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By T Kojovic, S J. Windle, J Sullivan

"The Geometallurgical Mapping and Mine Modelling (GeM) comminution index (CI) was developed as part of the AMIRA P843 GeMIII project. Drill core geochemistry samples were passed through a Boyd Crusher with standardised settings and the resulting particle size distribution (PSD) was measured using sieves.Disadvantages of the original measurement were the relatively coarse crush size, requiring a second pass of crushing for geochemical sample preparation, and the limitation of throughput caused by the sieving step. At Antamina, the measurement has been modified to use a 2.2 mm crusher size setting, which permits a single pass. The PSD is measured using a Camsizer, an automated optical sizing instrument. The Camsizer sample is a +180 µm fraction, used to avoid passing too many fines through the instrument and slowing down the measurement. In the sieving step, the weights of the two fractions are recorded and subsequently used to normalise the distribution measured by the Camsizer. In this way, the throughput of the Camsizer can match that of the Boyd Crusher. The PSD data are therefore measured without penalising the throughput of the sample laboratory.The normalised PSD distributions are used to derive modified CI parameters, based on the slope and intercept of the breakage product size distribution, which are indirect measures of the material breakage hardness.Fifty samples were selected as a training set, each sample a composite of five or six individual assay intervals and each with its own measured CI. The average PSDs were calculated for the composites and used to calculate a composite CI. The intact half of the core, approximately 40 kg, was tested to measure the BWi, A*b and crushability. The results were used to develop predictive algorithms for these hardness parameters.A further 50 composites were chosen for lab testing, to serve as a blind test of the algorithms. The paper reports on the test results and the incorporation of the modified CI data and predicted hardness parameters into the Antamina block model.CITATION:Windle, S J, Kojovic, T and Sullivan, J, 2016. Use of a Modified Comminution Index to Predict Bond Work Index and SMC A*b at the Antamina Mine, Peru, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 153–160 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By A L. de Ambrosis, F M. Weir, M Fowler

Traditional kinematic and statistical analyses of geological structure for geotechnical engineering applications, while considered industry standard practice, have some limitations and unrealistic assumptions. An improved approach involves a discrete fracture network (DFN), a numerical model that explicitly represents how defects may be spatially distributed through the rock mass. The DFN technique utilises the structural data in stochastic analyses to give a range of possible models used for visualisation and stability analyses.The early development of the DFN approach was largely associated with modelling fractured hydrocarbon reservoirs and nuclear waste isolation programs. With recent improvements to computational power it has become recognised internationally as a valuable tool for modelling some geomechanical problems encountered when designing excavations in fractured rock masses. For tunnelling or slope stability projects DFN modelling provides visualisation of a rock mass and identification of likely failure mechanisms.This paper presents a suite of DFN modelling undertaken for the design of a tunnel within the Ashfield Shale unit of the Sydney Basin, Australia. The necessary input parameters and derivation of these, along with the importance of both an accurate engineering geology model and validation of the synthetic fracture network are demonstrated. Multiple realisations of the DFN were analysed to provide an indication of the number and volume of unstable blocks for the proposed tunnel geometry, enhancing support design. One fracture network realisation was sliced along multiple sections for use in finite element modelling.CITATION:Weir, F M, de Ambrosis, A L and Fowler, M, 2014. Discrete fracture network modelling for tunnel design in the Sydney Basin, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 219–226 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By Wm. L. Giachino

"Over the last 10 years, C-1-L has played a significant role in the major advances that have taken place in blasting technology, among them the following: development and introduction of capsensitive slurries; development of bulk slurry systems both for underground and open-pit operations; development of the TOE-DET and ANODET systems of delay blasting;introduction of the NONEL system of initiation;development of the Vertical Crater Retreat (VCR) system of mining.This paper identifies areasin which we foresee further developments in blasting technology over the next 10 years and outlines how and to what extent C-1-L will become involved."

