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By Theophile Yameogo

The rock mechanics literature has documented the challenges, failures and successes of tunneling through weak rocks. Cases usually deal with low RMR rock masses or high stresses in a fractured zone. With the combination of 5MPa water pressure, 14 RMR ground with clay infillings and ground freeze walls, the case of the 510-8225N development drift at McArthur River is certainly much more challenging, especially when high grade uranium production is at stake. The article explains the excavation and the ground control techniques that were used to overcome the challenges of development at the Unconformity in the Athabasca Basin.

Aug 1, 2010

By W J Fisher

Northern Australia leads in world-class mineral deposits' is a bold statement. First there must be a starting point. Land north of the Tropic of Capricorn (23¦ 26' 5") will be regarded as Northern Australia covering nearly 40 per cent of the land surface of Australia. As opposed to land south of the Tropic of Capricorn, it should be regarded as Tropical Northern Australia and for the sake of brevity, (TNA) Refer Figure 1. Apart from the tyranny of distance from centres of power and population in the temperate zone, it suffered in the past from the belief that the tropics are unsuited for European workers and from the lack of infrastructure. Outstanding mineral deposits of iron, base metals, gold and diamonds, discovered and developed in the past three decades, provided the substance for the title. There are many world-class mines producing and there are mineral deposits neutralised through Government policy. TNA can maintain its lead in world-class mineral deposits provided Government policy will stop partitioning the land and decreasing that available for exploration. Let's look at what we have that is world-class. In Western TNA iron ore deposits at Paraburdoo, Mt Tom Price, Marandoo, gold at Telfer, diamonds at Argyle. In central TNA uranium at Ranger and Jabiluka, lead-zinc-silver at McArthur River, gold at the Tanami, manganese at Groote Eylandt and bauxite at Gove. In eastern TNA Mt Isa, Hilton, Century zinc-lead, bauxite at Weipa, gold at Kidston, Mt Leyshon, magnesite at Yamba and coal mines in the Bowen Basin. Those mines or deposits stand out yet are only an indication of the numerous lesser mines and of mineral deposits depending for development on market demand and/or changes in Government policy, eg 'The Three Mines' policy. Very large areas of mineral rich structures in the western, central and eastern parts of TNA are concealed below flat lying comparatively young unmineralised sediments. The Great Artisan basin sediments in eastern TNA can and do host oil shale and non metallic minerals. Nearly 40 per cent of western TNA is covered by the Great Sandy Desert. The Canning Track, with a series of 54 wells, was constructed by surveyor Alfred Canning in 1908 - 1910 with great difficulty. It extends 1700 kilometres from Halls Creek in the north to the gold town of Wiluna in the south, through the Great and Little Sandy Deserts. Gold explorers are following favourable structures extending to the north east below the sediments and sand hills covering the track. Half of central TNA's mineral structures are concealed by the Tanami desert and the Cretaceous sediments covering the pastoral regions of the Barkly Tableland and the Daly Waters to Top Springs pastoral areas. The Georgina Basin in the south eastern section is part of the concealment.

Jan 1, 1994

By J G Bastias

It is sometimes necessary to resort to extremes in order to call attention to something that is pertinent to safety in mining. When some of the experts in occupational safety talk about this topic, they usually refer to a 'regulation' established by the Romans which stated that, due to the health hazards, usually death, no Romans but only slaves should work in mining. Since the time of the Roman Empire, a lot of ground has been covered in the field of mine safety. Nowadays, it can be said that occupational safety is being seriously addressed, with the result that the number of mining accidents has reduced dramatically, fatalities in this industry are less frequent, and the rate of accidents compared with other activities, such as construction or fanning, is low. This achievement has been possible initially through government legislation and by procedures established by the mining companies themselves. However, the dilemma for government is whether to regulate and if so, how much. It is pleasing to observe that most companies are establishing working procedures which conform with new government legislation, placing strong emphasis on the duty of care for mine employees. There will always be some regulatory aspects of legislation, and perhaps the best example of this is in the use of mine hoists where there are no international or Australian standards, and the regulations applied are of an empirical nature that err on the side of safety.

