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By J Nemcik, E Baafi, I Porter, G Spinks

Spray-on liners used in the mining industry for ground support and stabilisation applications are either cement based (æshotcreteÆ) or polymer based (æthin spray-on linersÆ). Some thin spray-on liners are a blend of both polymer and cement (eg Tekflex). A small number of thin spray-on liners (TSLs) have been trialled in Australia as potential replacements for steel mesh in roadways and other underground mining applications; however, they were found to cure slowly and the cured coatings became brittle after an extended time in place. The University of Wollongong in collaboration with the Australian coal mining industry has shown that a viable polymer-based alternative to steel mesh in underground roadway support applications can be developed to eliminate the use and handling of steel mesh. The work to date has: established the feasibility of developing polymeric alternatives to steel mesh in underground roadway support applications; identified the physical and material constraints to be endured by any new polymeric skin reinforcement system by measuring the mechanical properties of steel mesh; identified materials that can be spray applied; and demonstrated that polymer mechanical properties can be optimised to produce similar mechanical properties (elastic modulus, yield stress, elongation-at-break, etc) to steel mesh. The identified materials will: allow the face support cycle to be fully automated, or at least remotely operated and installed; remove personnel from the immediate face area; and substantially improve underground roadway development rates.

Jan 1, 2008

By John S. Carman

Our industry is in trouble. Real trouble. It has never been an easy, secure business. But to-day it is engulfed in revolutionary currents. No longer can there be reliance upon the checks and balances of market forces. Supply and demand largely dictated the economics of business enterprise in simpler days. To-day politics, in particular nationalism become increasingly dominant. And as governments expand and put out tentacles of interference in the direction of the mining industry, far too little understanding is evidenced as to how that industry works. Then there is something which is relatively new -stagflation. As the prices of minerals falls, the capital investment required for new extractive facilities soars at rates which far outdistance those which are cited by governments to indicate the magnitude of inflation. To illustrate; 1) In 1971 it was calculated that $355 million would be required to bring the Cuajone property in Peru into production. Five years later that stage was reached at a cost of $680 million. 2) With the Caridad mine in Mexico, estimated capital investment doubled between 1971 and 1976. 3) The requirements calculated for Cerro Colorado in Panama have risen in two years from $560 to $800. 4) The budget of $240 million for Sar Chesmeh in Iran in 1971 had become $500 million by 1976.

Jan 1, 1977

By Ing. Ludwig Schlebusch

The significant growth of the world population and its demand for an increasing standard of living leaves no other choice than continuously augmenting industrial production and making available steadily greater quantities of raw materials at still better qualities. Therefore, any raw material has to be utilized to the greatest possible extent and processed at optimum economy on large mechanical equipment. The layout of processing facilities of large throughput rates can be based on multiple or single lines. The latter enables the application of large machines of optimum size. Proven equipment for homogenizing, classifying, separating superfine material, sorting and dewatering are-now available in optimum sizes. By the use of these large machines operating cost of pit coal preparation plant can be significantly lowered by reducing the specific requirements regarding space, capital investment, energy, operation and maintenance.

Jan 1, 1980

The minerals industry contributes to the economic growth, prosperity and quality of life of nations, particularly in areas where there might be limited opportunities for employment in other sectors. However, notwithstanding their economic importance, the minerals extraction and processing industries are considered to have significant impacts on the surrounding environment. In recent years many mines have implemented modern monitoring technology and modelling of the monitored environmental parameters to provide scientifically proven indicators about the state of the environment. The flexibility required by the minerals industry to respond dynamically to a changing natural, social and economic environment has become a major consideration. Whilst the notion of continuous improvement is embodied within most environmental management systems, what is now required is a structured audit trail which tracks the flow of resources through the production process to the ultimate environmental impact associated with their consumption, transformation and disposal. Imperial College is coordinating an EC funded project, which is developing a methodology to minimise the ?full life-cycle? impact of metalliferous mining projects, adopting an integrated approach to production and process design, and the costs involved. In order to develop a life cycle assessment (LCA) system that will incorporate different types of data related to the minerals extraction operations, a data inventory was designed and coded in an object-relational database model. The calculation procedures accounting for the input/output balance of the alternative scenarios for mining production, processing, waste disposal, monitoring, and their financial implications are being programmed into a software system. This paper presents the rational and innovative aspects of this work. The methodology developed for the life cycle database is illustrated for the mining production and gaseous emissions components of the system.

