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By Garry M. Johnston, Matthew L. Sutcliffe, Nicholas J. Welham

"The predominant current processes for the treatment of oxidized copper–cobalt ores use a reductive acid leach to bring the desired metals into solution. However, the indiscriminate nature of acid leaching results in a solution, akin to a metal soup, containing not only the Cu and Co but also an extensive suite of other metals. These other metals, notably Fe, Mn, Al, Ca, Mg and Si, all have to be eliminated from solution before the copper and cobalt can be recovered. Generally precipitation processes are used, but these tend to result in significant losses of copper and/or more usually cobalt from solution, leading to reduced recoveries. The AmmLeach® process uses ammonia-based chemistry to selectively leach the target metals, leaving the rest behind in the leach residue. This approach eliminates any need to clean the solution of unwanted metals and the consequent metal losses. After solid–liquid separation, the leach solution is immediately subjected to separation and concentration of the copper and cobalt using solvent extraction and electrowinning. INTRODUCTION The Copper Belt extends through the northern part of Zambia and the southern province of Katanga in the Democratic Republic of Congo (DRC) and contains the richest and highest grade deposits of copper and cobalt remaining in the world. Whilst there are a number of mines that produce sulphide concentrates, using froth flotation, the largest deposits are those where near-surface sulphides have been weathered over time to form oxides. The oxides cannot be concentrated by conventional physical means to give high recoveries. Despite this, a number of dense medium separation plants have been installed and used to produce a higher grade concentrate which is typically exported (while the rejects, typically 2 to 3% Cu are stockpiled for treatment at a later date). These plants generally have low recoveries and can only be used on the dwindling supply of high grade materials. In exporting the concentrate, little value adding is undertaken within the country, thus greatly reducing the economic benefits to the country. Recent changes to the regulations in the DRC will effectively ban the export of low value ores, concentrates and intermediates in favour of high value metals. This will necessitate mines to install new processing circuits in order to comply with these regulations. The head grade of ores currently being treated in the DRC is slowly decreasing as the extremely high grade materials are being selectively mined out. In many cases, the removal of a small volume of high grade materials leaves a much larger volume of economically marginal ore behind. This is due to a desire for short-term profits overtaking long-term prosperity. The remaining ore, which in many cases is still of relatively high value by world class standards, is likely to be only treatable by low cost heap leaching. There are some initial trials of heap leaching within the DRC, but implementation at a large scale has yet to be adopted."

Jan 1, 2015

By M. E. Alam

In the present study, 1.1 volume percent of nano size copper was incorporated into pure tin using hybrid microwave sintering assisted powder metallurgy route. Microwave sintered samples were extruded both at room temperature and at 230 °C. Microstructural characterization studies were conducted on the extruded samples to investigate the distribution characteristics of secondary phase and grain morphology. Room temperature tensile test results revealed that hot extruded Sn-Cu samples exhibited higher strengths (~ 41%, in case of 0.2% yield strength and ~ 38%, in case of ultimate tensile strength) and ductility (~ 15%) when compared to room temperature extruded samples. On the contrary, the tensile properties of pure tin remained independent of extrusion temperature. An attempt is made in this study to correlate the effect of extrusion temperature on the microstructural evolution and tensile properties of Sn-Cu solder.

Jan 1, 2009

By D Craw, J Pope

The Greenland Group, Westland, can be characterised with respect to environmental issues by the application of a GIS database (DAME), and specific sampling campaigns. Waters draining gold mineralised areas have a distinctive chemistry characterised by neutral pH and arsenic as a trace element. The acid neutralising capacity (ANC) from carbonates usually exceeds the maximum potential acidity (MPA) from sulphides resulting in circum-neutral pH. These waters are readily distinguishable from waters draining coal mine related areas, which commonly have low pH (~4) and low As concentrations (~0.1 ppm). In contrast, dissolved arsenic mobilised from Greenland Group historic gold mining areas is up to 2.4 ppm. This As mobilisation is controlled by the secondary As mineral, scorodite (FeAsO2+2H2O). Maximum dissolved As concentrations increase with increasing pH, corresponding to the increasing solubility of scorodite with increasing pH. Dissolved As is attenuated by dilution, precipitation of scorodite, and/or adsorption to iron oxyhydroxide (HFO). Adsorption to HFO is an important attenuation mechanism in and adjacent to many mine sites. HFO is abundant at mine sites where pyrite was abundant in fresh rock, such as where the mineralised zone is dominated by disseminated pyrite. Pyrite, and resulting HFO, are relatively rare where mineralisation occurred as well-defined quartz veins. Localised HFO occurs also where ankerite oxidises in host rocks. Arsenic output flux (ca. 25 g/day) from historic gold mine sites is commonly less than the natural background flux from mineralised rocks (>5000 g/day).