Jan 1, 1994

By Kenneth N. Han

The effect of anions such as sulfate, chloride, and nitrate on the solubility of rare earth element-bearing phosphates and fluorocarbonates has been examined using relevant thermodynamic data. The study has found that these anions have significant influences on the overall dissolution of rare earth elements (REEs) from various sources in the aqueous media. The thermodynamic calculations in this study have indicated that the speciation of REEs with the anions tends to increase the overall solubility of the REE-bearing minerals. However, in some cases, strong precipitation of REEs with some of these anions causes an adverse effect on the solubility of these elements. It has been found that sulfate ion has the most pronounced effect on the solubility compared to nitrate and chloride, in which the latter two acids exhibited almost identical results. The calculated results have indicated that REE-oxide (hydrated) is the easiest compound to dissolve, followed by carbonate, phosphate, fluoride, sulfate, fluoro-carbonate, and oxalate in that order.

By W. R. Reed

This study evaluates the roof-bolter canopy air curtain (CAC) system in an exhausting face ventilation system, demonstrating its effectiveness and illustrating the CAC protection zones. Two scenarios are considered: (1) a roof-bolting machine in the center of the entry for installation of the fifth row of bolts from the face, and (2) a roof-bolting machine positioned close to the face for the installation of the last row of bolts. In both scenarios, the bolting machine is placed in an environment that contains 6.0 mg/m3 of respirable dust and is ventilated by an exhaust curtain with 9,000 cfm (4.25 m3/s) of air to simulate the roof-bolter machine operating downstream of a continuous mining machine. Two operation positions are simulated at the same bolting location: dual drill heads in the inward position for two inside bolts and in the outward position for two outside bolts. The influence of the CAC on airflows and dust dispersion is evaluated with the CAC operating at 250 cfm (0.12 m3/s) with dust reductions ranging from 39.5 to 82.8 percent. When the roof bolter is operated close to the face, increasing CAC airflow was required for adequate protection, as the dust reductions can be as low as 39.5 percent. Increasing CAC airflows to 350 cfm (0.17 m3/s) and 450 cfm (0.21 m3/s) were evaluated, demonstrating that dust reductions increased to 59.7 percent (350 cfm) and 72.0 percent (450 cfm). These results revealed improvement in respirable dust reductions compared to the CAC airflows at 250 cfm when the bolter is operated close to the face, showing the CAC can provide protection against high respirable dust concentrations for roof-bolter operators.

By Qinghua Tian, Zhipeng Xu, Dong Li, Xueyi Guo, Liu Zhu

A possible process for extracting tellurium and antimony from a residue generated in alkaline sulfide leaching of telluriumbearing alkaline skimming slag was proposed. The central composite design was employed to define the optimal leaching conditions for tellurium and antimony extractions from the residue sample. Using a 23 factorial matrix, the best performance for tellurium and antimony extractions (96.36% and 99.64%) were obtained at 175 g L−1 Na2S concentration for 80 °C during 60 min. The notable degree for influencing tellurium and antimony extractions was leaching temperature, Na2S concentration, and leaching time. The analysis of variance results indicated that the regression model was significant and suitable to be used for the optimization of independent variables within the range. The model was validated under optimal operating conditions based on the experimental design results. Antimony and tellurium in the leach liquor were separated and recovered by H2O2 oxidation followed by Na2S-Na2SO3 reduction. 98.93% of antimony was precipitated selectively during H2O2 oxidation, while 95.06% of tellurium was precipitated during Na2S-Na2SO3 reduction. NaSb(OH)6 and elemental tellurium was obtained as the product.