Jan 1, 2003

By Milance Mitovski, Milorad Cirkovic, Vlastimir Trujic, Dragana Živkovic

"In this article, it is analysed the possibilitis and the effects utility waste energy of process sulfuric acid production in the existing technical-technological conditions. The utility second process energy, reduction the fuels consumption, reduction environment pollution and its effects are shown, too. High heat quantity is produced as the result of exothermal reactions in the production process of sulfuric acid in Bor. A part of this heat is sufficient for the process development, and significant part of this heat presents low-temperature heat energy that is irretrievable lost. Investigations were carried out based on production of 485 t of monohydrate/day of sulfuric acid. By recovery of this heat quantity for heating purposes, about 20.000 – 25.000 t of coal/year would be saved, what would significantly improve the power efficiency of the smelter copper production. IntroductionTechnological process of copper production in RTB BOR (Serbia) produces a significant quantities of high temperature secondary (waste) heat energy that is uncontrolled “lost” in the vicinity. Secondary heat energy is produced in pyrometallurgical copper production in quantity of 1,621 kWth/kg of dry concentrate or existing heat (that presents a difference of heat at furnace outlet and heat at temperature over temperature of dew point of sulphuric acid gases) in quantity of 1,315 kWth/kg of dry concentrate. For designed capacity of Copper Smelter in Bor, the existing heat power of secondary energy is 92,111 MWt, what is an equivalent to the power of steam-turbo plant where the Rankine-Clausius heating cycle is done, and that is 28,334 MWe."

Jan 1, 2008

By S Pradhan, A Kuras, R Mahajan

This paper describes the design of the precast concrete segmental lining for the 13.1 m internal diameter and 450 mm thick, 2.4 km long mainline tunnels for the Waterview Connection project in Auckland for the New Zealand Transport Agency.The design and detailing of this segmental lining presented some noteworthy challenges, including an alignment that has sections of low cover in soft ground. Key points of interest are that this precast segmental lining is the largest to ever include steel fibres as the primary method of reinforcement and the lining includes cams on circumferential joints to control ring deformation.The paper describes some of the key design decisions that were made in a collaborative manner with the construction team, tunnel boring machine manufacturer, segment manufacturer and the designers.CITATION:Mahajan, R, Kuras, A and Pradhan, S, 2014. Design of segmental lining for Waterview Project, Auckland, New?Zealand, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 289–294 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By R. C. Dunne, W. A. Gilbert, I. J. Corrans, K. S. Liddell

After bench-scale and pilot-plant tests in which it was shown that wet high-intensity magnetic separation (WHIMS) can achieve good recoveries of gold and uranium from Witwatersrand residues, a production size machine was installed at a gold mine. The mechanical and metallurgical performance of this machine have been satisfactory, and the economics of the process are attractive. WHIMS can be combined with other unit operations like flotation for the optimization of overall gold and uranium recoveries. This concept is shown to be relevant, not only to operations for the retreatment of tailings, but to processes for the treatment of coarser material. In the latter, there is a saving in energy consumption compared with the energy required for the fine grinding of the total feed, and a material suitable for underground backfill can be produced. Improved. more cost-effective WHIMS machines currently under development are also described.

Jan 1, 1983

By Turan Uysal, Thierno Saidou Barry, MURAT ERDEMOGLU, Mustafa Birinci

Nonbauxite ores such as aluminum silicate clays and coal fly ashes have been widely considered as potential resources of alumina (Al2O3). The interest focused on these ores is due to their high alumina content. Over the years, in countries where there are little or no bauxite reserves or where the recovery of existing bauxite ores to produce alumina with the Bayer process is not economical, alternative processes have been explored. Among these processes, acid leaching is seen as the most attractive process. In the acid leaching process, heat treatment for thermal activation to destruct the refractory structure of the minerals in the ores is generally recommended as a pretreatment method. Recently, the applicability of high energy ball mills, which are useful for mechanical activation as a pretreatment method before leaching, has attracted much attention. This is a short summary of our previous review [1], giving the details of alumina manufacturing from thermally and mechanically activated clays and coal fly ashes by acid leaching.