Jan 1, 2006

The mining industry has recognised for some time the importance of supporting programs which serve to educate the Australian public about the socio-economic benefits of mineral resource development. More recently, industry leaders have realised that the future development of the industry will depend on attracting sufficient young people to commit to a career in the industry. Apart from lending support to the traditional education institutions in Australia, the industry now has the opportunity to participate in the development of education programs in museums. Whilst historic, mining-related theme parks such as Sovereign Hill and Coal Creek in Victoria serve very effectively the objective of relating past mining activities to the socio-economic development of Australia, there still exists the need to provide a facility which, under the same roof, excites interest in geology, mining, mineral processing and the role of minerals and energy in modern society. The redeveloped Geological and Mining Museum (the "Mining Museum"), which is located in The Rocks area of Sydney, meets this objective. With the central themes of formation and transformation this new Museum, which aims to be the best of its type in the world, will use modern museum exhibit techniques and the resources of the Minerals and Energy Information Centre to educate the community including teachers and school children. In the best tradition of museums, outstanding mineral and other collections will complement a comprehensive range of interactive, high technology exhibits which will include a number of exploratory "hands on" facilities. Australian companies are joining with Government to fund this exciting new museum. There is still a need for industry professionals to realise that a modern "mining" museum is no longer just a repository for objects of mining heritage but is also an important centre which serves as an important educational and public relations interface. The Education Section of the new "Mining Museum", which is linked closely with the new Minerals and Energy Information Centre, will be working closely with appropriate mining-related Tertiary institutions to develop specific career programs aimed at secondary students who wish to pursue a career in the mineral resource industries.

Jan 1, 1989

By Steven D. Wirch

Abandoned underground coal mine areas must either be sealed or ventilated to comply with federal mine regulations. Ventilation of these abandoned areas is often impractical due to roof falls and inadequate primary mine ventilation. If the area is sealed, a very complex ventilation system is set up. In which the gob "breathes" in and out due to barometric pressure fluctuations. The Gob Assistant is a computer program (for use on IBM compatible personal computers) which allows the prediction of air flows into and out of a sealed mine area. Gas flows with applicable control techniques are also modeled. This information is presented to the user who will decide which control technique, or combination of techniques will ultimately be applied. The Gob Assistant is an intelligent gob simulator that can reduce the guesswork involved in predicting the effects of sealing and control techniques before they are applied. This paper provides the fundamental principles upon which the Gob Assistant is based, verification of these principles, and an explanation of how these principles were integrated into the Gob Assistant.

Jan 1, 1988

By Sandeep Kumar Jeripotula, Govinda Raj Mandela, Aruna Manglapady

Dumper operators are frequently exposed to whole body vibration (WBV) in surface mines. Surface mining activities involve the amalgamation of comparatively high intensity of vibration and extended exposure durations. Efficient risk reduction mandates knowing of important phases of a task that poses a threat to health of dumper operators. So far in India very limited studies have been reported on WBV exposure with regard to surface mines. This paper evaluates WBV of dumper operators based on ISO 2631-1:1997 Standards and European Union (EU) Directive 2002 for different phases of job cycle. Six dumpers were considered for this study and the vibration measurements were made for all the four phases of the job cycle by placing the triaxial accelerometer on the operator’s seat-surface and at the seat-back, independently. The findings of the study revealed that the haulage task (loaded travel and empty travel) remains the chief contributor to vibration exposure according to seat-surface and seat-back measurements. Maximum frequency weighted root mean square (RMS) of 1.12 m/s2 and 1.09 m/s2 were reported for empty travel task for seat-surface and seat-back measurements, respectively. For seat-surface measurements based on RMS, Z axis remains as the dominant axis of vibration for all the dumpers during haulage task, whereas for seat-back measurements, the dominant axis varies between X and Y. Exposure action value (EAV) based on RMS has exceeded the threshold value of 0.5 m/s2 for all the dumpers during loaded travel and empty travel for seat-surface as well as for seat-back measurements.

