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By X. Zhou

In this study, the cyclonic static microbubble flotation column (FCSMC) was investigated for fluorite beneficiation. The structure and principle of the specially designed column are described. Fluorite samples from the tungsten separation tailings of the Shizhuyuan Mine, Chenzhou, Hunan Province, P.R. China, were tested using a small-scale continuous flotation test unit, and concentrates with a fluorite grade higher than 98% were obtained. One rougher and three cleaner stages in the FCSMC achieved the same separation performance as one rougher and eight cleaners in conventional flotation cells. This greatly simplified the flotation circuit and reduced operating costs.

Jan 1, 2007

By Serge Ouellet

Identification and quantification of cementitious phases in cemented paste backfill (CPB) is difficult due to the fineness of tailings and the low binder content used in the mixture. Techniques such as X-ray diffraction and thermogravimetry were ineffective (mainly due to tailing mineral interference) to identify and quantify hydration products in most works reported in the literature. On the other hand, scanning electron microscopy (SEM) was used in many cases but mainly for qualitative purposes. This paper presents the development of a new approach based on a computer program (SEM-XMAP) that combines X-ray dot mapping images acquired by SEM and generates a coloured image representing the mineralogy and the microstructure of a given CPB specimen. The technique is applied to one CPB sample mixed with blast furnace slag (BFS) and acidic sulphated mixing water sampled in a mine dewatering system. The technique allowed identifying calcic matrix, unhydrated and partially hydrated BFS particles, and sulphated phases.

May 1, 2007

Hydrogen and carbon monoxide reduction data were obtained on pelletized materials of the type currently being prepared commercially in Australia.Pellets, approximately 1 cm diameter, made from Deepdale, Iron Prince, and Mt. Newman iron ore were reduced by hydrogen over the temperature range 500°-900°C and the reduced pellets were examined by thermogravimetric, microscopic, electron probe, and x-ray techniques. After an initial time delay it was found that up to 95 per cent reduction the data could be described by a porous model where gaseous diffusion through the solid is rate controlling. Independent measurements of effective diffusivity supported the values obtained from the reduction data. Above 95 per cent reduction the rate decreased markedly due to the formation of retained wustite or fayalite.Comparison with reduction by carbon monoxide over the temperature range 750°-900°C showed that the rate of reduction was approximately five times slower than for reduction by hydrogen.The rate of reduction was found to be a function of the initial properties of the pellets which may account for the widely conflicting results that have been obtained with previous investigations on porous pellets.

Jan 1, 1971

By H G. Bosmare, G Bedser, C V. B Cunningham

Peak Quany has achieved substantial improvements to its bottom lie by giving close attention to blasting practice, and in pr@icnlar by introducing electronic delay detonators for routine production blasting. The precision and flexibility provided by these units has enabled the quarry to gain control over fmes and curtail oversize without increasing explosive usage. In addition, the extent of nuisance from blasting vibrations has been reduced.

Jan 1, 1998

By Gábor Csicsovszki

We have developed a novel method - at the laboratory scale - comprising an ion-exchange separation and a membrane-electrolysis step for the purpose of zero-waste regeneration of spent HCl pickling liquors originating from hot-dip galvanizing of common steels. It is aimed at the parallel regeneration of HCl and iron. Experiments revealed that iron can be electrodeposited at high current efficiencies by maintaining the following conditions: 0.04-0.08 M HCl, 500-1000 A/m2, 20°C and stationary electrolyte in a conventional cell. Zinc in the solution did not disturb the deposition of iron, however it contaminated the product and it poisons the anion-exchange membrane required to tackle acidity during electrolysis. For a preliminary separation, anion-exchange tests were carried out to produce pure iron solutions. Beyond the equilibrium studies, column experiments were carried out showing that low flow rates of the loading solution and the ~1.5 M HCl eluent are essential for separation.

