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By John E. Tilton

During the past several years — much to the delight of producing firms and countries — copper prices have surged from under $1 to more than $3/lb. Anyone familiar with the industry also knows that since the early 1970s the long-run trend in real copper prices has been significantly downward. This sharp contrast between short-run and long-run trends raises the issue of the forces behind these developments. What has been driving short-run prices up and long-run prices down? Simple economics suggests that it is all a matter of supply and demand. When demand is rising faster than supply, prices will rise and vice versa.

Jan 1, 2006

By K. C. Tran

This paper reviews the advancement of measurement technologies for the control of raw materials processes in the basic industries. The combination of digital technology and on line spectroscopy enables the development of intelligent instruments for composition and particle size analyses in real- time high- frequency control conditions. In many industries, the applications result in productivity improvement and energy savings. Plant specific examples include operating experience and benefits realized in sorting, blending and beneficiation processes. Instruments of the future not only measure specific parameters of the process and monitor its own health combined with self-corrective mechanics but also acts with intelligence to effect the quality of the process or regulate the primary apparatus.

Jan 1, 2001

By J L. Mauk

Gladstone Hill, a volcanic-hosted low-sulfidation epithermal prospect in the Coromandel Peninsula, is less than 1 km from the world-class Martha Hill Au-Ag deposit. Gold-silver-bearing quartz veins occur in Late Miocene andesitic volcanic rocks of the Waipupu Formation that are extensively altered. The occurrence, spatial distribution and temporal relationships of hydrothermal minerals have been determined along two cross sections that transect the Amaranth, Gladstone, Cowshed and Moonlight veins. Quartz and pyrite are ubiquitous along these sections. Adularia and chlorite are widespread, but both are scarce in wall rocks adjacent to the Moonlight and Cowshed veins. By contrast, rare hydrothermal albite and epidote are restricted to wall rocks surrounding the Amaranth vein. Illite, which replaces adularia, is widespread and grades laterally eastwards into a zone of interstratified illite-smectite that envelops the Moonlight and Cowshed veins. During late-stage hydrothermal activity, rare calcite formed at depth and uncommon kaolinite and alunite formed at shallow levels. The overall clay mineral zonation with illite grading eastward into interstratified illite-smectite reflects paleothermal gradients of >220¦C to -170¦C towards the margin. The alteration assemblage of quartz, adularia, chlorite, albite, epidote, illite, interstratified illite-smectite and pyrite reflects formation from a near-neutral to weakly alkaline pH chloride water that contained low concentrations of CO2, Late calcite formed from very local descending steam-heated CO2rich water, whereas the rare assemblage of kaolinite and alunite formed from shallow steam-heated acid-sulfate water. Analysis of the available data indicates that the Martha Hill deposit and the Gladstone Hill area formed within a single large geothermal system. We infer that the Martha Hill deposit formed in the main upflow zone, whereas the Gladstone Hill area may have formed adjacent to this upflow zone.

Jan 1, 2001

Integrated Utilisation of Desulfurisation and Skimming Slag

Sep 13, 2010

By C A. Myburgh, S Craig, K Deb

In focusing on open pit mine scheduling, one of the biggest areas that a mining engineer can add value is in the area of cut-off grade optimisation. It is not atypical to add up to an extra 20 per cent in value by bringing forward higher-grade ore and deferring costs into the future.There are many techniques available to maximise net present value (NPV) when applied to open pit mine scheduling. That in itself raises the question of why so many of these techniques exist. The short answer is that none of these techniques are robust. Every time the problem changes, the algorithms also have to change.Instead of trying to make a problem fit the constraints of an existing technique, there is much to be said for usefully hybridising different approaches. This paper describes an innovative approach where evolutionary algorithms are combined with both local search and linear programming. The goal is maximising NPV through optimisation of cut-off grade policy and extraction sequence for an open pit mine. The cut-off/cut-over grade policy produced caters for multiple processing streams and stockpiles.Finally we demonstrate the quality of the algorithm by comparing some results with a well-known mathematical solution.CITATION:Myburgh, C A, Deb, K and Craig, S, 2014. Applying modern heuristics to maximising net present value through cut-off grade optimisation, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014, pp 155–164 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By S. H. Ash