By F Rashidinejad

Iran has had an active mining sector for some 7000 years. Exceptional in terms of its mineral diversity, Iran produces 62 minerals, and is ranked among the world’s 15 most mineral-rich countries. Many people around the world know Iran as one of the major petroleum exporters. Oil and natural gas dominate Iran’s economy, and oil exports provide the principal source of income, contributing more than 80 per cent of foreign exchange earnings. Transformation of Iran from an oil exporter to an independent country to oil has been on the table for many years, even before the Islamic Revolution of 1979. Development of the Iran’s mineral industry is one of the major replacements for petroleum exports. In the last decade, Iran invested billion dollars in the mining and mineral industry sectors and to increase the added value, tried to export processed minerals instead of the raw materials. In accordance with the ‘20-year Perspective 2025’ that targeted by the Supreme Leader, Iran will be a country with the first rank in economy, science and technology in its region. The objectives over this perspective include briefly increasing annual production to 55 Mt of crude steel, 800 000 tonne of copper cathode, 1.5 Mt of aluminium, 200 Mt mineral products, 300 000 tonne of zinc and 5 000 kg of gold. These goals are achievable in normal circumstances, but concurrency of the 20-year Perspective 2025 with commencement of the UN Security Council sanctions against Iran, frustrated objectives of the perspective, at least the ones related to the mining and mineral industry sectors. This paper tries to elaborate the development programs and following challenges for the mining activities of Iran by 2025.

Nov 22, 2011

By Jim Gebhardt

Douglas W. Fuerstenau (DWF) grew up on a farm and in several small communities in rural South Dakota during the depression years, where he learned the value of hard work. Working hard can produce results but being clever and hardworking will give you a bright future. In his later school years, Fuerstenau’s family moved to Rapid City where his intellectual curiosity and capacity helped him graduate with a B.S. in Metallurgical Engineering from the South Dakota School of Mines and Technology in 1949. His technical interests led to graduate studies and completion of a master’s degree from the Montana School of Mines in 1950 and Sc.D. degree from the Massachusetts Institute of Technology (MIT) in 1953.

By RALPH BALTES, AMIR EHSAN KIANFAR, FABIAN UTH, ELISABETH CLAUSEN

  Underground positioning and communication are essential technologies for the future of underground mining operations. In contrast to other positioning and communication technologies such as wireless local area network (WLAN) or radio frequency identification (RFID), ultra-wideband (UWB) radio technology provides significant benefits like accurate and robust positioning of mobile machine equipment, which is indispensable for future autonomous systems in underground mining processes, such as production, transportation and auxiliary operations. Among these technologies, UWB offers many advantages, including higher accuracy, robustness, resistance against noise and multipath effects, and low power consumption [1,2]. Underground automation and localization systems benefit from these advantages and use the technology to improve efficiency and safety. There are many studies being carried out on this technology to increase the results’ accuracy, energy sufficiency and more. Two robust UWB modules that were developed for underground positioning and collision avoidance with regard to human safety in underground mining operations are introduced. The measurement results of tests carried out in an underground mine are discussed as well to confirm the functionality of the system.

By Linge HG, Klauber C

The key element in the carbon-in-pulp process for gold processing is the loading of dissolved Au(CN)2 from solution onto activated carbon. The mechanism and kinetics of this step have been examined by solution adsorption-desorption and X-ray photoelectron spectroscopy for both coconut derived activated carbon and peat-based activated carbon. The results show that these carbon types have the same mechanism and kinetics of adsorption. There is no contribution to the bonding from carbon-oxygen functionalities on the carbon surface, as has been invariably supposed in all previous theories for the mechanism of the reaction. It is shown that Au(CN)Z is reversibly adsorbed intact on and parallel to the graphitic planes of the carbon with the formation of a weak carbon-gold n-donor bond. The kinetic measurement of carbon gold loading reactivity is discussed and use of the Murdoch equation for this test is critically assessed.

