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By Haragobinda Srichandan

The present study aimed to investigate the bioleaching efficiency of moderate thermophilic microorganism in a growth medium without Fe supplement on three different size fractions of spent catalyst obtained from petroleum refinery. All the experiments were conducted on shake flasks at a temperature of 65 °C and a pulp density of 10% (w/v) on three size fractions viz. 45-106 µm, 106-212 µm and >212 µm and a working volume of 100 ml comprising of 10 ml of microbial inoculums and 90 ml of Modified Kelly medium. The parameters like pH, redox potential, viable planktonic cell count and the amount of acid addition was measured and quantified on regular basis to follow the progress of the bioleaching. The pH varied much in the lag and logarithmic phase of the experiments but stabilized toward the stationary phase. The total acid additions in each batch experiment were determined the amount of Conc. H2SO4 requirement, which ranged between 683-757 kg/ton of spent catalyst. The redox potential values ranged between 625-650 mV, Ag/AgCl, but were very low ranging between 350-450 mV during initial period. The planktonic viable cell count ranged between 108-109 cells/ml active in the bioleaching system, without any toxic influence of the spent catalyst, but initially due to fall in redox potential and new environment for the microbes, their population was low. The leaching yield of Ni was found to be promising with very high leaching yield of 92-96% followed by Al as 61-62%, which means both Ni and Al leaching were favored by the moderate thermophilic bioleaching compared to the mesophilic bioleaching. There was very little difference in the leaching yield, when compared with different size fractions and hence grinding can be avoided prior to leaching. This process seems to be economical as no Fe source is supplemented together with no requirement of grinding and over all a biological process resulting for an eco-friendly process for future optimization of the metal recovery from petroleum refinery spent catalysts. Keywords: bioleaching, spent catalyst, thermophile, 9K medium

Sep 1, 2012

By R. Sellaro

It has long been understood that extended occupational exposures to respirable mine dusts can lead to chronic lung disease. In underground coal mines, CWP and silicosis are major concerns. While there have been many studies aimed at understanding total dust concentrations and silica content associated with different mining conditions (e.g., locations/occupations within a mine, cutting methods, geologic strata), little research has been completed to more comprehensively characterize respirable dust (i.e., by particle composition, size distributions, shapes). This preliminary study sought to characterize dust from an underground coal mine in Central Appalachia using scanning electron microscopy with energy dispersive x-ray (SEM-EDX). Respirable dust samples were collected from various locations in the study mine, and individual dust particles were identified and classified by mineral type. A continuous personal dust monitor was also used to estimate total respirable dust concentrations during sampling. Here we report initial results of this work, and discuss advantages and challenges of particle-level characterization of mine dusts in terms of occupational health research.

Feb 23, 2014

By J Hadjigeorgiou, T R. Stacey

A ground support system is a combination of individual reinforcement and surface support elements that work together to retain and contain the rock mass. The various elements are subjected to external loads and to interactive loading between individual ground support system components. This paper focuses on the challenges in determining the capacity and behaviour of mesh, recognizing that installed mesh can be subjected to several loading mechanisms. Field observations from underground hard rock mines demonstrate that there are multiple types of damage and modes of failure of mesh. However, these are difficult to reproduce in a laboratory environment. A critical review has shown that existing mesh laboratory testing rigs reproduce very limited loading conditions that may not be representative of underground conditions. This has significant implications in quantifying and extrapolating the performance of mesh to ground conditions. CITATION:Hadjigeorgiou, J and Stacey, T R, 2018. Challenges in determining the capacity of mesh, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 280–290 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By H. F. Zurbrigg