A CLAY, sand, and gravel deposit known as the "buried valley" of the Susquehanna River is situated in the Northern field of the anthracite region of Pennsylvania near Wilkes-Barre. The presence of this buried valley and the uncertainty regarding the extent and physical condition of the water-bearing valley-fill deposits have made great care necessary in mining operations to avoid breaking the strata between the mine workings and the valley-fill deposits to the extent that inundation of the mine workings would follow. The principal factor that threatens to cut short the life of the anthracite industry, to curtail production, and to affect the economic structure of the people and business dependent on anthracite for their livelihood is inundation of anthracite mines (6,7).3

Jan 1, 1950

By G. D. West, J. D. Purdue

"Marked Ball Wear Testing (MBWT) employs identified grinding balls which are placed in an operating mill for a period of time, retrieved from the mill, and then measured to determine the amount of wear experienced. This is an excellent method to evaluate the relative differences in the wear rates of various grinding ball materials and/ or manufacturing process variables simultaneously and under actual production milling conditions. This paper outlines the methods of ball identification, testing and evaluation procedures and discusses the strengths, weaknesses, and proper application of marked Ball Wear Test results. INTRODUCTIONThe consumption of grinding media in the mineral processing industry represents a substantial cost to the comminution process. Grinding media is most often found to be the second highest consumable cost next to energy. To determine the selection of the most cost effective media, one must determine the specific wear mechanisms present in a given grinding application and decide which media system addresses these mechanisms most economically.A MBWT has definite advantages over other methods used to evaluate the relative consumption rates of grinding media. It allows the comparative testing of a large number of different ball types under identical operating conditions in a very short period of time. In addition, production wear rates can be accurately predicted directly from MBWT results. Typical MBWT test periods are in the order of 350 to 700 operating hours for high wear rate application and upwards of 2000 or 3000 hours for low wear rate applications. These times are much less than the 5000 or more hours required to purge a mill of the incumbent ball charge (to convert it to the test ball) and then provide even a minimal test period in which to conduct a full production test, for just one type of ball. Under production test conditions the evaluation of competitive product or the development of improved grinding balls is necessarily slow."

Jan 1, 1991

By Jim Nickerson, James McCleish, Tom Abkemeier, Nicholas Willig

The purpose of this project is to convey sanitary sewage from an existing pump station to a new waste water treatment plant. This paper will discuss the design and construction aspects of the project. The scope includes construction of three main shafts ranging from 34 to 100 feet in diameter at depths of 200 to 230 feet and 21,000feet of tunnel. Shaft construction consisted of slurry wall excavations keyed into claystone and limestone at depths ranging from 114 to 130 feet, followed by rock excavation utilizing drill and blast methods. The tunnel is being excavated in the Warsaw and Salem shale and limestone formations utilizing a 12'-6" diameter Wirth hard rock TBM.

Jan 1, 2005

The Determination of Sound Exposures (DOSES) software was developed by the National Institute for Occupational Safety and Health (NIOSH) specifically for use by mine management and safety personnel. DOSES simplifies the record-keeping and analysis associated with time-motion studies and worker noise exposures, making it easier to identify and solve noise problems. The software relies on a time-motion study that profiles the worker?s daily activities. At the same time, noise measurements are collected with a dosimeter or sound level meter (SLM). Observations about the worker?s location and tasks or other activities are recorded along with times and durations so they can later be matched up with the noise data. After the completion of a time-motion study of the worker?s daily tasks and locations (possible noise sources), which measures the worker?s noise exposures during the recorded events, the information is entered into DOSES. The program then displays information about the worker?s accumulated noise dose over time.