Jan 1, 1980

By G. M. Wilemon

The U.S. Bureau of Mines has conducted investigations on extracting phosphate values from wastes generated during the mining and beneficiation of phosphate matrix. These wastes may contain up to one third of the phosphate originally present in untreated ore. Samples of wastes were air-dried and leached using 93 pct sulfuric acid in the presence of methanol. Evidence for the formation of a calcium sulfate hemihydrate coating that hinders complete dissolution of phosphate is presented. Solid-liquid separations were enhanced when flocculation was effected using poly(ethylene oxide) (PEO) in conjunction with hydroxypropyl cellulose (HPC) or hydroxyethyl cellulose (HEC. A conceptual flowsheet for a proposed process using an acid-alcohol leaching technique is presented.

Jan 1, 1990

By E. Hasanbas

Vibrating screens and crushers are the workhorses of material sizing. Unfortunately their natural frequency is often in the range of typical supporting structures, thereby making installations prone to vibration problems. Much of the available literature regarding the support of vibrating screens is fairly confusing and outdated. This paper presents the results of utilizing accelerometers and finite element software in the analysis and design of supports for vibrating equipment. It contains data from field studies of vibrating screen and crusher installations, design of new and repair of existing supporting structures, and the correlation between field data and finite element time history analyses. Finally, the paper summarizes a method for analyzing and designing structures subjected to vibratory loads and predicting their behavior.

Feb 23, 2014

By Frank F. Aplan

In looking into the crystal-ball scene of minerals beneficiation for 1970 and beyond, an impartial observer becomes con- fused as to what has been done and what is possible in the way of improvements. The mining official must balance the burden which is being shouldered by the mineral industry for maintaining our environment in its pristine state on one hand, with the solid advancements made in technology and cost savings on the other hand. Then the official wonders if this is really the criterion for judging overall performance today. As a prospective engineer, Dave Bolles sees it this way: "Specialization has caused many engineers to subordinate everything to doing their job the cheapest and fastest way. In the future this won't be enough. The engineer in the mineral industry will be responsible not only for mining, concentrating and smelting, but also for the resultant wastes- the mine dumps, the tailing dams and the slag piles." (See Drift on page 63).

Jan 1, 1971

By S. Klein, M. McLeod, S. Gambino, K. Johnson, E. O’Hara

The Mokelumne Aqueducts Resiliency Project (MARP) involves construction of a 16.5-mile tunnel across the Sacramento-San Joaquin Delta (Delta) to replace the existing surface aqueduct pipelines with more resilient conveyance. The tunnel will be bored in Pleistocene-age alluvium at elevations between 100 to 10 feet below mean sea level. At this depth ground conditions are signicantly stiffer and denser than surcial soils and will mitigate potential seismic harards related to liquefaction ground shaking and cooding that could arise from potentially damaged levees. The heterogeneous soil deposits at tunnel depth consist of interbedded layers of stiff to very stiff clay and silt, and dense to very dense clean sand and silty sand.

Jun 23, 2024

By Z Tong, M Gao, X Wang

In response to the need for improved magnetic separators for beneficiation of fine grained iron ores that have been finely ground to liberate the iron minerals from the gangue, a series of high efficiency wet drum permanent magnetic separators (T-GCT) has been developed by Maanshan Tiangong Technology Co Ltd. These magnetic separators have high efficiency for separating superfine strongly magnetic minerals and the ability to produce high-grade concentrates with high recovery. They are ideal replacements for conventional drum magnetic separators, especially for treating superfine particles.

Jan 1, 2009

By Tim Lundquist

Disa Technologies Inc. provides innovative, sustainable solutions for mineral processing and remediation through its patented High-Pressure Slurry Ablation (HPSA) technology. HPSA processes solid feed material in slurry form, propelled by high pressure pumps through opposing nozzles that generate impinging jets within a collision housing. This process induces particle-to-particle collisions in a high energy zone, creating intergranular fractures along grain boundaries. In our batch scale and continuous operating testing, we have found that controlling key processing variables such as nozzle velocity, slurry solids percentage, and the number of passes can allow for controlled size reduction and maximum mineral liberation. Since 2018, Disa Technologies has demonstrated the versatility of HPSA by testing it on diverse materials, including phosphate, copper, uranium, vanadium, zinc, rare earth elements, lithium, nickel, mineral sands, gold tailings, and more. The intent of this paper is to present an overview of our test results describing in detail impacts on size reduction, recovery, and grade with a focus on HPSA's adaptability across ore types. Looking forward, it explores the potential to process materials such as DR-grade iron, clay, PGMs, bauxite, and various tailings. Additionally, it examines planned advancements in HPSA technology, including optimized nozzle spacing, higher capacity models, improved tonnage-to-footprint ratios, enhanced maintenance features, and expanded nozzle configurations.