Jan 1, 2006

By Mahmut Altiner

This study aimed to produce magnesium oxide (MgO) particles with different properties from dolomite ore using an experimental procedure comprising four stages: sample preparation (S1), HCl leaching (S2), precipitation (S3), and calcination (S4). Three different base sources (NaOH, KOH, and NH4OH) were used as precipitant in the third stage to obtain magnesium hydroxide [Mg(OH)2] from a leachate solution, which was obtained in the second stage. Next, Mg(OH)2 particles generated by different alkali sources were calcined at various temperatures from 600–1000 °C for different durations (1–5 h). The effect of these base types on the properties of each product was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), atomic force microscopy (AFM), and wet chemical analyses. The experimental results indicated that each product was identified as periclase (MgO) mineral, which was produced with a specific surface area (SSA) of 4.49–44.54 m2 /g depending on the production conditions. The surface roughness of the MgO particles increased with increasing calcination temperature. SEM analyses showed that MgO particles produced at a temperature of 600 or 800 °C were amorphous, indicating that the process was not influenced by the base type, but MgO crystals were smooth when the calcination temperature was 1000 °C. Finally, it was determined from all experimental findings that MgO particles produced via the addition of NaOH have superior properties (such as higher SSA and lower surface roughness) compared with MgO particles produced with KOH or NH4OH as the alkali source. These properties led to great improvement of its usability in industry.

By Mahmut Altiner

This study aimed to produce magnesium oxide (MgO) particles with different properties from dolomite ore using an experimental procedure comprising four stages: sample preparation (S1), HCl leaching (S2), precipitation (S3), and calcination (S4). Three different base sources (NaOH, KOH, and NH4OH) were used as precipitant in the third stage to obtain magnesium hydroxide [Mg(OH)2] from a leachate solution, which was obtained in the second stage. Next, Mg(OH)2 particles generated by different alkali sources were calcined at various temperatures from 600–1000 °C for different durations (1–5 h). The effect of these base types on the properties of each product was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), atomic force microscopy (AFM), and wet chemical analyses. The experimental results indicated that each product was identified as periclase (MgO) mineral, which was produced with a specific surface area (SSA) of 4.49–44.54 m2 /g depending on the production conditions. The surface roughness of the MgO particles increased with increasing calcination temperature. SEM analyses showed that MgO particles produced at a temperature of 600 or 800 °C were amorphous, indicating that the process was not influenced by the base type, but MgO crystals were smooth when the calcination temperature was 1000 °C. Finally, it was determined from all experimental findings that MgO particles produced via the addition of NaOH have superior properties (such as higher SSA and lower surface roughness) compared with MgO particles produced with KOH or NH4OH as the alkali source. These properties led to great improvement of its usability in industry.

South Africa?s primary electricity supplier, Eskom, provides incentives to reduce power demand during critical times by granting capital through a Demand Side Management programme. DSM encourages the end user to review and optimize energy consuming systems and use capital, provided by Eskom, to purchase or modify the equipment required to achieve a load-shift. As part of the DSM agreement the mine ultimately acquires the capital equipment and benefits from reduced power costs, but in return is required to sustain the load-shift tactic for up to five years. The paper focuses on one DSM tactic, main fan energy management. In this case, reduced air flows during selected peak and off peak periods, results in a substantial reduction in peak power demand. DSM incentives provided capital for automated main fan control as well as improved control of the mine ventilation systems. To examine the work in detail Gold Fields Ltd Driefontein gold mine near Johannesburg was chosen as a case study.

Jan 1, 2009

By Mark Van Dyke, Ted Klemetti, Joe Wickline

"The identification and mitigation of adverse geologic conditions are critical to the safety and productivity of underground coal mining operations. To anticipate and mitigate adverse geologic conditions, a formal method to evaluate geotechnical factors must be established. Each mine is unique and has its own separate approach for defining what an adverse geological condition consists of. The collection of geologic data is a first critical step to creating a geological database to map these hazards efficiently and effectively. Many considerations must be taken into account, such as lithology of immediate roof and floor strata, seam height, gas and oil wells, faults, depressions in the mine floor (water) and increases in floor elevation (gas), overburden, streams and horizontal stress directions, amongst many other factors.Once geologic data is collected, it can be refined and integrated into a database that can be used to develop maps showing the trend, orientation, and extent of the adverse geological conditions. This information, delivered in a timely manner, allows mining personnel to be proactive in mine planning and support implementations, ultimately reducing the impacts of these features. This paper covers geologic exploratory methods, data organization, and the value of collecting and interpreting geologic information in coal mines to enhance safety and production.The implementation of the methods described above have been proven effective in predicting and mitigating adverse geologic conditions in underground coal mining. Consistent re-evaluation of data collection methods, geologic interpretations, mapping procedures, and communication techniques ensures continuous improvement in the accuracy of predictions and mitigation of adverse geologic conditions. Providing a concise record of the work previously done to track geologic conditions at a mine will allow for the smoothest transition during employee turnover and transitions. With refinements and standardization of data collection methods, such as those described in this paper, along with improvement in technology, the evaluation of adverse geologic conditions will evolve and continue to improve the safety and productivity of underground coal mining."