By Peter White

Mine Planning Shaft Collar Shaft Sinking Raises Ramp Underground Water Storage

May 1, 2009

The No. 2 Ore-shaft, at Mount Isa Mines Limited, involving the use of boreholes as ropeways for the upper portion thereof, constitutes, we believe, a unique feature in hoisting installations. The boreholes were sunk from the surface to a depth of 390 ft., thus eliminating the necessity of erecting the hoist at an underground location or construction of the shaft for this distance. Fig. 1, a diagrammatic cross-section through the shaft, shows the complete installation from the surface down to the first loading station below No. 7 haulage level.During the latter part of 1936, conditions encountered in sinking the Main Ore shaft made it impracticable and uneconomical to continue deepening it to serve haulage levels below the present No. 5-level. Plans were therefore made for an interior shaft, to serve new lower levels, that terminated above No. 5-level so that ore hoisted could be drawn off on this level and transported to the Main Ore shaft for final conveyance to the mill crude ore bin.Referring again to Fig. 1, it is apparent that the section above No. 4-level, if opened out to full shaft size, would be inoperative and would serve no useful purpose except, possibly, as a ventilation duct. Original plans therefore did not include continuation of the shaft above No. 4-level. Excavation of a hoist room upon No. 5-level; erection of sheave wheels just below No. 4-level, and a long inclined ropeway leading from the hoist to the sheaves, were incorporated in the general layout. Work on the lower sectionof the shaft had started when the idea of locating the hoist...

Jan 1, 1939

By Curtis G. Kremer

"New explosives initiation systems continue to be developed as new technologies make advancements possible. Due to recent initiator developments, explosives users now have the most reliable, accurate, safest and easy to use systems ever offered. Three initiation systems recentlyintroduced which offer significant improvement over standard electric and nonelectric initiation systems include Magnadet, EXEL high-strength shock tube, and Redundant two-Dath surface delay systems. These three systems will be discussed zn cecail with rmpiasis on their functioning, safety characteristics, ani specific application areas."

Jan 1, 1991

By Antti J. Perala, Teemu J. Yli-Kovero

"Efficient use of land is constantly requiring more underground construction. Minimized execution time and disturbance to surroundings and nearby structures are essential benefits for all construction techniques. To meet the demands of a modern construction project, suppliers have to be able to provide high-quality and tailor-made products just on time. RD pile wall is a retaining wall based on drilled steel pipe piles which are connected to each other with special interlocking profiles. RD pile wall is a solution which enables penetration of overburden soil, dense fill layers including stones and boulders, and embedding into the bedrock in one single operation. Several test installations and laboratory tests have been made to develop the system and to test and improve the water tightness of the wall. Beside these tests, RD pile wall has also proven its reliability in almost 70 projects. Largest project so far has been Pasila Tripla project in Helsinki, Finland. A permanent retaining wall with surface area of 18,000 m2 (193,750 ft2), excavation depth of 21 m (68 ft) and over 17 m (56 ft) of water pressure was made with 711 mm (28”) and 406.4 mm (16”) pile sizes. Piles were delivered to site in one piece with lengths up to 33.5 m (110 ft).INTRODUCTIONExcavations in cramped city centers and in between of existing buildings and other structures are facing more and more challenges. Installation of sheet pile walls is often problematic or even impossible due to obstacles in ground from old structures and due to demand to extend the excavations to even deeper and harder soil layers. Also installations of secant pile walls are facing difficulties due to cramped construction sites and constantly tightening execution times.On the other hand, an efficient and reliable piling technique suitable for the demanding soil conditions described above, percussion drilling, has been developed since the 1960’s, and especially from the mid- 1990’s, when the concentric drilling method with the ring bit and pilot was introduced. A new retaining wall application, the RD pile wall, was developed by combining that drilling method with the widely used retaining wall solution based on steel pipe piles and welded interlocks (a pipe pile wall normally installed with vibratory or impact hammers).PRINCIPLE AND MAIN BENEFITS OF THE METHODRD pile walls can be used in all soil conditions. Most beneficial the system is in extremely demanding soil conditions where the installation of traditional retaining walls is challenging or even impossible. The RD pile wall is a combination of drilled steel pipe piles and interlocking sections as shown in Fig. 1.Individual RD piles are connected to each other with interlocks welded to the piles on the automated welding line at the workshop. The matching dimensions of the drilling system and interlocking sections allow the installation of RD piles through stones and boulders and even into the bedrock, if necessary, in a single operation. Installation is done by a down-the-hole (DTH) hammer using the centric drilling system and oversized ring bits or a drilling system consisting of a pilot bit and reamer wings shown in Fig. 2."

Jan 1, 2017

By Deepak Vidyarthi

This paper deals with various measures adopted in protecting a conveyor duct (named after a Conveyor Belt that was numbered as ‘02’) housing a 1600 mm (63 inches) belt conveyor system in a large, heavily mechanized open cast iron ore mine, producing about 20.0 million tones of ore per annum.