Introdduction The main line of ascent in the development of the nickel industry may be traced back through the International Nickel Company of Canada, Limited, to its earliest antecedents, the Canadian Copper Company and the Orford Copper Company. Mining geology is but one aspect of the overall development of this organization, and the stress it has placed on geology grew according to the need. In the early days, intensive geology was not required because ore supply was not one of the main problems of this or any of the pioneer companies. The difficulty then was to find economic methods for reducing the ores to nickel and copper, and markets for absorbing nickel in the face of a limited demand from consumers heavily prejudiced in favour of the New Caledonia product. "Very early in the history of the region it was patent to everyone that to share in the full benefits of the industry the same individuals or company must control the whole of the operation necessary to manufacture the finished product' (1, p. 45). These conditions were fulfilled for the International Nickel Company in 1902 when the Canadian Copper Company (incorporated 1886), with its ample ore supply, took the initiative to merge its interests with those of the Orford Copper (Refining) Company (incorporated 1887) to form the new company which, with reorganizational changes, emerged as the producer of the overwhelming bulk of the world's nickel. The Mond Nickel Company, Limited, entered the field in 1899 with a refining process, and over a period of years acquired ore through purchase of mining properties. This Company operated successfully and independently until 1929 when its assets were joined with those of the International Nickel Company in order to permit the most economic exploitation of the Frood-Stobie orebody in which both Companies were interested.

Jan 1, 1948

By F. Matanzo

This guide considers only nine of the many wire rope terminations used in the mining industry so use of the information presented for terminations not specifically addressed can be done, but with some risk. The nine terminations considered are: Flemish Loop with Steel Sleeve & Thimble, Flemish Loop with Steel Sleeve, Wedge Socket, Swaged Socket, Turn Back Loop with Aluminum Sleeve & Thimble, Thimble Splice with Four Tucks, V-Bolt Clip with Thimble, Zinc Poured Socket, and Epoxy Resin Poured Socket. The guide uses pull test data, axial fatigue test data, and data on sensitivity to poor workmanship, to rank the nine terminations with respect to these performance measures. A selection procedure is suggested and illustrated with an example. Failure data is used to identify the common modes of failure of each termination and so help the inspector direct his attention to the likely location for a failure and describe what he should be looking for. The data on which this guide is based is included so that as new data becomes available, the ranking order can be adjusted accordingly.

Jan 1, 1978

By David E. Siskind

The Bureau of Mines recorded particle accelerations in the mine roof produced by three types of explosives in the Pilot Knob Pellet Co. mine, Pilot Knob, Mo. Examined were the effectiveness of cube root, square root, and two-thirds power scaling in grouping the underground blast vibration data, and the effects of mine geometry, rock type, explosive type, and charge size on blast vibration levels. A propagation law for this mine was determined. The scaling factor of the square root of the charge weight was developed from previous Bureau studies of vibrations from quarry blasts, and in under-ground blasting both square root and cube root scaling were found applicable for scaling particle vibration data. The vibrations from the Pilot Knob blasts were best grouped by a square-root scaling factor. The empirical propagation equation AW1/2 = 76,250 (R/W1/2)-2.61 where A is the peak acceleration in g's, W is the charge weight in pounds, and R is the distance from the blast in feet, may be used to describe vibration amplitudes from charges fired with zero delay caps or with a single cap at Pilot Knob. Statistically significant differences were found in the vibration levels generated by the different explosives. The Power Primer (75-percent weight-strength ammonia gelatin dynamite) produced levels of vibration of 1.7 to 2.4 times those of AN-FO and slurry explosives; the latter two are approximately equal.

Jan 1, 1973

By G. A. Parkison

The sequential copper analysis method is a particularly useful technique to semi-quantitatively define the geologic, mineralogic, and metallurgical types and zonations commonly associated with porphyry-type copper deposits. The method is based on the partial dissolution behavior displayed by the prevalent copper minerals malachite, chrysocolla, chalcocite, and chalcopyrite to solutions containing sulfuric acid and sodium cyanide. Results from sequential analyses of the sample and analytical residue using sulfuric acid followed by sodium cyanide and then aqua regia solutions when compared with conventional total copper analyses can determine the amounts of leachable oxide minerals, leachable secondary sulfide minerals, and primary copper minerals, respectively. Sequential assay analytical results and interpretation are presented for copper deposits in Chile, Mexico, and the United States.