Jan 1, 2019

By Raymond Philippe

Background ?Hatch Water has worked with most major mining companies in Chile on water supply and optimization projects ?Many(copper) mining projects are located in Northern Chile, which hosts the driest desert on earth Water supply options in Northern Chile ?River ?Availability/Rights ?Well(Brackish) Water ?Availability/Rights ?Municipal Wastewater ?Water rights ?Volume ?(Desalinated) Seawater ?Infinite source ?Cost depends on distance and altitude ?Recycling/Reutilization ?Water losses All these options present water quality issues

May 1, 2009

By T Higuchi, L Lu

The quality of iron ore fines have been deteriorating, which has affected sinter quality and productivity adversely. New pretreatment and sintering technologies are therefore required to tackle the gradual change in the quality of iron ore fines. In the sintering process, iron ore fines are first granulated with fluxes such as limestone and coke breeze, and are then loaded and fired in a sinter machine. Sinter productivity and quality are heavily influenced by the reactions occurring in the sintering bed. Hence fundamental understanding of these high temperature properties of ores is urgently needed.Formation of initial sinter melt, penetration and assimilation of nucleus particles by the initial melt, and consolidation and final solidification of final sinter melt are believed to be the key sintering reactions. The assimilation and penetration phenomena have been studied separately in the literature with model particles and diffusion couples and are therefore difficult to relate to sinter quality. In addition, the effect of ore mineralogy has not been studied in detail.In this study, tablets consisting of coarse particles from various iron ore fines as nucleus particles and chemical reagents as adhering fines were made and fired under various sintering conditions to investigate the penetration and assimilation behaviour simultaneously. The degree of assimilation, pore structure, compressive strength of the resultant analogue sinters were evaluated and the relationship between sinter strength and ore characteristics was further discussed. The nucleus particles from Ores A and B were found to be more porous and assimilated more readily with sinter melt, resulting in a viscous melt and a macro-porous sinter structure. The nucleus particles from Ores C and D on the other hand, assimilated less readily with sinter melt, resulting in a fluid melt and a denser sinter structure. This is consistent with the results reported in the literature, suggesting that the present evaluation method can be utilised for studying sintering reactions and predicting sinter quality.CITATION:Higuchi, T and Lu, L, 2017. Evaluation of sintering behaviour based on ore characteristics, in Proceedings Iron Ore 2017, pp 303–308 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By Jonathan Allen, Peter Radziszewski

"Stirred mill technology dates back to 1928 where the idea to use “an agitator and spherical grinding media” was presented. The year 1948 saw the successful application of DuPont’s “sand mill” for pigment grinding. Subsequent years have led to the development of different types of stirred mills spanning a number of industries that require fine and ultrafine grinding. In the context of the mining industry, smaller grain size and other mineralogical characteristics have motivated the need to grind finer. In order to address this need, the interest in stirred milling technologies has grown over the last 20 years as can be illustrated by the large body of literature published over this same period of time. The typical observation reported in the literature is that in certain circumstances stirred milling is significantly more efficient than ball milling. Despite these developments, the tumbling mills are continuing to be used in fine and ultrafine grinding applications. The main reason for this, as communicated at the Canadian Mineral Processors roundtable discussion in 2013, is that the comfort level in understanding stirred milling technologies is not at the level of that of tumbling mills. The aim of this paper is to contribute to increasing the general comfort level with stirred milling technologies by developing a better understanding of how power and energy is affected by stirred mill impellor design and mill operation. This will be accomplished by first completing an overview of the power models found in the literature followed by a general description of DEM and CFD stirred mill models as well as the insights that can be drawn from them. Finally, a generic stirred mill power model will be presented and applied to different stirred mill types in order to develop some insights into the differences between different mill types. The paper will close with a discussion on some of the challenges that these models have and how future research might contribute to overcoming them."

