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By Naizhong Xu

During the past 30 years, fully mechanized caving mining has played a positive role in the improvement of the efficiency of coal production, but which has also had a great influence on the mining environment, especially to environment damage of shallow mining areas in the central and western regions of China. The surface subsidence parameters are the basis of the surface environment evaluation and governance. During 1980~1990s of the last century in China, fully mechanized mining subsidence laws were researched more fully, however, since coal caving technology is affected by many factors, and researches on its mining subsidence laws (parameters) were found to be grossly inadequate. Through actually observed in recent years, it is considered that coal caving mining subsidence laws (parameters) can use fully mechanized mining law (parameters) for reference. Based on fully mechanized mining laws (parameters), this paper reveals the similarities and differences of the surface subsidence laws between fully mechanized caving mining and fully mechanized coal mining, which can guide the work of coal mining under buildings, water bodies and railways in new mine area and mine collapse governance.

Aug 1, 2013

By Stuart J. Schofield

Introduction The study of the ore deposits of British Columbia is one of fascinating interest not only from a scientific but also from a commercial standpoint and certain wide problems in connection therewith have interested me for some years. Several of these problems have been set forth in papers presented before this Institute on previous occasions. In 1918 it was pointed out that the commercial ore deposits of British Columbia, with one exception, were associated with the granodiorite batholiths of upper Jurassic age. This was followed, in 1922, by a discussion of the ore deposits of British Columbia in which the mineral belts of the province were defined and named, showing a zonal arrangement of ores in which the Pacific coast deposits are characterized by the presence of copper, while the interior belt is marked by the presence of silver, lead, and gold. Methods Of Investigation In reading various reports on the economic geology of British Columbia one is struck with the fact that the mineral veins may be arranged as a system and further examination will show that such a system follows two main directions, one northeasterly and the other northwesterly, both related in origin to the same force.

Jan 1, 1925

By C. Han, S. J. Zhou, Y. B. Shen, D. Z. Wei, P. Fang

"Collecting property of two hydroxamic acid collectors have different type of nonpolar structure to hemimorphite has been comparatively studied via monomineral flotation test, and the reason causes different collecting performance has been discussed from the view of relationship between molecular structure and collecting property. The flotation tests results show that C5-9 hydroxamic acid has an unbranched linear alkyl nonpolar group shows better collecting property to hemimorphite than cyclohexyl hydroxamic acid which has a naphthenic nonpolar group. FTIR detecting results show that the adsorption type of collector adsorbed on hemimorphite surface is chemical adsorption. Calculation results of polar group’s geometric structure parameters, polar group’s electron density distribution, octanol-water partition coefficient (logP) and molecular frontier orbital energy show that the key factor caused different collecting property of two collectors to hemimorphite is the logP; unbranched linear alkyl nonpolar group is more conducive than naphthenic nonpolar group to make hemimorphite particle more hydrophobic.INTRODUCTIONZinc-bearing mineral recovered from lead-zinc ores is the main source that people can obtain zinc resource from nature. However, natural sulfide ores are currently getting depleted steadily for the primary zinc source. In order to satisfy the future demand of zinc resource, there is an obvious recognition that the recovery of zinc oxidized minerals from the ores is a crucial alternative (Hosseini & Forssberg, 2007; Navidi Kashani & Rashchi, 2008).But the fact that can’t be ignored is the flotation of zinc oxidized minerals is much more difficult than that of zinc sulfide minerals, which is mainly due to the flotation characteristics of these zinc oxidized minerals such as lower selectivity and higher reagent consumption, as well as complex and variety of lead-zinc ores. Presently, there have been many various beneficiation technologies used for recovering zinc oxidized minerals and dealing with ores for recovering metallic zinc such as flotation and hydrometallurgy (Abkhoshk, Jorjani, Al-Harahsheh, Rashchi, & Naazeri, 2014; Önal et al., 2005). But from an overall perspective, flotation is the most common method used for the beneficiation of zinc oxidized minerals, and there have been extensive investigations conducted on the flotation of zinc oxide ores (Ejtemaei, Gharabaghi, & Irannajad, 2014). Until now, the most well-known method used commercially for the flotation of zinc oxidized minerals is sulfidization with sodium sulfide and flotation with a cationic collector of amines containing from 8 to 18 carbon atoms. However, a major problem for this method is the large amount of fines and slime results in the increase of reagent consumption and promotes the phenomenon of slime-coating. For preclude this negative effect, the de-sliming and processing optimization is indispensible (Peres, Borges, & Galery, 1994; Salum, de Araujo, & Peres, 1992)."