Jan 1, 2008

By M. Drozd, M. Somppi, Z. Yamak

"Granular activated carbon is widely used in the gold mining industry for gold extraction from aurocyanide-containing slurry. The extraction process can employ carbon as part of the gold recovery operation for various circuit designs including carbon-in-pulp (CIP), carbon-in-column (CIC), and carbon-in-leach (CIL) circuits. However, various qualities of activated carbon exist and the durability of the material can change significantly from source to source. Handling this expensive reagent can pose challenges when fine carbon losses occur in the CIP, CIC, and CIL circuits. Additionally, any gold that is adsorbed to these carbon fines can also be lost by various mechanisms including carbon attrition and fracturing, inefficient coarse-fine separation, and poor carbon fines capture. With the above in mind, a series of tests were conducted to investigate standardizing simple laboratory methods for testing carbon quality. A standard procedure beyond or enhancing ASTM methods can serve as additional starting points for evaluating carbon specific to the gold industry. The investigation focused on size distribution, flatness, wet attrition resistance, surface area, gold kinetics, and gold loading. The final results provided information to generate an equation for ranking carbon samples to plant performance.IntroductionActivated carbon for use in gold extraction is amongst the most commonly found processes in modern gold-milling plants. Although gold losses are inevitable in the milling process, operators often focus on the importance of maximizing gold recovery. One focus area that is important in gold recovery is optimizing the use of activated carbon and examining potential changes to realize improved economics for carbon-in-pulp (CIP), carbon-in-column (CIC), and carbon-in-leach (CIL) processes."

Jan 1, 2017

By I Mason, A Wellington, J Hargreaves

Many people are familiar with the use of marine echo sounders which are used by fishermen to monitor water depth and locate schools of fish. Similar technology has recently been used in some West Australian mines to provide detailed maps of ore contacts and other geological structures. Whilst drillhole intersections provide details of the location of a contact at a point, echo sounding can be used to obtain a continuous profile of the contact. A series of profiles together with drillhole intersection data can be used to build a more accurate geological model than can be inferred from drillhole intersections alone. The benefits of this are more complete ore extraction, less dilution and the ability to make more informed financial decisions. This paper presents a case history which demonstrates the successful application of the technology.

Jan 1, 2000

I would like to thank The Australasian Institute of Mining and Metallurgy for inviting us to share with you some of our experiences in the handling, storage, and transportation of industrial minerals in North America. Cometals, Inc. is a wholly-owned subsidiary of Commercial Metals Company, headquartered in Dallas, a public corporation whose shares are traded on the New York Stock Exchange. Sales exceed one billion dollars. Cometals, Inc. is located in New York and specializes in marketing of chemicals as well as raw materials used in the manufacture of steel, refractories, abrasives, glass and ceramics. This makes us one of the larger regular shippers of industrial minerals. Many people are aware that industrial minerals need to be viewed and judged on the merits of their chemical and physical characteristics. In addition you are surely aware that close attention must be paid to the economics of these minerals to determine the appropriate value and competitiveness of the minerals or products delivered at the doorsteps of the consuming work. You may, however, not be aware that the handling and transportation of the mineral is of crucial importance, in fact, the transportation and handling costs of industrial minerals frequently are a major component of the value of the ores marketed and, therefore, it is only natural that close attention should be paid to them. Many of the industrial minerals require special handling to assure that the material reaches the consumer without being contaminated and without getting wet. I invite you to accompany me through the various steps involved in "delivering the goods" to the consumer.

Jan 1, 1989

By Lynn Alcorn, Jeffrey Shawn Peterson

Data collected by the Mine Safety and Health Administration (MSHA) has shown that roof bolting machine (RBM) operators are the second most likely type of underground mining machine operator to be are over exposed to noise, per the MSHA Permissible Exposure Limit. In response to this, the Pittsburgh Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) has initiated a project to develop engineering noise controls for roof bolting machines. Key to this research is an evaluation of the duty cycle of a typical roof bolting machine operation and this paper presents the results of such an exercise for data collected at two cooperating coalmines. The evaluation entails a time motion study of an operators' shift, logging each activity for time (e.g., tramming the machine, drilling holes, installing the roof bolt, etc.) and the noise levels associated with each task with a Larson Davis Spark 705+ dosimeter. NIOSH post processed the data to determine which tasks the operator devotes the most time to and the noise dosage accumulated during those tasks. These results provide insight into which portion of the operators' duty cycle is the most prominent contributor to noise exposure and thus, where research activities for the development of engineering noise controls should be focused. It was determined that the task of drilling holes is the most significant source of the operators' noise exposure and project research has focused on engineering noise controls to reduce the noise emissions generated during the drilling portion of the machine duty cycle.