By John J. Mancini

Elastomeric liner products have been used for over two decades in a wide variety of uses including pond liners, hazardous waste barriers, dam face rehabilitation and mining applications. Asphalt blended with polymers is enjoying renewed interest in the engineering community because of its durability, high yield attributes, fewer CQA steps due to seamless installation, and ease of installation and repair. As in other lining technologies, advancements in polymer chemistry and improvements in installation techniques have had dramatic impact on the quality of fluid-applied asphalt (FAA) membranes. Membrane 6, man­ufactured by Deery Oil, Inc. for over 16 years is a hot-applied polymer modified asphalt membrane that can be applied to a variety of substrates in a reinforced configuration or installed directly on an asphalt surface. By blending thermoplastic polymers with asphalt, very favorable stress/strain characteristics can be achieved (Chambers, 1980). Typically the membrane will yield under rel­atively low stress and also exhibit high elongation capability. In service applications where puncture resistance is a concern, fluid applied asphalt materials have the flexibility and com­pressive strength under heavy loading that leach pad designers may find attractive. Additional security is achieved if long term service life is important as in the case of radioactive waste con­tainment. The Department of Energy selected Membrane 6 over seamed liners for a surface barrier that must isolate and contain radioactive waste for 1000 years. Asphalt has a long history of use as a water-stop material and it is believed that this natural construction material combined with SBS polymers will per-form for a millennium. (Freeman, 1994) The process of installing Membrane 6 varies according to job size and the type of surface to be protected. Lining applica­tions on compacted substrates require the membrane to be applied to a scrim cloth (fig 1). Some early pioneers in FAA technology neglected this step and therefore never achieved per­formance levels that satisfied regulatory guidelines. The scrim provides a cohesive surface that promotes membrane flow while achieving high impermeability (2Xl0 '11).

Jan 1, 1996

By R. T. Sorensen

Bench-scale and continuous testing were performed to adapt the anionic process for flotation of calcium activated silica to the fine-grained hematitic-goethitic jaspers from the Marquette range, Michigan. These ores typically contain about 35 percent Fe and require grinding to about 80 to 100 percent minus 400 mesh to insure an adequate liberation of gangue from the iron oxides. A method for removal of troublesome slime fractions without excessive iron loss, by first dispersing the quartz and then selectively flocculating the iron oxides, was evolved in the laboratory and successfully accommodated to pilot plant practice. The efficiency of the flotation process was improved with respect to both reagent usage and concentrate grade and recovery by using the selective flocculation-desliming technique as a pretreatment. The benefits of the combined desliming-flotation procedure were most evident in pilot plant processing. The best tests on two ores yielded recoveries of about 84 percent in concentrates containing 65.1 percent Fe and 4.8 percent SiO2 and 66.2 percent Fe and 3.9 percent SiO2, respectively. These results are in comparison to recoveries about 10 percent lower than the above to concentrates containing 63.9 percent Fe and 6.6 percent SiO2 in the one instance, and 63.6 percent Fe and 7.2 percent SiO2 in the other, obtained by flotation without the prior desliming treatment.

Jan 1, 1967

By S. B. Patton

A computer model, which quantitatively utilizes the relationship between the interactive and dynamic processes of methane drainage, mining, and ventilation, is presented. The model includes simulation of the coalbed methane reservoir for prediction of gas-emission rates under the influence of degasification wells and longwall mining, ventilation network-generation, and ventilation simulation. As mining progresses step-wise through the coalbed-methane reservoir, the ventilation network is created and subsequently simulated, iteratively determining fan requirements to safely reduce methane concentrations. The model can be used to quantitatively study the effectiveness of methane degasification on the ventilation system in a longwall panel.

Jan 1, 1992

By J. Armitage, J. Erskine

Feed level and thickness measurements are essential in the optimization of an electric arc furnace. A precise measurement of the feed thickness and level gives operators the ability to increase the smelter efficiency and reduce the maintenance cost. Hatch has developed a radar system which is an affordable, low maintenance, and accurate level measurement system. The radar units can be installed across the furnace to measure the feed level and the feed thickness can be calculated with one slag level sounding. The present paper describes the development of radar systems as a process optimizing tool by furnace controls. The authors will discuss the challenges involved in installing eight radar units on the roof of a six-in-line electric furnace.