Jan 1, 2009

By D. Tesh

The mining industry worldwide is facing a tremendous shortage of minerals engineers in all fields of specialization. For instance, in Australia the skills shortage in the mining industry has been identified as one of the top risks facing the mining industry. In Namibia most minerals engineers employed are expatriates, with some being Namibians who studied abroad. The minerals engineering programmes at the Polytechnic of Namibia are still in their infancy. These programmes were designed to meet the mining industry skills needs. Being young has its advantages in that lessons can be learnt from older minerals education institutions that went through similar challenges. However, this does not imply just copying and implementing their approaches, since the context differs and, to ensure sustainability of the minerals education programmes, curricula have to be customized to the local context. This paper reviews the interventions made by the Polytechnic of Namibia in order to ensure the sustainability of its minerals education programmes. The methodology consisted of an extensive literature review, a status quo analysis of the mining and process engineering department, identifying the gaps between the current state and desired state, and mapping the goals and strategic actions required to progress to the desired state. The following factors were identified as major threats to the sustainability of minerals education at the Polytechnic of Namibia: the quality of students, low student enrolment rates, low pass rates in science and mathematics, shortage of academic staff, dwindling government funding, and limited involvement of the mining industry. The major outcomes of this research comprise the detailed strategic actions employed by the Polytechnic of Namibia to address the threats to sustainability of its minerals education programmes.

Jan 1, 2014

By Ö. Uysal

This study deals with the presentation of the mechanized longwall mining project introduced some years ago to increase productivity and output of Aegean Lignite Establishment (ELI) owned by Turkish Coal Enterprises (TKI.) and the comparison of this method with a planned alternative new mining method called ?shortwall mining? where continuous miners will be introduced as primary coal excavation machines. Following the planning phase, production costs have been calculated for both mining methods on the basis of a panel having a height of 7.5 m. In addition to cost analysis, both methods have been evaluated using ?the multi-dimensional objective system?. In this evaluation the value synthesis has been carried out according to scoring models. Lastly, the advantages and disadvantages of both production methods have been stated by analysing them according to related criteria. In the light of outputs gathered from the analyses, it has been determined that the shortwall mining method will out perform the longwall method. Keywords: continuous miner, shortwall mining, longwall mining, multi-dimensional objective system.

Jan 1, 2006

By H. K. Lin

Residual cyanide in cyanidation tailings can be detoxified by its oxidation to cyanate, as in the Inco and Degussa processes. However, cyanate, the product of detoxification and other oxidation processes, may be reduced to cyanide in reducing environments, e.g., deepwater discharge of cyanidation tailings. This study shows that the reduc-tion of cyanate to cyanide occurs and that the reduction rate increases with decreasing solution redox potential. Solutions with lower pH favor the reduction rate. No significant difference was observed between the results of tests prepared with distilled water and seawater, and the presence of cyanidation solid tailings does not show an effect on the reduction. Because cyanate can be reduced to toxic cyanide, causing environmental concerns, the deepwater discharges of cyanidation tailings must be handled carefully.

Jan 1, 2008

By He De-wen

Based on the principle of life cycle assessment (LCA), municipal solid waste management (MSWM) was analyzed by life cycle inventory method. According to the system expansion and substitution method, the content and frame of life cycle analysis is summarized and applied to municipal solid waste. On the basic of feasibility research of life cycle analysis on MSWM, the paper put forwards complete and concrete ?three changes? measures under life cycle analysis on MSWM. Some aims of MSWM can be achieved under above conditions of LCA on MSWM: to improve the current system efficiency of MSWM; to enhance the serve quality of MSWM, to increase recycle garbage from MSW; to reduce waste amount and reach minimization and innocuity aim of MSWM; to help the departments of MSWM to get over all difficulties to realize their ideal goals.