By P D. "Takis" Katsabanis

The phenomenon of sympathetic detonations in blastholes is investigated by comparing experimental observations and numerical modelling results. Numerical modelling using the TDL computer code and Forest Fire decomposition rates for commercial explosives has shown the importance of blasthole diameter, impedance of the stemming and host rock. Comparison with experimental observations has also shown that sympathetic detonations cannot always be treated as shock to detonation transition. Examination of previous results which have been obtained from calibrated low amplitude shock experiments reveal that there is an ignition threshold prior to the detonation threshold. The difference between the two thresholds is more pronounced in the case of air bubble sensitized products. The ignition threshold can be very important under the confinement provided by the blasthole and the conditions of application. It also correlates well with the pressures expected at the gap distances of interest in the practical application. It is suggested that critical energies are used as the criterion for cross initiation in blastholes. Practical suggestions based on the numerical calculations and experiments based on these calculations are also given and discussed.

Jan 1, 1991

The district specially referred to in this paper comprises the very gently sloping country extending from the western shores of Port Phillip from the mouth of the Yarra to Footscray along the Bacchus Marsh railway to near that town thence in a southerly direction to the Little River, and along that river to the coast, 1 as may be seen on the accompanying map. Almost the whole of this area is covered by volcanic rocks, consisting of pumerous sheets of basalt, which have been poured out of various volcanic hills in the districts, such as Mts. Atkinson and Cotteril, near Melton; Mt. Maryand Bald Hill, 12 and 16 miles respectively N.W. of Werribee; and vents in different parts of the parishes of Tarneit, Mouyong, Mooradoranook, Pyweitjorrk, and Derrimut. These volcanoes were in an active state of eruption during a late period of the earth's historyprobably the late Pliocenll, or still younger Pleistocene.Occupying a narrow strip of country, for most of the distance along the coast from Williamstown to past the mouth of the Little River, there occur deposits of still younger age, belonging to the Recent period. These lie on the basalt, and extend for distances varying from a few chains to more than a mile back from the beach. They comprise superficial deposits of blown sand, and raised beaches, composed of marine sands...

Jan 1, 1902

By Khamis Y. Haramy

Quality assurance and quality control of drilled shafts has become a concern due to difficulties in accurately locating construction anomalies and determining load bearing capacity of defected drilled shafts. Various non-destructive evaluation techniques have been developed to estimate the integrity of the concrete in drilled shafts. While these techniques have been widely accepted, variables and unknowns can affect the measurement results. Results are typically difficult to interpret, leading to unnecessary construction delays and possible litigation over shaft integrity. In addition, influences of surrounding ground materials, stress states under different load conditions, and crack and residual stress development during concrete curing further complicate determination of shaft performance. This paper focuses on the evaluation of load bearing capacity of defected drilled shafts under various conditions by numerical analysis and modeling.

Jan 1, 2007

By Robert M. Valentine, Randall L. Lentell

Interpretive geotechnical investigations were performed for the construction of approximately 15,250 m (50,000 ft) of wastewater interceptor tunnels in Austin, Texas. Subsurface materials consist of claystone (or clay shale), siltstone, altered volcanic tuffs, chalk and limestone. Special conditions include multiple crossings of Onion Creek with cover ranging from about 1/2 to 3 m (2 to 10 ft.), and the potential for mixed-face conditions consisting of water-bearing gravels overlying clay shale or siltstone. The methods and results of the geotechnical investigations are discussed and the inferred construction conditions are compared to those encountered during tunneling. A suggested format is presented for interpretive geotechnical reports for underground construction projects.

Jan 1, 1985

Relatively few longwall mines in the U.S. operate under multiple seam conditions where the two seams are less than 200 ft apart. This paper describes the experience of six that do. These operations are located in PA, WV and UT, and include examples of both undermining and overmining. Some operate above or beneath their own workings, others are in historic mining districts and must contend with abandoned mines that are decades old. The lessons that these mines have learned cover a broad range of topics, including: • Whether to stack gateroads or place them under old gob areas; • How to size pillars and select artificial support to cross longwall stop lines; • How to use yield pillars to minimize multiple seam stresses and coal bump potential, and; • When to anticipate the creation of pathways for gas, water, or oxygen between current and abandoned gobs.