Jan 1, 2014

An assessment of methods currently available for the accurate determination of low concentrations of platinum in ores and mineral concentrates indicated that prior treatment of the sample by fire assay procedures is necessary. To enable rapid determinations to be carried out, instrumental methods applied to the metallic bead produced from the fire assay treatment have been evaluated, considering maximum flexibility for concentration variations, minimum chemical operations, and adequate sensitivity.Atomic absorption spectrometry proved suitable, giving solution determination limits of 0·4 p.p.m. Pt, 0·1 p.p.m. Pt, or 0·06 p.p.m. Pt under various extraction conditions using aqueous and organic agents. Thesedetermination limits related to 1 assay ton of sample (32·67 g) produced easily readable and accurate readings within the range of platinum contents (0·03-2·0 p.p.m.) of economic interest in deposit evaluation and prospecting. The technique shows promise of also being suitable for determination of palladium and gold.

Jan 1, 1970

By M. A. Trevits

The National Institute for Occupational Safety and Health (NIOSH), in partnership with the Mine Safety and Health Administration (MSHA), is conducting research to test, evaluate, improve or modify coal mine fire-fighting strategies and methodologies through large-scale tests. Since wood is the second most abundant fuel available during a coal mine fire, it was decided that series of large-scale wood crib fire tests were needed to measure the products of combustion and to observe the capability of commonly available direct application fire suppression equipment, namely, fire extinguishers, water and gas-enhanced foam. This paper discusses the wood crib fire tests, provides insight into the products of combustion and describes observations made during the application of the fire suppression agents.

Jan 1, 2009

By W. J. González

"With the increasing demand for minerals, technologies to maximize mineral recovery are paramount to a mine’s economic success. Many mining process waters have the potential to form calcium-based inorganic scales, which inhibit effective mineral recovery. Often, the solution to inhibit these deposits is the implementation of a chemical antiscalant program. This paper examines the application of a fouling analyzer to continuously monitor the formation of inorganic scale in mining process streams. The fouling data can be used to compare antiscalant programs and to optimize antiscalant feedrates. Case studies validate the ability of this technology to help optimize mineral recovery processes.INTRODUCTION The mining industry uses significant quantities of water. From quarrying, to crushing, to flotation, leaching, and refining, water is often the integral motive force to move slurries, separate or agglomerate fines, and extract and purify minerals. As well, water is used in a number of ancillary applications at mines, including dust suppression, gas scrubbing, and utility processes such as boiler, cooling, and waste water operations. For many processes, the quality of water being used is inconsequential. However, for certain processes, such as flotation, leaching, and desorption / stripping, water quality plays a key role in the ability of the operation to economically recover the target minerals. Dissolved solids such as calcium and magnesium salts can concentrate in process waters, exceed their solubility limits, and precipitate as scale on metal surfaces such as feed and transfer pumps, piping, and equipment. Some of the more common scales that form in mining operations include calcium carbonate (CaCO3, or calcite) and calcium sulfate (CaSO4, or gypsum), and to a lesser extent, calcium and magnesium silicate compounds. Any scale that deposits in a process stream will negatively impact mineral recovery, and increase the operational costs of the mine site. Whether it is acid washing a scaled heat exchanger in a carbon strip at a gold operation, replacing plugged emitter tubes in a leaching operation, or hydroblasting process lines in a scrubber unit, there are costs associated with labor, cleaning chemicals, repairs, and replacement parts. These costs pale in comparison to the potential costs of downtime and lost production, should the scale deposits occur in a process that is critical to the recovery of the target mineral."

Jan 1, 2014

By P. J. Yttrup

Small diameter timber piles are used in Australia to solve foundation problems in soft or filled ground and expansive soil. The paper describes the results of pile load tests to develop simple methods for bearing capacity determination and observation of the performance of piles in expansive soil.