Jan 1, 2015

By Chuansheng Luo

If lead-zinc ores have high oxidation rate, separation of lead and zinc is very difficult. This paper studied the technology of preferential flotation by the coarse grinding and re-grinding. The lead concentrate grade is 51.40% and the lead recovery is 62.83% when feed grades Pb 1.74% and Zn 6.46% with oxidation rate being 13.75%. At same time, the zinc concentrate grade is 50.07% and its recovery is 90.01%.

Sep 1, 2012

By W. S. Ayres

A BRIEF history of the growth of the anthracite-coal preparation will give a better view-point from which to judge the present problem of separating slate from coal. At the beginning of the commercial value of anthracite, 70 years ago, only the pure portions, or " splits," of the veins were mined and shipped to market, and without any preparation or screening other than the selection, while loading, of the glassy lumps, and the rejection of the fine material and the slate that had strayed accidentally into the coal. The next step was the crushing or breaking of the coal (hence the name Lt breaker" as applied to the preparation-building), and the sizing of it by means of bars or revolving screens. This stage of its development marked the advent of the "breaker-boy " as a slate-¬picker, with his ever-increasing capriciousness. As the richer veins or ? splits " became exhausted and the market demanded a still greater output, the less-pure " splits " and the thinner veins were utilized to produce the coal. Carrying as they do a far greater percentage of impurities; particularly when removing the pillars, it became necessary to build new and better equipped preparation-plants. Finally, we are now at the highest stage of complication yet known to the art of coal-preparation. We are dealing with varying specific gravities, frictional difference, hardness, structure, and form in the pieces of coal and slate coming from many different veins, and

Dec 1, 1909

To provide accurate navigation and control of continuous mining systems.

Jan 1, 1996

By A. P. Sasmito

It is well known that underground miners are exposed to one of the most dangerous working environments on earth. As mine delve deeper, the geological factor, mine position and climate condition as well as heat generation from mining machine give rise to the mine operating temperature. This, in turn, has an adverse effect on the environment and thus leads to higher operating costs. Careful estimation and design of air flow rate, spray system, cooling load and additional ventilation auxiliary equipment are of importance to ensure safety, comfort and productivity whilst maintaining low operating cost. A computational fluid dynamics simulation approach is employed to examine underground mine ventilation in a 36 m cul-de-sac of tunnel of coal mine. The model predictions in the turbulent range were validated by comparison with published data. Different turbulence models were tested to select one that yields adequate accuracy and is computationally efficient. Effects of the following parameters are evaluated: tunnel geometry, air flow rate and inlet air temperature. The objective of the simulation is to arrive at an optimal strategy for ventilation and thermal comfort at low cost.

Aug 1, 2013

By B P. Banerjee. S Raval, P M. Ranasinghe

Simultaneous Localisation and Mapping (SLAM) is an important technology that enables autonomous robots to navigate independently and create detailed, real-time maps of their surroundings. This capability is crucial in underground mining settings, where it enhances operational efficiency and significantly strengthens safety in these subterranean environments. SLAM algorithms typically rely on identifying and using distinct geometric features, such as plane and edge features, to understand the spatial layout of the environment and to track how it evolves as the sensor moves through it. In underground roadways, the scarcity of noticeable edge features, coupled with the repetitive nature of walls and corridors, poses a significant challenge, making it difficult for these systems to distinguish one area from another. Furthermore, the absence of global navigation satellite system (GNSS) signals in underground adds more challenges, leading to the accumulation of errors in both the mapping and localisation.

Sep 1, 2024

By Carl-Eric Dr. Nilsson

Energy cost for mine ventilation in Sweden is high, especially during winter time when air must be heated. This paper presents the result from a project entitled ventilation-as-required. The term ventilation-as-required means that the required volume of fresh air should be distributed only to such areas, where mining work is going on and to be reduced to a minimum in the rest of the mine. Ventilation-as-required is a monitoring system that controls the operation and capacity of the fans and measure the air pollutant gases, i.e. carbon monoxide, nitrogen and sulphur dioxide at strategic points. It is an active system that responds when equipment is under operation. MITU proposed in 1991 a project to develop a ventiation-as¬required system and such components as transmitters and receivers for the communication between the equipment and the fans. The mining companies, Boliden Mineral AB, LKAB, Outokumpu and Ammeberg Mining Corporation joined the project and have financed a joint research and development programme supported with a grant from the Swedish Government through NUTEK. MITU proposed a second project in 1992 to the mining companies to develop an improved "intelligent" fan for scope ventilation. Boliden Mineral and LKAB joined the project and have financed a joint research and development project supported by the Swedish Government through NUTEK. The Government even made a commitment to support the investment of the first 50 fans ordered with a grant of 25% of the investment cost. The result from projects show that the target set up in the plans is more than achieved, with an energy reduction that exceeds 30% compared to previous consumption. No environmental influence due to reduced ventilation is observed in the stope when work is under progress. Dilution of exhaust gases from diesel fuel decreased from 6.000 m3/L consumed diesel fuels to 3,600 m3/L. The automatic data processing and sensor system is even increasing the security of the work so that it can be done under safer environmental conditions.