Jan 1, 1995

By John B. Bennett

In this report estimates are presented of the impact of the passage of five recently proposed "acid rain" bills on electric utility costs for coal-burning utilities servicing the domestic aluminum smelting industry, and on the costs of production for affected aluminum smelters. As aluminum smelting is an energy-intensive industry, domestic increases in electricity prices could affect the industry's competitiveness. Energy costs in U.S. aluminum smelting are compared to aluminum smelting energy costs in the rest-of-the-world. Governmental policies affecting these energy costs are discussed.

Jan 1, 1988

By M Nagarajan, S Esen

This paper presents three case studies from three surface coalmines. The first case study is from a coalmine where a dragline operates in 60 m wide and 1 km long strips. Typical overburden height ranges from 30 m to 50 m. The base case blast was modelled using an advanced blasting model (Distinct Motion Code – DMC) to establish the baseline using the blasting parameters in use before optimisation. DMC was used to model the alternative blasting scenarios to obtain the following key objectives:the post-blast muck pile profile was required to have an optimum height of ~28 moptimise cast percentageachieve a well-fragmented muck pile for the draglinethe muck pile profile should be appropriate for the dragline entry into the strip.Achieving these objectives would optimise the dragline performance through reducing rehandle and improving advance along the strip. DMC modelling resulted in the following outcomes:the required muck pile profile could be achievedthe cast percentage increased from 21.1 to 25.1 – a four per cent increaserehandle volumes were reduced.Establishing a good quality assurance / quality control (QA/QC) process was essential to delivering a blast that could achieve these outcomes. The blast was fired successfully and the dragline completed the strip approximately two weeks ahead of the time taken for the previous strip.The second case study is from a coalmine where D11 dozers are used to move the blasted material to the spoil. An optimum profile was required for the dozers for this low-cost mining operation. To achieve this, an electronic blasting system (uni tronicTM 600) was introduced to optimise the muck pile profiles being delivered. The new muck pile profiles showed improved cast percentage from 10.6 per cent to 17.8 per cent. The changes in the muck pile centre of mass displacement improved dozer efficiency as a result of pushing material shorter distances to its final position. Dozer productivity (bcm/h) statistically did not change but coal was being exposed at a faster rate.The third case study summarises the results from a site where dozers are used to minimise the total mining cost. Traditionally, excavators had been used on-site with conventional blast designs. After firing the first cast shot, the blasted material was found reasonably well-fragmented. Although dozing productivity hasn’t been quantified on-site, operators were providing positive feedback (easier push) due to the reasonably good muck pile profile suiting to the dozers. This site also realised significant savings with the dozing as compared to their truck/shovel operation.CITATION:Esen, S and Nagarajan, M, 2015. Muck pile shaping for draglines and dozers at surface coalmines, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 409–416 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By Sebastiaan Peelman

NdFeB permanent magnets are the best available magnets used in many technology applications. However, at their end-of-life (EoL) most of magnets and the contained REEs are lost during the recycling of the bulk metals. The REEs are classified as the most critical raw materials in the European Union, and recycling of REEs from EoL products will reduce their criticality and contribute to the sustainability of REE. Various technological routes have been reported, but most of the methods are effective for highly concentrated magnets or magnet scrap, which is greatly dependent on expensive pre-dismantling processes. This paper presents various innovative metallurgical solutions to the effective REE recovery from current industrial practice for WEEE recycling, including the ferrous scrap from WEEE shredder products and shredder residues from computer hard disk drives. Both hydrometallurgical and combined hydro- and pyrometallurgical REE recovery routes are developed after demagnetization and physical upgrading.

