able to achieve interior finishing work without noise.

Aug 1, 2013