Jan 1, 2016

"During the development of a mining project, samples are taken for metallurgical tests. The sample can be a composite sample made of material from a selection of various drilling products or a sample from a mining test. It can be also a sample from an existing plant in order to investigate process enhancement. This sample can represent several tonnes of material which are analysed and split for use in various tests.In the current case, a composite sample of gold ore is dedicated to a Gravity Recoverable Gold (GRG) test. The properties of interest are the head grade of gold, the size distribution of the material, and the gold assay per size class. The sample is mixed and a sub-sample is taken to measure the feed properties: the size distribution and the gold assay per size class. The remaining material of the sample is subject to the first stage of concentration using the laboratory Knelson concentrator. The concentrate is analysed in its entirety, while a sample of tailings is taken for the same analysis. The remaining part of tailings is subject to grinding to feed the second and third stages of concentration. Similar sampling is performed at each stage.The concentration performances are analysed in light of these measurements. But what is the accuracy of the measurements of the properties? Pierre Gy’s theory of sampling, associated with a heterogeneity model built using the GRG test results, will answer this question. The current paper presents, through a real example, the calculation of the errors of the measurements of size distributions and gold assays performed during the GRG test. The uncertainties of the concentration performances and liberation size estimate are then calculated and their impact on the results interpretation is analysed.INTRODUCTIONDuring the development of a mining project, samples are taken for metallurgical tests. The sample can be a composite sample made of material from a selection of various drilling products or a sample from a mining test. It can be also a sample from an existing plant in order to investigate process enhancement. This sample can represent several tonnes of material which are analysed and split for use in various tests. In order to take into account the ore variability in terms of gold deportment, it is recommended to perform variability studies (Dominy, Murphy, & Gray, 2011, Dominy, 2013) using samples representing various horizons or years of production. But for a given ore type, it can be necessary to perform many tests with different operating conditions (Brochot, 2012a). In that case, the variability of the samples is not due to the heterogeneity of distribution of the deposit, but only on the heterogeneity of constitution of the primary sample. The level of confidence associated with the estimated performance parameters is directly linked to the overall error (including sampling error) of the measurements performed during the tests."

Jan 1, 2016

By K. G. Wheeland, K. G. Byberg

The occurrence of a secondary, dust-fuelled explosion following blasting of sulphide ores has been reported in mines in many countries, including canada, the USA, Australia and South Africa. However there has been little effort to document the events and develop effective control technology. Following a detailed investigation of an incident at the Geco Di vision of Noranda Minerals Inc. , the company held a conference of interested parties in October 1986 to review the state-of-the-art and to agree on action. '!his paper outlines the causes and effects of such explosions, the key conference points and conclusions, and subsequent information-exchange and teclmology-developrnent activities.

May 11, 1988

By Yasuo Iizuka

We have had studied CO oxidation on unsupported Au powder (mean particle size, ca.100nm) manufactured by evaporating ultra high purity gold metal (>99.99%) in inert gas and reported that it showed some activity after oxidizing pretreatment in O2 at 423 K?453 K. However, recent XPS analysis of the Au powder revealed that it contains much amount of impurity metals such as Ag and In at levels which far exceed those expected from the impurity level of raw gold metal in the bulk. Several samples of Au powder containing different amount of impurity metals were prepared to examine whether the activity depends upon the existence of surface impurity or not. Activity measurements were performed at 273 K after undergoing the powder under various pretreatment conditions. Although the activity of Au powder varied to some extent according to the pretreatment condition, it is strongly correlated to the surface concentration of Ag. Such dependence was not found for In, indicating that the activity of unsupported Au powder is mainly due to the existence of Ag in the surface layer. The activity attributable to ?particle size effect? was not recognized for Au powder with a mean particle size larger than 80 nm.