Jan 1, 1989

By Alexander N. Winchell

"The deposits of the east end of the Mesabi Range cover very large areas, and consist of the same taconite that produces the hematite of the central and western Mesabi. It is not deeply covered with drift, but outcrops boldly in large masses. It is not concentrated locally into enriched bodies separated by leaner areas, but is all a fairly uniform, hard, banded, unaltered chert, carrying about 25 to 30 per cent iron as magnetite.The Mesabi Iron Company, organized by Hayden, Stone & Co., and under the direction of D. C. Jackling, has taken over these deposits and is building a Concentrating plant at the new town of Babbitt, about fourteen miles east of Mesaba, Minn. This plant is to have a capacity of 2,000 to 3,000 tons per day, and is based on the application to this low grade material of the methods which have made the so-called porphyry copper properties so successful.In 1916, an experimental mill was built in Duluth; containing full sized machinery and capable of handling from 100 to 200 tons daily. A considerable tonnage of material was concentrated here during 1916, 1917 and 1918. The work showed that the resulting product could be varied, almost at will, between 60 per cent and 70 per cent iron and .006 per cent to .030 per' cent phosphorus, and that this could be made on a large scale well within the limits of cost set by iron trade conditions. A small special cargo was sent down the lakes, late in 1918, assaying 63.27 per cent iron (natural and dry) and .008 per cent phosphorus; but it is assumed that large scale shipments will normally be of a Bessemer' grade carrying about 63 per cent iron and .020 per cent to .030 per cent phosphorus. This material is a sinter, carrying only traces of sulphur and titanium, with silica between 6 per cent and 10 , per cent, and alumina, lime, magnesia, and manganese, each below 1 per cent. Some of the iron in this sinter is hematite and some is magnetite, the percentages varying according to the treatment given on the sintering machine. Like the analyses, this hematite percentage is within reasonable control. Sinter made from finely ground magnetite has much the structure of coke, being firm yet porous, and gives good account of itself in the blast furnace."

Jan 1, 1920

By Ali Ekrem Aritan

In this study, the vibration exposure of excavator operators working regularly in 25 different natural-stone quarries was measured. In addition, the relationship between vibration exposure and rock properties was investigated. Gloved and ungloved vibration measurements were performed and revealed that antivibration gloves reduce excavator operators’ vibration exposure by 7.10 to 25.95 percent. Samples from each quarry were characterized with rock mechanics tests. The correlations between the hand-arm vibration measurements and the natural stone’s physical-mechanical properties, such as uniaxial compressive strength, Shore hardness, Knoop hardness, apparent density and total porosity were determined to be more than 70 percent. One finding of the study was that the health risk in excavators cannot be reduced sufficiently by the sole use of antivibration gloves. Furthermore, the excavation of any rock with a Knoop hardness above 121 is associated with an 81 percent risk of hand-arm vibration. To increase awareness of the danger of vibration exposure for natural-stone miners, training programs should be provided, and technical and operational changes should be implemented.

By MOHAMMED AMINE BELMI, ANAS DRIOUCH, ABDELAZIZ LAHMILI, LATIFA OUADIF

The mineral industry uses significant amounts of water in processing. Thus, sustainable practices with the processing of ores are of critical importance. An impact tester was used to measure the adhesion force between particles and a glass disk [1,2]. A removal force was caused by the impact of the disk/particle containing a puck with a stopper. Johnson-Kendall-Roberts (JKR) theory [3] was used to determine the interfacial energy between the particles and the substrate. Capillary condensation of water can occur between the particle and surfaces in humid environments. The adhesion of particles on rough surfaces has been studied previously [4-10]. The research presented herein combines both variables to separate particle types with minimal water usage.

By HASSAN E. EL-SHALL, AYMAN A. EL-MIDANY, KERRI-ANN A. HUE

Modifying the hydrophobicity of clay is necessary to accommodate large mycotoxin molecules such as zearalenone (ZEN). In this study, tricaprylmethylammonium (TCMA) chloride and common corn oil were used to modify clay. The results indicate that more than 90 percent of ZEN could be removed using clays modified by TCMA and corn oil at acidic and neutral pH due to the expansion of intergallery spacing as a result of TCMA surfactant intercalation within the clay-forming layers. The removal percentage depends on the pH and amount of clay used. Complete removal can be achieved at acidic pH and small clay amount.