Jan 1, 1995

By A Baker

Hail Creek Mine is an open cut coal operation owned by Rio Tinto. It is located 120 km south west of Mackay in the Bowen Basin region of central Queensland. Opened in late 2003, the mine produces two high quality coking coal products that are used in the production of steel in various overseas markets. Hail Creek is a dragline and truck/shovel operation with a capacity to mine eight million tonnes per annum. In 2010, the production was more than seven million tonnes.Traditionally, coal seam edge loss had been minimised on site by the practice of coal edge buffering. Importing buffer material can be quite expensive as it requires a large involvement from the truck and shovel or dozer fleet. In order to minimise this expense, a program of front splitting was introduced on site. Front splitting however involves an additional blast interaction which places added pressure on mining schedules. Both these methods of coal protection demonstrated a significant benefit with coal loss being reduced by approximately seven per cent (absolute) compared to traditional cast blasting.With the application of electronic detonators at Hail Creek the new blasting practice of dynamic buffering is able to be performed on site. Dynamic buffering refers to a blasting practice where two or three separate blasts are initiated during the same blasting event (front-split, cast and at times presplit). The process involves firing a front-split and allowing it to have time to settle and buffer the coal edge prior to the cast blast initiating. This practice is only made possible with the use of electronic detonators and the effective absence of a surface burning front. Current practice at site involves the front-split being fired (occasionally at the same time as the presplit) and the main cast blast being initiated several seconds later. Dynamic buffering is now used for all cast blasts to coal at Hail Creek. Electronic detonators have allowed Hail Creek to achieve reduced coal losses by buffering the coal edge without compromising the mining schedule.

Nov 8, 2011

By M. Carvalho

The primary motivation underlying the proposal of polygeneration systems for mine sites is to increase the efficient use of natural resources by combining different technologies and energy resources while satisfying energy service demands. For many mineral producers, particularly in Canada?s mining extremes of climate and depth, energy in support of mineral production can be the second largest cost centre after labour. A generic methodology is proposed for the design of energy supply systems in mine sites, based on a search for the minimum discounted cost of energy supplied for all feasible different plant configurations. These configurations can be represented within a connectivity matrix which corresponds to a network representation. A Mixed Integer Programming formulation is set out for the multiperiod synthesis and operational planning problem. This is characterized by i) binary variables for the selection of technologies, ii) integer variables for the determination of the number of units installed, and iii) by continuous variables for the representation of energy and economic flows. Through the integration of particular energy supply strategies matching specific mine circumstances (on-grid, remote, degree days, etc) and consideration of technologies that improve energy efficiency, hitherto not considered new technologies and demand management systems or new perspectives on optimal mine site energy supply can be investigated. Some of these investigations identify the economic conditions through which biomass energy feedstocks should be used, for direct heat production, for gasification and providing for Fischer-Tropsch syndiesel manufacture. As well as integrating demand from mobile diesel-fuelled plant into an optimization procedure that hitherto has only been considered for static energy production and consumption plant, this analysis shows how the techniques can be used to explore economic conditions of threshold prices for biomass (purpose-grown biomass and peat are considered herein) and trucked-in diesel. The methodology also allows for electricity and syngas storage and diesel and biomass bunkering. Within the paper the energy demands for a remote, open pit mining operation located in Northern Ontario are considered as a case study to illustrate the technique and investigations. As expected, for mines close to electricity, natural gas, and diesel distribution infrastructures, the optimal choice is to connect. When a constraint is applied specifying that connection is not possible, as would be for the case exemplified, the optimal choice includes some of the more exotic options for mine site energy supply.

Aug 1, 2013