By Sunil K. Tripathy

Particle characteristics such as size, density, liberation and magnetic susceptibility play vital role in magnetic separation technique. To understand the performance of magnetic separation process for chromite beneficiation industry, particle characteristics need to be analysed. However, to date, this has been an expensive and time consuming task, thus only minimal amounts of this type of data are available in the literature. Several new methods are being developed, that will produce the required mineralogical and liberation data to provide processing information rapidly and inexpensively. Among these, QEMSCAN is a unique and advanced characterisation equipment used for liberation analysis for different ore whereas S.G. Franz Isodynamic Separator for determining the magnetic susceptibility. In Indian chromite deposits, the content of iron bearing minerals in the ore is typical which controls the Cr:Fe ratio in the product while treating in gravity based beneficiation plant. In the present investigation, detailed characterisation of two distinct chromite ore samples from Sukinda chromite deposit, India, was investigated which includes advanced mineral characterisation using QEMSCANand magnetic susceptibility measurement by using Frantz Isodynamic separator, etc.. Presence of haematite and gibbsite along with chromite mineral were identified as major gangue minerals in the high grade ore from XRD pattern whereas Goethite, Quartz, Haematite, Kaolinite, Ringwoodite identified in the low grade ore. The mass magnetic susceptibility of low grade ore is very high 5.2 cm3/g compared to 2.7 cm3/g for high grade ore, due to the presence of abundant quantity of iron bearing minerals. Subsequently, these two types of ore were subjected for magnetic separation for improving Cr:Fe ratio by using different magnetic separators viz. induced roll magnetic separator, wet high intensity magnetic separator, rare earth roll magnetic separator, rare earth drum magnetic separator. The results of magnetic separation studies indicated that, Cr: Fe ratio of the chromite ores can be improved to 3.99 and 1.97 from the feed assaying 3.09 and 1.29 respectively. Studies on rare earth roll magnetic separator indicated that both the ores were upgraded to a maximum Cr:Fe ratio level at optimised condition. Keywords: characterization, QEMSCAN, magnetic separation, rare earth roll magnetic separator, industrial mineral, chromite

Sep 1, 2012

BHP Billiton Olympic Dam produces copper cathode, uranium oxide concentrate and refined gold and silver. The operation is comprised of an underground Mine and Processing Plant and is located 560 km north of Adelaide. Water for the operation is sourced from two wellfields located 120 and 200 km from the operation in the Great Artesian Basin (GAB) at a rate of approximately 36 ML/d. Regulatory drawdown limits were established to protect regional GAB springs and are monitored at compliance bores. Drawdown was predicted in the æOlympic Dam Environmental Impact StudyÆ (Kinhill, 1997); however, pumping at higher volumes may have the potential for increased drawdown resulting in a trend towards the compliance limits. In recent years increased usage of water in the Concentrator and Hydromet sections of the Processing Plant has caused excess process water reporting to the Tailings Retention System (TRS). This has resulted in excessive amounts of liquor ponding on the tailings cells with a potential impact being contamination due to seepage of liquor to groundwater. Effective management of water by the operation is necessary to both reduce GAB drawdown and reduce the amount of liquor on the tailings cells. A site working-group has been established to investigate and pursue opportunities to improve the water use efficiency of the operation. This paper will highlight the issue of water management at Olympic Dam and discuss the various options currently being investigated to improve management of this important resource.

Jan 1, 2006

Originally developed as a step change in ultrafine grinding efficiency, the IsaMill? has made inroads into conventional ball mill and tower mill mainstream grinding duties during the last 5 years - beginning with the Anglo Platinum mainstream grinding projects in South Africa. At the 2006 SAG Conference, plant testwork on the incorporation of IsaMill? technology into the McArthur River (Northern Territory, Australia) Pb/Zn primary grinding circuit was reported. The IsaMill? has now become an integral component of that circuit, treating up to 1mm top size feed and directly producing P80 45 µm rougher flotation feed. Two 1.1 MW IsaMills? are now used in this duty contributing to a 27% increase in overall plant throughput and a reduction in rougher feed size distribution. In this paper, we report on the current state of development and performance of the IsaMill? in the primary grinding duty at McArthur River and also consider future directions.