Oct 1, 2003

By Jean-Luc Collins

"This paper shows how simple reliability concepts such as mean time between failures and mean repair time can be used efficiently to help increase equipment availability and so reduce the economic losses associated with unreliability.More specifically, the paper shows how these simple concepts can be used in maintaining an appropriate balance between fleet failure and repair rates and how they can be used for setting up priority repair rules f or queuing equipment.IntroductionA profitable mining operation must handle large quantities of ore and waste at the lowest possible cost. To achieve this objective, the operation must optimize the productivity of its fleets of equipment by efficient management of the time element. Figure I shows some basic equipment activities in an open pit operation while Figure 2 shows a tree diagram describing some time elements of these activities.It should be noted that the only time a piece of equipment can generate a profit is when it can be found in the operating status. In order to maximize this time element, the sum of the other time elements must be minimized because the total time is always fixed.This paper shows the application of simple techniques capable of reducing the waiting time for repair (maintenance delay) by using simple reliability concepts."

Jan 1, 1988

By Eric D. Marks

Fatalities resulting from ground workers colliding with objects and construction equipment accounted for approximately 18% of the total construction fatalities experienced in 2010. Current injury and fatality measuring methods have proven to be inadequate due to their use of passive measures of safety rather than a more active approach, such as the use of leading indicator data (also called near misses) of hazardous proximity situations between ground workers and heavy equipment on construction sites. The objectives are to create and evaluate the effectiveness of a reliable algorithm for collecting and analyzing the resulting leading indicator data from hazardous proximity situations. Numerous experiments emulating typical interactions between workers-on-foot and heavy equipment are used to evaluate the proximity sensing and detection technology. Safety leading indicator data (also called near misses) generated by the proximity sensing and detection technology during the experimental trials are used to create and assess the resulting algorithm. Results from the experiments indicate that leading indicator data generated from these systems can be processed and analyzed to identify hazardous proximity situations and incidents on construction sites.

Aug 1, 2013

By Craig Faulkner

Discharge cones for large Semi Autogenous Grinding (SAG) and Autogenous Grinding (AG) mills are subjected to high wear as significant volumes of ground ore and slurry exit the mill. With the larger diameter mills of 32ft to 40ft in size becoming the norm, very high, concentrated wear is highlighting the limitations of conventional discharge cones and frequent changes are subsequently required. This paper outlines the advances made in the design of the Bullnose discharge cone. Superior wear materials to increase wear life over conventional rubber or chrome-moly steel discharge cones and the introduction of key design features to reduce reline times and improve fit and safety during installation, offer significant opportunities for the mill operator. Collated from multiple case studies, the wear data and reline history from 2004 to present clearly illustrate the way in which superior component longevity has reduced the frequency of relines over the life of the product to increase mill availability and effectively increase the tonnes milled in a period.