Jan 1, 2009

By P. G. Roden, G. A. Maki, P. J. Fullmann

"In October 1984, Rocanville Division began using a stacking system to handle potash mill tailings. Previous to this date, mill tailings were slurried to the top of the tailings pile and allowed to debrine while flowing mobile stackers. The stackers consist of cyclone packs to debrine the tailings and drag conveyors with screw discharges to deposit the tailings onto the existing pile. The paper will deal with the various aspects of the project from conception to its present state. Key Words: stacking, mobile stackers, Linatex Separators, potash mill tailings, reclaim brine ponds, settling ponds, tailings pile. IntroductionPrevious to 1984, when the stacking project was first implemented, potash mill tailings were handled as follows. Mill tailings were first debrined to approximately 65% solids using a cyclone cluster. The cyclone underflows were then introduced onto a vacuum scroll filter table. Here the tailings were further debrined and discharged into the disposal tank where the tailings were reslurried with reclaim brine and pumped to the tailings disposal site. At the disposal site the slurry was discharged onto the tailings pile and by a natural settling process the tailings were debrined with the brine ultimately collected in the reclaim brine ponds. The shape and profile of the tailings pile was controlled by building salt dikes to control the flow of the discharged tailings slurry. As the tailings pile grew in height, booster pumps were added to the disposal system."

Jan 1, 1986

By Clayton M. Rumsey

The U.S. Bureau of Mines conducted a mineral resource survey of the Cinder Cones Wilderness Study Area (WSA) (CDCA-239), 10 miles east of Baker, CA, in 1983. The 44,299-acre WSA is underlain by Precambrian granite gneiss, Upper Cretaceous or lower Tertiary Teutonia quartz monzonite, and Quaternary basalt flows and alluvium. This mineral survey included an examination of two volcanic cinder mines, five lode prospects, two volcanic cinder prospects, and reconnaissance sampling in and near the WSA. The seven prospects are in the WSA; the two volcanic cinder mines are adjacent. No mines are in the WSA. In 1981, there were 61 placer and 3 lode mining claims in the WSA. Sample results from two prospects within the WSA contained significant gold and silver values; however, the mineralized rock is of limited extent and no resources were apparent. Alluvial samples taken throughout the WSA contained only traces of gold. Two volcanic cinder cones within the WSA contain an estimated 30 million tons of cinders. There are sufficient cinders outside the WSA to satisfy demand in the foreseeable future. Stone, sand, and gravel deposits are not resources because similar material is closer to markets. No evidence of energy minerals or geothermal resources was found.

Jan 1, 1985

By P Allen, E Gleeson, D Boakye, R Chesher, S Konopa

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Not only do epithermal gold deposits provide many challenges in estimating mineral resources, the complexities of these deposits also provide technical challenges in assessing appropriate mining and processing strategies, as well as social and environmental planning and management. The characteristics of epithermal gold deposits include being highly variable with respect to geometry and gold grade distribution, the presence of other economic contributors, mineralogy, texture, rock strength, weathering and alteration overprint. These characteristics influence the economic value of mining projects in an interlinked manner. Consequently, successful exploitation of epithermal deposits requires a holistic approach, coupled with the effective integration of geological data to meet all aspects of mine development decision-making. This paper presents examples of the key technical challenges encountered in estimating and mining epithermal deposits. It also highlights why these issues need to be addressed from the viewpoint of geology, sampling, resource estimation, mine planning, mineral processing and social and environmental planning for the true value of the mining project to be realised.CITATION:Konopa, S, Chesher, R, Gleeson, E, Allen, P and Boakye, D, 2015. Challenges in maximising the value from epithermal gold deposits, in Proceedings PACRIM 2015 Congress, pp 127–132 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By W. P. Yant

Canister-type gas masks Pave become an essential part of the equipment of many industries, not only for use in .emergencies, but also in performing normal operations of industrial processes and procedures, particularly where ventilation is not practically or economically feasible. They are also used widely for enhancing safety of operations which previous to the development of gas masks had been performed in harmful atmospheres. Since the inception of industrial gas masks the Bureau of Mines has been actively engaged in endeavoring to increase the efficiency and safety of these devices, and this bureau bas become a source of advice to manufacturers in producing devices of good quality and to industry in the proper selection and use of these devices. In order to give first-hand information and keep current with the demands and needs of industry it is necessary to perform investigations from time to time. This report deals with tests of certain types of commercial gas-mask canisters for protection against mercury vapor.