Jan 1, 2012

By Rick Honaker

Rare earth elements (REEs) contained in coal and associated mineral matter exist in several forms including micro-dispersed minerals, ion adsorption onto clay surfaces, and chemically bound. Tests found that REEs can be effectively recovered from certain components of three coal sources by leaching under mild conditions followed by solvent extraction. A range of pH values were evaluated at solution temperatures of 25 and 75 °C. When using 1.2 M of sulfuric acid, nearly 85% recovery of the REEs was extracted from the middlings material collected from an operating plant. Acid leaching of a second middling source from another plant resulted in 60% of the total REEs being recovered under the same leaching conditions. Solvent extraction treatment of the leachate produced from six different coal sources resulted in products containing up to 50% total REEs from feedstocks starting with around 300 ppm.

By Malcolm Black

Introduction The circumstances under which the gold mining industry was forced to curtail operations a few years ago are well known to all. The effect of those circumstances is particularly noticeable when one enters some of the larger mills that were designed, in better times, to treat relatively large tonnages. On their grinding floors one will observe that a number of grinding units are lying idle, and the ravages of rust are everywhere in evidence. The same applies to other equipment throughout these mills. In 1941, we found it necessary to reduce tonnage considerably in the Wright-Hargreaves mill. With the assumption that a lower tonnage would be of long duration, we began to focus our attention on some of the idle equipment with a view to re-arrangement of the flow-sheet for greater economy of operation. In an article by the writer published in the Engineering and Mining Journal (March, April, and May issues, 1939) , it was pointed out that in designing this mill there was a very limited floor space available. The choice of thickening equipment was imposed solely by the necessity for space: conservation. Thickening by gravity would have required 5,000 square feet of floor space, whereas Genter thickeners required only 1,200 square feet. As a consequence, the Genters were chosen. The decision to add flotation to the circuit was made primarily to save space. On a cost-plus-tail basis, 80 to 100 hours agitation on all pulp would produce similar overall results, but would require much more space.

Jan 1, 1948

By J. H. Gasper

The overall success of steep slope (>20°) contour mining is dependent upon many factors. The major factor is the selection of the mining method that best suits the premining site conditions both environmentally and economically. These conditions can be divided into three major categories: 1) Geometric Conditions --machine limitations, slope stability restrictions, erosion capacity, among others; 2) Physical Conditions--material properties, rock strengths, diggability, driving surfaces, among others; 3) Chemical Conditions --acid/base relationships, blending or selective placement of overburden, among others. This paper incorporates these conditions through conceptually modeling compliance oriented contour mining methods; in particular Haulback methods, utilizing: 1) the Front-End Loader (FEL)/Truck; 2) Tractor Scrapers; and 3) Combined FEL-Truck/Scraper. Engineering analyses including machine selection, sequencing, ease of varying production rates, slope requirements (for stability and running surfaces), drainage requirements and many others can be performed after the geometric constraints dictated by in-situ conditions and regulatory requirements have been conceptualized. Once all generalized geometries have been established, reduction to idealized three-dimensional views is achieved. These are then reduced to two-dimensional symbolic models, mainly plan views, but also elevations and sections. Equipment activities and operations are then conveniently overlayed. Without this simple two-dimensional reduction, technology transfer remains awkward and non-analytical.

Jan 1, 1991

By D E. G Connelly, K Y. Wong

Gold at the Harbour Lights Mine (HLM), WA occurs principally in pyrite (Py) and arsenopyrite (AsPy) minerals rendering it inaccessible to direct cyanidation. Froth flotation produces a concentrate with low mass recovery and with high recoveries of sulfides. After investigating several alternatives, a novel flotation process has been developed to separate the concentrate into pyrite and arsenopyrite rich fractions. The pyrite fraction is finely ground and cyanide leached, while the arsenopyrite is treated off-site. This paper describes the separation process from laboratory bench scale through to commercial operation at the HLM gold plant.