Jan 1, 2012

By Yugo Mitani, Tatsuya Kato, Chiharu Tokoro, Abdullah Al Mamun

Acid mine drainage (AMD), which is a major source of mining pollution, often contains ferric and/or ferrous ions together with several toxic elements. The ferric and ferrous ions in AMD precipitate in several mineralogical forms after neutralization, and the ferric/ferrous precipitates become the main component of the sludge generated after AMD treatment. The precipitates are also good absorbents for several toxic elements. To avoid generation of voluminous sludges and the re-dissolution of toxic elements from the sludge, it is very important to generate well-draining and efficiently adsorbing sludges by controlling the mineralogical form of the ferric/ferrous precipitates. Green rust, which is ferric and ferrous hydroxide, is a double layer hydroxide which is able to sorb several toxic elements. The green rust transforms to goethite or lepidocrocite by rapid oxidation, whereas it transforms to magnetite at ambient temperature by slow oxidation. The magnetite is also good absorbent especially for toxic cations and it makes a compact sludge due to its magnetic properties. We investigated the magnetite generation process at ambient temperature in detail. The magnetite generation process can be divided into three steps; (i) oxidation of Fe(II), (ii) Fe(II) surface complexation to Fe(III) hydroxide, and (iii) crystallization of magnetite. More magnetite can form when the oxidation rate is slower than the crystallization rate, and optimum conditions for its formation are at pH 9.5 with mild agitation. Ferrihydrite is the most common precipitate and it is able to sorb many different toxic elements. However, it drains badly and its solid/liquid separation properties are poor. We investigated the removal mechanism of several toxic elements by co-precipitation with ferrihydrite. We confirmed that the removal mechanism by co-precipitation partly involved surface precipitation when the initial ratio of toxic elements to ferric ion was high, although the main mechanism was always surface complexation. When surface precipitation occurred, highly efficient toxic element removal with ferrihydrite could be achieved.

Jan 1, 2016

By W. R. Bacon

"IntroductionTHIS IS a brief discussion of certain regional and economic aspects of the Coast Range of British Columbia. Between Portland canal and the 60th parallel of latitude, only the eastern margin of the Range is in Canada. The solely British Columbia interval extends from Portland canal to Burrard inlet. Personal observations in various parts of this area form the basis for much of this paper.Regional GeologyGranitic RocksSome of the best, most continuous exposures in the Coast Range are found at sea level. Reconnaissance study of the coastline has shown that the Range is predominantly granitic in character, but there simplicity ends, for the term 'granitic' as applied to the Coast Range covers a variety of mineralogical compositions. Actual granite is quite uncommon, occurring mainly in irregular or dyke-like masses that do not achieve batholithic dimensions. It is commonly pinkish, relatively homogeneous, and exhibits few of the deformational features that are obvious in much of this plutonic complex.Most of the granitic rocks of the Range fall well within the compositional limits of quartz diorite and granodiorite. The problem of resolving the great mass of these rocks into smaller coherent units is in general a difficult one. As noted above, granitic rock of uniform composition and texture is found in restricted areas and can be outlined without much difficulty. One such body occurs on the southern shore of Nelson island."

Jan 1, 1955

By Tao Cheng

Previous research and applications in construction resource optimization have focused on tracking the location of material and equipment. There is a lack of studies on automated monitoring of the interaction between workers and equipment for safety purposes. This paper presents a new approach for measuring the safety performance of construction personnel particularly when they work in very close proximity to moving equipment as well as static hazards such as chemical and flammable substances. A method of generating hazardous zones according to the geometric and kinematic characteristics of the considered hazard is introduced. The spatio-temporal relationships between the hazardous zones and workers? positioning data collected by real-time location sensing technology are automatically analyzed. This approach has been validated in a controlled test bed environment that simulates a construction site. Results indicate that worker?s safety performance of selected activities can be automatically and reliably measured using the developed approach. Furthermore, a heat map is generated for visualizing proximity related issues in the test bed using the computed results.