Jan 1, 2025

By Rajasekar Subbian, Jessica Oudhof

In the Netherlands pile foundation design is done using CPTs in accordance with EC7 national annexure. The capacity per tip level is calculated for every CPT followed by zonation to find the tip level per zone. The correlation factors are used to take into account the variability in ground across the zone and they depend upon the number CPTs within the zone. The CPTs and pile tip levels selection for zoning is an iterative process that can demand significant manual effort to produce an economical pile plan. This often leads to the use of conservative correlation factors in order to accelerate the design process. Thus, it has been automated in a tool with CPTs, pile location and loads, and capacities as input. The tool has also been employed in two case studies and the results are compared to the current design practise.

May 1, 2022

By Ross. C. Barkley

A computer program has been written to simulate ground vibrations induced by multiple-hole surface blasts. The program is an inexpensive and relatively easy to use tool for predicting the principal blast vibration characteristics that determine damage and annoyance potential: peak particle velocity, frequency content and pulse duration. The program generates a complete ground motion history by superposing, at any surface position, the vibrations induced by each individual explosives charge. It requires specification of (hence allows accounting for) the blast geometry, initiation sequence (including random delays), position with respect to blast, pulse characteristics induced by each charge, and propagation laws. A methodology is outlined to determine the necessary variables either on the basis of site investigations (e.g. velocity, attenuation, pulse), or by backcalculation from measured blast vibration records. The latter procedure has been applied to blasts from two coal strip mines. Main difficulties are backcalculating individual pulses, propagation (especially dispersion) parameters and delays. A normal distribution of delays, based on published results, has been shown to influence the results and the response of a single degree of freedom structure significantly. Broadening of the wave types included and additional verifications with field results are required.

Jan 1, 1983

By P. Malíková, I. Osičková, R. Sousedíková, P. Rys, J. Dvořáček, S. Heviánková

Each mining project goes through the same life-cycle, from prospecting and exploration to closure and post-closure periods. This prompts the question whether the closure of a mine constitutes the end of its life-cycle or whether the decommissioned mine can be employed for some other purpose. Best-practice references indicate that there are many viable options. In our opinion, the production of service water is one such option. Laboratory research was carried out on the water from a flooded underground coal mine in Ostrava- Karviná coal district, Czech Republic, concerning the production of service water from pumped minewater. The research proved the practical feasibility of service or process water production. Given the effect of global climate change with regard to water resources, good prospects for this additional resource can be assumed since the water has to be pumped in any case for safety reasons.

Oct 1, 2022

By Chee Theng

"Mineral processors know you can put in the best technology in the world but it won’t work optimally without the support of the operators. Conversely, you may have complete operator support but won’t get top results without the right technology. When the two come together, the returns can be phenomenal.The first day of talks at the 68th Annual Colorado MPD Conference, held April 26-28 at The Broadmoor in Colorado Springs, covered the ground on these industry wisdoms.Coming together as a team“Think of the people, not just the lab and the numbers. That makes all the difference,” said Dee Kippers, of FMI Henderson Mine, in her talk on “Process optimization during a market downturn (A Moly MacGyver story).” Kippers told an entertaining story of the journey she and her team took in tackling the issue of an annual spike in iron content in the product at Freeport- McMoRan’s Henderson primary molybdenum mine near Empire, CO.As the metallurgists tried one thing after another — cranking up the iron depressant, adjusting pH with sodium hydroxide and hydrated lime, modifying reagent levels — Kippers found that when she shared her results with the operators, communicated with them on what she was doing and got their input, they were more willing to work with her, and more understanding and supportive of her efforts.The results make the case for getting people on board and coming together as a team. The cost savings from their optimization efforts, with little capital investment, have been “enough to cover the annual salaries of our metallurgy department and then some,” Kippers said.Considering the environmentDavid Lemieux, of Dundee Sustainable Technologies (DST), talked next on “Cyanidefree process for gold extraction,” presenting the results obtained from a demonstration campaign of the company’s novel chlorination process for gold extraction and associated arsenic stabilization process. Developed at an investment cost of C$35 million, they are ready for commercialization, having been demonstrated on the laboratory, pilot and demonstration scales.The DST process is differentiated from the Plattner chlorination process, which was in use from 1851 to 1916, by moderate process conditions of atmospheric pressure and ambient temperature — the result of using sodium hypochlorite solution, or bleach, instead of direct injection of chlorine gas — and new, cheaper materials of construction, such as polymers, plastics, fiberreinforced plastics and Teflon, resulting in lower capital and operating expenditures."