By G D. McDonald

Flinders Mines is an ASX300 iron ore explorer and developer with a tenement package located in the Hamersley Ranges region of Western Australia, approximately 70 km north of Tom Price. Exploration over the past three years has identified a Global Resource in excess of 740 Mt at a grade of 55.4 per cent Fe (+50 per cent Fe cut-off). This resource is spread across multiple deposits and has been divided into a number of mineralisation type domains based on geometallurgical and geochemical boundaries. These domains are comprised of transported haematite rich detrital iron deposits (DID) and goethite dominant Channel iron deposits (CID) as well as in situ bedded Brockman iron deposits (BID). On the basis of differences in physical and chemical characteristics, the DID have been divided into four discrete units. The four DID units form a stratigraphic sequence with the iron grade increasing and the contaminant concentrations decreasing with depth. The upper DID unit is lower grade and currently unlikely to provide a marketable product, without signifi cant beneficiation. The lower three DID units, together with the CID and BID, are of a higher quality and have the potential to yield marketable ore. The ability to define and recognise these different units has resulted in a more reliable and robust geological interpretation and hence greater confidence in the resulting resource model. This has been evident in the excellent conversion of inferred to indicated resources.

Jul 11, 2011

By S. S. SHINDE, P. C. JIKAR, N. B. DHOKEY

Mill scale is an oxide waste product of steel mills, containing around 70 percent iron and other allied impurities. In the present context, a dynamic prototype counter-current reactor (CCR) was used for the experimentation and simulation of a particle bed using the discrete element method (DEM). Mill scale was pulverized to ASTM mesh range 140 (106 μm)/+ 270 (53 μm) and oxidized in a CCR to make a single oxide Fe2O3 phase by maintaining the required thermodynamic conditions, such as pure oxygen at 1,100 °C. This oxidized powder was then subjected to a reduction reaction in the CCR, with gas mixture (H2:N2) ratio of 1:4 at 875±5 °C for filling degree, fd , and reactor revolution, ω, ranging from 5.38 to 16.14 percent and 2 to 5 rpm, respectively. A creeping fluid flow condition (Re < 1) and natural heat convection (Gr/Re2 >> 1) were maintained during the solid–gas reaction, and the particle-bed behavior was quantified by Froude number for the optimum operating window. The simulation was validated with the experimental results of reactor reaction product by X-ray diffraction (XRD) and scanning electron microscope (SEM) images.

By R Kjar

Globally, it is anticipated that the mineral sands industry will enter a period of short supply. Demand for both titanium dioxide and zircon is forecast to continue increasing, with new projects needed to come on-stream to fill the supply gap. Victoria is well placed under this scenario as a source due to the high quality of its mineral assemblage, its excellent resource grade and the globally significant size of its mineral sands resources.Australia’s mineral sands rich Murray Basin remains under-developed, especially at its extensive Victorian margins. Development to date has not progressed adequately for the reasons of technology difficulty, history of competition with other jurisdictions and the absence of a platform that requires development as a consideration for security of tenure. Victoria’s mineral sands potential is not just about the Murray Basin, in addition, there have been discoveries in the Gippsland Basin and prospective sites in the Gippsland Basin remain under-explored. Key problems included the lack of available ground for potential developers and the intellectual property of solutions to technological problems associated with the fine grained mineral deposits belonging to a previous developer (with patents now expired).As such, the timing is right to re-visit the potential of the Murray Basin as a site for long-term development with high returns based on current and predicted prices.In order to understand why Victoria’s earth resources in general, and mineral sands in particular, remain under-explored and undeveloped, the Department of Primary Industries initiated an internal review of its role in encouraging and supporting investment in the earth resources sector.As a result, the Victorian Government has committed to taking action to encourage effective ground turnover and acknowledges that a new focus on engagement with industry is needed to bring new investment to the State. The revision of the Mineral Resources (Sustainable Development) Act 1990 provides an opportunity for the government to better align its legislative processes with industry project lifecycles and facilitate access to valuable resources that currently remain undeveloped.Victoria has a track record in assisting projects reach development stage. Iluka currently has two operations in the State in addition to its mineral separation plant that is capable of processing HMC from its South Australian operations. Iluka is expected to ramp up its Murray Basin Stage 2 operations with the WRP mine scheduled to come on line in early 2012. Meanwhile, Astron is actively seeking partners for its Donald Mineral Sands project. The project is becoming increasingly attractive given the recent price hike in zircon; Astron has access to an estimated five to 6 Mt of zircon in its Donald WIM 250 deposit.Given its substantial and valuable mineral sands endowments, the State of Victoria should sensibly be the centre of future investment in project development. However, as previously mentioned this is currently not the case. The Government is therefore committed to implementing new measures that protect security of tenure but ensure that genuine companies can access endowments where they have a clear intent to work those resources.