Aug 1, 2013

By K. E. Harley, M. J. Whiting, T. J. Sabin, E. M. Ryan, J. F. Watts

"Wire and Arc Additive Manufacturing (WAAM) has the potential to enable a very significant reduction in buy-to-fly ratio compared to conventional manufacturing through the ability to build near-net shape components. Components manufactured from AA 2319 by WAAM can exhibit significant levels of porosity. There is also a variation in the physical appearance of the surface deposit sometimes found on such components. This deposit is similar to those observed on aluminium joined by MIG and TIG welding processes. It has been suggested that both the bulk porosity and the surface deposit are caused by hydrocarbon-based lubricant on the feedstock wire. An established correlation between surface deposit and porosity would offer valuable insight into WAAM products and enable early interventions in quality control or process monitoring based on visual examination. The relationship between the nature of the surface deposit and porosity has been studied for AA 2319 WAAM components manufactured using different wire batches. Evidence is presented to support the assertion that (i) there does not appear to be a relationship between surface deposit coverage and porosity, (ii) batch-to-batch variability in feedstock wire affects porosity. This study has led to a better understanding of the cause of porosity in WAAM components.INTRODUCTION There is a high cost associated with conventional, subtractive manufacturing because of the high ‘buy-to-fly’ ratio, a measure of the initial material bought compared to the material found in the finished part (Allen, 2006; Yilmaz & Ulga, 2016). A typical aerospace product may have up to 90% of the purchased billet of forging machined away which is cost inefficient and high in material waste. Wire and Arc Additive Manufacturing (WAAM) has the potential to reduce costs and lead time. Robotically controlled weld torches rapidly deposit feedstock wire in layers to build large near-net shapes with mechanical properties similar to those of conventional manufactured parts (Sequeira Almedia & Williams, 2010; Martina et al., 2012; Ding et al., 2015; Williams et al., 2015). A high level of porosity variation has been observed in aluminium WAAM parts (Cong, Ding & Williams, 2014; Gu et al, 2016) which can result in a range of material properties (Rudy & Rupert, 1970). This leads to difficulties in regards to standardisation and qualification of process and parts. In order for WAAM to be used commercially, porosity will need to be understood, monitored and reduced to a reproducible acceptable level or eliminated."

Jan 1, 2018

By John E. Udd

"In this paper the author presents the results of the 1992 CIM survey of graduates in minerals and technology programs in Canadian post-secondary institutions. As usual, the trends are out-of phase with the economic state of the industry. People who chose a minerals career in the prosperous days of the late 1980sare now entering a labour market in recession.The cyclical nature of enrollments is illustrated in a series of figures showing the trends since the CIM survey Wa5 begun in 1956 (and even earlier for mining engineering).In the survey, the respondents were asked to provide comments on their perceptions of the problems specific to minerals education in Canada. The large number of responses have led the author to the conclusions and recommendations given in the final part of the paper."

Jan 1, 1993

By E. R. Landry

This paper reviews the current state of electric furnace technology, with emphasis on some of the more recent developments. A large section of the paper is devoted to the use of increasingly high power inputs by arc furnace operators. Operating practices are then covered, including some of the newer techniques which have been tried.

Jan 1, 1967

By J. A. Reid

THE views and observations expressed herein on this old but constantly recurring question are our own, no effort having been made to align them with standard texts. Therefore, while they may find general acceptance amongst fellow engineers, they must stand as personal opinions and as such are open to debate and discussion. In order properly to consider the subject, it should first be 'set in proper perspective. Why are Prospects Examined? Prospects are examined to determine whether they may contain economic concentrations of metals or minerals, the legitimate mining business being run, pretty largely, to make money. Next to food and clothing, modern civilization is based on metals, with which are included in this discussion minerals, oils, and fuels. A constant and increasing demand for the common metals requires the location of replacements for depleted orebodies, while the use and appreciation of new metals brings increasing demand for them. Aluminium is a good example of a metal which has, within recent years, made great progress. Today, we are becoming increasingly aware of magnesium, chromium, tungsten, thallium, and other lesser known, metals.