Jan 1, 1989

By J. A. Elliot

Deep Mix-in-Place soil stabilisation is achieved by forming columns of soil/cement arranged to overlap by secant intersection. Alternate columns are constructed initially and infilled. The cementitious material injected is designed to retard the strength of the resulting mix thereby allowing satisfactory overlapping. Columns are constructed using a designed large diameter mixing auger mounted on a smaller diameter auger stem. This is firstly screwed to the design depth removing only such spoil as to enable penetration of the auger, and subsequently counter rotated and extracted in a predetermined mixing pattern and grout injection rate to ensure continuous and homogeneous treatment through each successive level. The process is performed whilst monitoring auger depth, grout flow and pressure. Cementation Piling and Foundations Limited used this technique to stabilise allu­vium and to facilitate the construction, by conventional techniques, of a circular pumping station pit of 10M diameter to 10M below ground level. The work was carried out within 3M of adjacent domestic properties, and on a very restricted site in Elland, West Yorkshire. Ground conditions consist of 2M of cohesive alluvium becoming water bearing and increasingly sandy and gravelly with cobbles which overlies the mudstones at 10.0m depth. Sandstones beneath formed an aquiclude to artesian ground water with the underside of the open excavation approxi­mately 1.0M from the top of this material. Peripheral treatment into the mudstone, coupled with pressure relief wells, proved successful and final excavation depth was achieved in "the dry".

Jan 1, 1989

By Green P. F

Apatite Fission Track Analysis (AFTA) is a thermal history reconstruction tool that enables determination of magnitude and timing of maximum paleotemperature and paleo-geothermal gradient at the time of maximum paleotemperatures. From this information, the amount of section missing at major unconfornities can be estimated and incorporated into basin models. The Gippsland Basin has a number of distinct problems that can be tackled using AFTA. 1. The nature of the regional break between the Late Cretaceous-Tertiary Latrobe Group and the underlying Early Cretaceous Strzelecki Group. 2. The tectonic history of the basement flanking the basin and its effect on sediment composition. 3. The age of igneous activity in the basin, as typified by the widespread basaltic plugs and dykes intruding the outcropping Strzelecki Group. Major uplift and erosion within, and adjacent to, the early Cretaceous rift basin in the Mid-Cretaceous, at -95 to 100 Ma, initially constrained the Latrobe Group depositional area to the central deep of the Gippsland Basin and provided an elevated source of quartz-rich detritus for the Latrobe Group reservoirs. This is in marked contrast to the preceding period in the early Cretaceous when contemporaneous volcanism dominated as a source of detritus, producing quartz-poor lithic sandstones, in which a host of attendant diagenetic reactions destroyed their reservoir potential. Initial uplift and erosion of the volcanogenic Strzelecki Group also occurred in the mid-Cretaceous as revealed by a number of distinct inversion structures, and erosion of this material will have locally provided very poor quality sand to the basal Latrobe Group.

Jan 1, 1992

By Derrick D. Dasenbrock

Three piers of a new river bridge are supported on 1.067 m diameter open-end steel pipe piles. At time of drive, and after pile re-strikes, high-strain dynamic capacity values at plan tip elevations, were as low as 23% of design requirements. Pile lengths were extended 20% to 40% deeper than planned at two piers, driving to rock, impacting both the project cost and schedule. The significant discrepancy between predicted and observed capacity was investigated through a series of coordinated dynamic tests; a full-scale test pile was installed and monitored over 221 days by both dynamic and quasi-static methods. Unusually slow strength gains were observed by dynamic monitoring on all piles installed at the site. CPT soundings were advanced at the test pile and through the pile interior to investigate the soil plug. High-strain dynamic methods were found to have significant limitations in properly assessing the long-term capacity of large-diameter open-end pipe piles during driving and short-term pile re-strikes. As the benefits of large diameter high-capacity open-end pipe piles are numerous, the geotechnical community needs to address appropriate construction monitoring and control of these foundation types to take full advantage of these systems. An improved understanding of the physical effects of pile installation and the impact on soil strength assessment while driving and long term soil strength gain should be developed and incorporated into both design and monitoring procedures to avoid either unsafe or needlessly costly designs.

Jan 1, 2006

By R. Schulz, K. King

Concentrating Line 6 just went down again. The control room operator checks the graphic display. Only one piece of equipment shows an alarm. Clicking on the ball mill icon, he discovers the culprit was the low flow lube switch. The flow looks okay now, but it is the third time this week the switch has stopped the line. Maintenance is called, the switch replaced and the line is up running again. Sending the right person to the right spot immediately can save hundreds of hours of downtime every year. This paper discusses the principles behind implementing smart First-Out Fault Detection to dramatically reduce equipment downtime in new, or existing control system architectures. Methodologies are presented to maximize the system benefits, while minimizing development costs. Case histories are presented for a number of successful implementations in mineral processing plants.

Jan 1, 2001