Jan 7, 2018

By G. Y. Liu

The structure-activity relationships for four thionocarbamate collectors are discussed in this pa-per. These collector classes are alkyl alkyl thionocarbamates, allyl alkyl thionocarbamates, acyl al-kyl thionocarbamates and alkoxylcarbonyl alkyl thionocarbamates. The main emphasis will be to highlight the differences between collectors and their affinities for copper and iron sulfide minerals on the basis of data on electronic-structure properties obtained by vacuum and solution density functional calculations, flotation experiments and analysis measurements. The mechanism of interaction of these collectors with sulfide minerals is also discussed with perturbation theory. The theoretical study results indicate that acyl alkyl thionocarbamates and alkoxylcarbonyl alkyl thionocarbamates have best performance in these agents as flotation collectors with improved collecting power for copper sulfide minerals and excellent selectivity against iron sulfide minerals, which are consistent with the experimental data reported in the literature.

Jan 1, 2014

By Josh Willhite, Seth Pollak, Ben Seling

The Long Baseline Neutrino Facility Far Site at the Sanford Underground Research Facility in Lead, South Dakota will house four large detector tanks located in deep underground caverns. Construction of the supporting infrastructure required for this project is no complete including installation of a waste rock conveyance system and drill and blast excavation of several supporting drifts and chambers. This paper will discuss the design and construction of these pre-excavation and early works elements, and the overall project schedule as it closes in on commencement of cavern excavation activities.

Jun 13, 2021

By Amélia de Santana Cartaxo

Este trabalho tem como objetivo o estudo de matérias-primas utilizadas nas indústrias de cerâmica vermelha da Região do Cariri-Ce, de forma a adequar o processamento às especificações de composição, umidade e temperatura para obtenção de componentes com qualidade e características satisfatórias. Para tal, foi realizada a análise de composição através de FRX, limites de Atterberg, retração linear, absorção de água e tensão de ruptura à flexão, pós queima, em três temperaturas distintas. Pode-se observar que algumas argilas apresentaram composições típicas das utilizadas para a fabricação de produtos da cerâmica vermelha, aumento de tensão de ruptura e retração com a temperatura de queima, redução da absorção com o aumento da temperatura de queima e a penas as amostras AM e BP encontraram-se no intervalo de extrusão satisfatória.

Aug 17, 2017

By W. A. Gow, J. A. Vezina

"A new process for treating scheelite for the production of tungstic tri-oxide is described. The novelty of the process resides in that an ion-ex-changer is used to convert sodium tungstate to either ammonium tung-state or tungstic acid.The process consists of a conventional hydrochloric acid leach of the scheelite concentrate, and the dissolution of the impure tungstic acid thus produced with sodium hydroxide at pH 8. The sodium tungstate solution is clarified and passed through a column of Dowex 50Wx8 ion-ex-change resin to exchange the sodium ions for either hydrogen or ammonium ions, both being suitable. The tungsten-bearing column effluent is evaporated to crystallize the tungsten as ammonium tungstate; the crystals are washed with nitric acid and water and decomposed by heat to pro-duce tungstic trioxide of high purity.Ninety-six per cent of the tungsten in the concentrate may be re-covered as tungs tic trioxide (W03), and the reagents consumed are 0.7 g HCl, 0.41 g NaOH and either 1.73 g NH.Cl or 225 g HCl per gram of tungsten."