Jan 1, 2005

By R. K. Filip

"Steel bearing piles have long been used to carry high compressive, tensile and lateral loads. Such piles are most commonly tubular or ""H"" profile and are typically installed using percussive techniques. The noise and vibration associated with such installation techniques tends to preclude the use of steel bearing piles in urban and other sensitive areas.This paper describes the design and construction of an innovative new road bridge in Milton Keynes, UK. The steel bearing piles were required to continue out of the ground to form the bridge columns and abutments and then be cast directly into the soffit of the reinforced concrete bridge deck. This project was to be the first time in the UK, that this form of bridge design had been used.The paper shows how new installation techniques allowed the designers to use these high capacity steel elements in a sensitive urban environment without the use of percussive or vibratory installation techniques. Finally the paper shows how these quiet and vibration-less installation techniques can be extended to other applications.A UNIQUE BRIDGE SUPPORTED ON ""BOXED SHEET PILES""CONCEPT HISTORYThere are over 700 bridges in Milton Keynes. Concrete is the dominant construction material, most are single span with massive parallel wing wall retaining abutments. All have a certain uniformity of aesthetic design. Pell Frischmann Consultants Ltd (PFC) proposed to the client, English Partnerships (EP), that an ""integral bridge"" with a slender open appearance would be an appropriate aesthetic form for a new highways bridge, within the district of Westcroft (figure 1). The concept required that the bearing piles be continued up out of the ground to form the bridge columns and abutments. Four rows with four piles in each row were suggested. Each would then be cast directly into the reinforced concrete bridge deck forming a moment connection (figure 2). This concept meant that a single continuous steel structural member would replace traditional reinforced concrete bored piles, pile caps and piers. This member would carry vertical and lateral loads. The conceptual design was intended to meet the following client requirements:"

Jan 1, 2005

By S. Angioletti

This paper addresses strategic investment decisions when they are nested in a project development format where each project is implemented in phases and each phase is approved to move on to the next phase only if certain technical and economic requirements are met. This configuration is sometimes referred to as a ?Project Portfolio?. Mining companies maintain project portfolios in their exploration investment plan. This study proposes a procedure to best manage an exploration project portfolio including technical and economic uncertainties. The procedure may support decision makers in a simple and intuitive way, while maintaining the rigor and precision required by the rather large amount of financial resources typically called for by mining projects. The procedure was tested in a real case study of a gold mining company and its exploration projects portfolio. The procedure uses the following approaches: i) investment valuation methods under technical and market uncertainties based on Option Pricing Model, Real Option Theory and Option Space; ii) portfolio management and Stage Gate®1 method; iii) Monte Carlo simulation.

Jan 1, 2010

By C. Carrasco

"Over the last 30 years the average grade of mined ore bodies has significantly decreased while the proportion of waste removal has in many cases more than doubled. This has been identified as prime reason of a major increase in energy consumption and decrease in productivity across mining operation. Metal coarse preconcentration of ROM feed grades by size rejects low grade gangue/waste material in the size range of 10-100 mm prior to grinding, typically before primary crushing. This relies on propensity of metal to preferentially deport in the fine size fractions after breakage. Metal preconcentration by size has the potential to increase energy efficiency and therefore improve mining productivity on unit of metal basis. Results of an extensive belt cut sampling campaign conducted at a major Australian Au-Cu mine operation show that for some samples between 90% of Au and 80% of Cu is in 40% of the mass at -50 mm fraction. This indicates that low grade coarse material can be removed from the circuit, doubling feed grade at half of the tonnage and therefore improve energy efficiency per unit metal produced. This response, however presents significant variability in the same order as other processing attributes such as impact hardness and flotation recovery. This has led to development of geometallurgical laboratory tests using blast hole chips and drill core facilitating mapping and population of coarse metal preconcentration signatures in long term resources and short term production models. Preferential Cu deportment by size at drilling scale can be recognised, however scales up factors are required to transform laboratory results to production responses. At 50 % of mass the drilling products underestimate the belt cut responses by 20-30 %. Bulk sampling campaign with blast hole and drill core samples spatially related was also conducted to investigate in more detail the difference between production scale and drilling scale preconcentration responses."

Jan 1, 2014