Jan 1, 1932

The Influence of Particle Shape in Rock Fracture

Sep 13, 2010

By Robert G. Gibson, Joel D. Gibbons

Measurements and analyses were conducted of whole-body vibration aboard seven commercially available passenger and/or recreational vehicles: sedan; sport-utility vehicle (SUV); pickup truck; moving truck; motorcycle; all-terrain vehicle (ATV); and boat. The purpose of the testing was to measure and assess whole-body vibration exposure in a range of typical vehicle environments in order to gain understanding of typical exposure levels characteristic of activities of daily living. Vehicle models tested (and model year) were: Ford Taurus (1995); Jeep Cherokee Sport (2000); Toyota Tundra SR5 (2002); Ford F-350 (1997); Harley-Davidson Electra Glide Classic (2004); Yamaha Kodiak 400 4x4; and Steiger Craft Model 21 Montauk. All vehicles were tested with their standard factory-installed seats and were operated under a range of normal operating conditions and speeds typical of intended vehicle use. Methods The measurement, processing, analysis, and exposure assessment methods follow the guidance of generally accepted, national and international consensus standards relevant to the evaluation of whole-body vibration, including ISO 2631-1 [1] and ANSI S3.18 [2]. Seats were instrumented with low-mass triaxial accelerometers mounted in seat pads. Accelerometers used in the test are specified to have flat frequency response over the frequency range of 0.5 to 80 Hz, and all accelerometers were recently calibrated traceable to the National Institute of Standards and Technology (NIST). Seat pads were installed following guidance in the relevant standards [1, 2], with sensitive axes of the accelerometers following the standard coordinate system with respect to the seated occupant. (The x-axis represents fore-aft motion; the y-axis represents side-to-side motion; and the z-axis represents vertical motion with respect to the occupant.) Vibration data processing and analysis, including filtering, sampling, frequency-weighting, averaging, summation, and determination of basic and additional metrics followed procedures in the relevant standards [1, 2]. Digitized time series data were acquired and stored using a PC-based data acquisition system. Whole-body vibration exposure analyses were conducted via post-processing. During data processing, recorded periods of seat acceleration that were identified and verified as resulting from occupant-induced motion rather than vehicle motion were excluded prior to exposure analysis. The basic evaluation metric for whole-body vibration is the frequency-weighted root-mean-square (r.m.s.) acceleration, aw. The primary additional evaluation metric is the fourth-power

Jan 6, 2006

By E. Esponosa-Gomez, J. A. Finch, A. R. Laplante

"Water quality plays an important role in oxide flotation. The effects on selective flotation of fine (1-16 um) pyrochlore of two types of water used at the Niobec concentrator, potable and plant recycle, were assessed. Several pyrochlore collectors and silicate depressants were tested. Water effects were different for each mineral-reagents) combination. In general plant recycle water decreased selectivity and increased reagent consumption. Interpretation of results is given in terms of electrokinetic effects, hydrolysis of cations, and mineral-collector interactions. Two techniques of treatment for plant recycle water, cation precipitation and zeolite adsorption were assessed. The former was found to be more effective under the tested conditions but recycle water continued to give poorer selectivity than the potable.INTRODUCTIONWater quality plays an important role in selective flotation. Specific effects have been reported by many workers (1-6) and in general the better the water quality the more selective is flotation. Water composition depends on origin and the minerals being processed. For example pulp containing salt-type minerals (calcite, apatite, dolomite) will contain more Ca and Mg cations than that from a sulphide deposit. Another source of water contamination is the flotation reagents added to the pulp, particularly if water recycling is practiced."

Jan 1, 1986