Jan 1, 1945

"The Society for Mining, Metallurgy, and Exploration (SME) Inc. developed a guide of minimum standards for reporting exploration results, mineral resources, and mineral reserves for the purpose of informing the general public. The SME Guide has been adopted by the Society.History1. In 1988, at the request of members of the Society for Mining, Metallurgy, and Exploration (SME), Inc., the President of SME formed Working Party #79, Ore Reserve Definition, with the mission to develop guidelines for the public reporting of exploration results, resources, and reserves. A Subcommittee was appointed by the Working Party to draft these guidelines and submit recommendations to SME. The Subcommittee's recommendations were published by SME in the April 1991 issue of ""Mining Engineering"", and as a document entitled ""A Guide for Reporting Exploration Information, Resources, and Reserves"" (the SME Guide) in January 1992. Work continued on an ad-hoc basis until 1996, when Working Party #79 was renamed the SME Resources and Reserves Committee and became a standing committee.In 1994, the Council of Mining and Metallurgical Institutions (CMMI) started a concerted international effort to create a set of international definitions for reporting mineral resources and mineral reserves. An ad-hoc International Definitions Group was formed, with representatives from mining and metallurgical institutions from the United States (SME), Australia (AusIMM), Canada (CIM), the United Kingdom (IMM) and South Africa (SAIMM). A major breakthrough came on October 18, 1997 when the CMMI International Definitions Group met in Denver, Colorado and reached a provisional agreement (the Denver Accord) on definitions of mineral resources and mineral reserves. Concurrently, and since 1992, the United Nations Economic Commission for Europe (UN-ECE) was developing an international framework classification for mineral resources and mineral reserves. Starting in October 1998, joint meetings were held in Geneva between the CMMI International Definitions Group and the UN-ECE Task Force, resulting in agreement to incorporate the CMMI definitions into the UN framework classification."

Jan 1, 2003

By Alessandro Navarra

Discrete event simulation provides a computational framework in which the use of smelting equipment can be analyzed and optimized, leading to the development of alternative modes of operation. Much of the complexity of copper and nickel smelters is centered on the converter aisle. These converters operate in parallel, produce batches, and set the tempo for the downstream operations. In practice, smelter staff schedule daily operations to coordinate the smelting furnaces and converters with downstream operations. Thus, a realistic simulation of smelter operations, over hundreds of days, should incorporate converter scheduling algorithms as presented in this paper.

Jan 1, 2014

By Zhigao Xu, Ruan Chi, Zhenyue Zhang, Yaoyang Ruan, Zhengyan He

Weathered crust elution-deposited rare earth ore is a specific rare earth resource in China that is rich in middle and heavy rare earths. From surface to bottom, the weathered crust elution-deposit rare earth ores can be divided into humic layer, completely weathered layer, partly weathered layer, and bedrock. The exchangeable rare earth ions mainly exist in the completely weathered layer and partly weathered layer, and the exchangeable aluminum ions mainly exist in the humic layer. A novel solution injection method for use in the in-situ leaching technology of weathered crust elution-deposit rare earth ores was put forward based on the different distributions of RE3+ and Al3+ in the four layers. Avoiding the humic layer, only the completely weathered layer and partly weathered layer were leached by controlling the height of the leaching solution liquid level. In this way aluminum, the primary impurity in the RE leaching solution, can be decreased and the purity of the RE product can be improved. Meanwhile, the choices of available leaching reagents were broadened and the possibility of landslide disasters could be reduced.

Jan 1, 2014

"This document sets out the Exchange’s expectations and requirements for a valuation of mineral properties and outlines: the general purpose of valuation reports; guidelines respecting circumstances where the Exchange will require a valuation report; and valuation standards, guidelines and methods that are generally acceptable to the Exchange, 1. IntroductionThis Appendix sets out the Exchange's expectations and requirements for a valuation of mineral properties and outlines:(a) the general purpose of valuation reports;(b) guidelines respecting circumstances where the Exchange will require a valuation report; and(c) valuation standards, guidelines and methods that are generally acceptable to the Exchange.Mining industry standards and guidelines for valuations and valuation reports can be found in the Canadian Institute of Mining, Metallurgy and Petroleum Standards and Guidelines for Valuation of Mineral Properties (""CIMVal"") published in February, 2003 (www.cim.org). CIMVal consists of two parts, Standards and Guidelines. The Standards are mandatory and must be followed in order for a valuation to be CIMVal compliant. The Guidelines in CIMVal are not mandatory, but are strongly recommended.The Exchange requires that CIMVal Standards be used by Issuers and their professional advisors when preparing valuations and valuation reports on mineral properties. The CIMVal Guidelines should be followed by Issuers and their professional advisors in preparing valuation reports on mineral properties, with the exception that the valuation methods and guidelines under Section 4 Acceptable Valuation Methods and Guidelines below, must be followed."

Jan 1, 2003