Jan 1, 1966

By Nadir Ansari, Brian W. Wilson, Marina S. W. Li

"A hybrid Deep Mixing (DM) shoring system was recently constructed for a high-rise development in downtown Vancouver, British Columbia, Canada for the temporary support of a five-level basement excavation. The site is bounded by an existing bridge off-ramp structure along its longest side and by city streets on the other two sides, which formed a truncated triangle in plan. A conventional secant pile wall was installed along the longest side, about 380 ft (116 m) in length, of the site. Hybrid shoring walls (HSW) 1 and 2 were installed along two shorter sides with each being 235 to 246 ft (72 to 75 m) long. HSW 3 completed the excavation support system along the shortest side with a length of about 55 ft (17 m). Cutter soil mixing (CSM) was proposed by the excavation and shoring design-build team in lieu of conventional secant piling. CSM was the preferred method to construct the infill panels between soldier piles because of the speed at which the shoring system could be constructed in the variable fill, peat, wood waste and overburden. Design ConsiderationsTo minimize the impact on buried utilities along the outside perimeter of the excavation, the temporary shoring was designed to limit the lateral displacements to less than 0.8 in (20 mm). Factors taken into consideration for shoring design included the lateral earth pressures from the fill and native soils, groundwater pressures, temporary construction loads (e.g., crane or heavy plant/equipment), and permanent structural requirements. The subsurface conditions at this site typically consisted of fill (cohesive and granular), overlying peat and/or wood waste, overlying clayey silt to sandy silt, overlying weathered to dense to very dense clayey silt till to sandy silt till with silt layers. Localized, perched groundwater was observed within the fill, peat, wood waste and sandy silt layers above the dense till."

Jan 1, 2017

By J. W. Lyman

The U.S. Bureau of Mines investigated methods of separating valuable rare-earth materials from Fe in neodymium iron boron (NdFeB) magnet scrap. A selective oxidation treatment of the scrap oxidized the rare-earth portion while leaving elemental Fe. Magnetic and leaching procedures were tried for separating the metallic Fe and rare-earth oxides, but the extremely fine grain size of the oxidized scrap prevented recovery by either technique. The best separation of rare earths from bulk NdFeB magnet scrap was obtained by dissolution with H2S04 followed by precipitation of recyclable rare-earth salts. By precipitating neodymium-alkali sulfate double salts as an intermediate that can be converted to a variety of useful products, many materials-handling and economic disadvantages found with direct precipitation with fluoride or oxalate were avoided. Iron was removed from magnet leach solutions by precipitation as a jarosite, eliminating a major disposal problem. Research was also conducted with contaminated mixed SmCo5 and NdFeB swarf. Using a flotation-leaching technique allows the SmCo5 to concentrate in the froth, while the grinding-medium contaminant sinks and is removed as tailing. The NdFeB is dissolved by H2S04 during the process.

Jan 1, 2010

By G. ALBORNOZ, S. Utili, A. AGOSTI, C. VALDERRAMA, R. PELL, N. Morales

The steepness of the slopes of an open pit mine has a substantial influence on the financial return of the mine. The paper proposes a novel design methodology where overall steeper pitwalls are employed without compromising the safety of the mine. In current design practice, pitwall profiles are often planar in cross-section within each rock layer; i.e., the profile inclination across each layer tends to be constant. Here instead, a new geotechnical software, OptimalSlope, is employed to determine optimal pitwall profiles of depth varying inclination. OptimalSlope seeks the solution of a mathematical optimization problem where the overall steepness of the pitwall, from crest to toe, is maximized for an assigned lithology, geotechnical properties, and factor of safety (FoS). Bench geometries (bench height, face inclination, minimum berm width) are imposed in the optimization as constraints which bind the maximum local inclination of the sought optimal profile together with any other constraints such as geological discontinuities that may influence slope failure. The obtained optimal profiles are always steeper than their planar counterparts (i.e., the planar profiles exhibiting the same FoS) up to 8° depending on rock type and severity of constraints on local inclinations. The design of a copper mine is first carried out employing planar pitwalls, secondly adopting the optimal pitwall profiles determined by OptimalSlope. The adoption of optimal slope profiles leads to a 34% higher net present value and reductions of carbon footprint and energy consumption of 0.17 Mt CO2 eq and 82.5 million MJ respectively due to a 15% reduction of rockwaste volume.

Feb 9, 2022