Oct 5, 2011

By R Hartner

Digital optical microscopy (DOM) and automated SEM-based (ASEM) mineralogy systems (MLA, QEMSCAN) have experienced significant developments within the last decade. However these developments have been independent from each other and the two mineralogical techniques have so far not yet been integrated to combine the strengths and technical benefits of both analytical platforms. This detailed comprehensive mineralogical information is critical support for geometallurgy.Major hardware and software advances in DOM in the last few years have provided important new capabilities with potential applications to automated mineralogy. These technological advances have been largely driven by sectors outside mining (eg medical pathology) and have not yet been widely adopted within the minerals industry. The advent of DOM offers significantly more automated mineralogy capabilities than traditional expert-mineralogist driven optical microscopy. This is based on advances in automated image acquisition, high resolution cameras for digital imaging, imaging of large areas through mosaic options, integration of multiple layers and application of advanced image analysis techniques.Ongoing research involves combining the outputs of DOM and ASEM-based microscopy to create new capabilities for integrated microscopy based on development of advanced cross-platform image fusion and data integration between DOM and ASEM (exploiting the benefits of both analytical platforms). This requires non-linear image registration and transfer of mineralogical identification from ASEM to DOM systems using sophisticated image manipulation and data analysis software.Examples will be given of image fusion and data registration for a range of different ore types. Image fusion techniques are demonstrated using a porphyry copper deposit sample where sulfides and precious metals are classified using the MLA and gangue mineralogy obtained from DOM images. Data integration enables creation of a library containing optical property variability information for minerals identified by the MLA; thus reducing the reliance on skilled mineral identification by supplementing human interpretation

Sep 5, 2011

By Richard A. Thomas, Liming Yuan, Lihong Zhou, James H. Rowland

Hydrogen (H2) gas released during battery charging can result in cross-interference for carbon monoxide (CO) sensors used for early fire detection and compromise the integrity of the mine atmospheric monitoring system (AMS). In this study, a series of laboratory-scale and full-scale experiments were conducted to evaluate the responses of different CO sensors to H2 gas. In the laboratory-scale experiments, constant H2 concentrations in the airflow, from 100 to 500 ppm, pass through sensors. While in the full-scale experiments, increasing H2 concentrations generated as a byproduct from charging the batteries at the battery charging station rise to the sensors under different ventilation scenarios. The H2 concentrations at the CO sensor location were measured using H2 sensors and were correlated with the CO sensor response. The effects of ventilation and sensor location on the CO sensors responses were also analyzed. The results of this study can help mining companies to select appropriate CO sensors and improve the deployment of these sensors to ensure the safeguard of underground miners.

By Ihsan Berk Tulu, Mustafa Can Suner

The synthetic rock mass (SRM) approach is a relatively new method to study the mechanical behavior of rock masses. Recently, an SRM approach was established to estimate pillar strength from laboratory scale to in-situ dimension using the two-dimensional Universal Distinct Element Code (UDEC). In this study, the developed methodology is applied to the S-Pillar database to estimate pillar strength and failure mechanisms as a function of width-to-height ratio of the pillars. First, stone mine rocks are categorized into three as low-, medium-, and high-strength according to their uniaxial compressive strength (UCS). Later, laboratory-scale intact rocks are scaled-up to the average in-situ pillar dimensions by explicitly considering the naturally existing joint sets. It is found that the strength of the pillars with low-UCS are overestimated when compared to pillars with high-UCS. This observation is attributed to the high joint density of the pillars with high-UCS. After obtaining in-situ pillar strength, the width-to-height ratios of the pillar models varied from 0.5 to 2.0 to gain a robust understanding of pillar mechanical behavior. Tensile failure is found to govern the pillar behavior with the width-to-height ratio of 0.5 while the combination of tensile failure in rib elements and shear failure in the core