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By Michael Wieland

The resolving capacity of the thermodynamic work-principal model has been seriously refined over its twelve year history, so a review of the innovations, wrong turns and their rectification is warranted to help future researchers. The work-principal model rests upon the four laws of thermodynamics that drive the universe and relatively few other assumptions: like the removing and imposing of constraints on the quasi-potential to yield trapped minimum key-states that represent the wanted process. The formative research was concerned with the role of ingredient changes, the removal of booster influence and the quench temperature with which to reckon toxic fumes. The transfer of reaction-zone energy as work upon the surrounding rock/water/fixture was not fully rationalized until the notion of reversed-inertial pressure was formulated and determined (for water) with underwater trinitrotoluene (TNT) shots. The rock-water-jelly model incorporated that term into its dynamic pressure formula as a way to represent rock blasts or underwater shots, while the zone of reaction gases remained trapped. The real irreversible thermodynamic process, which yielded the total expansion work, was later complemented with a wholly reversible imaginary process, to form a closed thermodynamic loop, with a remarkable consequence – the determination of the theoretical heave and hence, the undissipated-shock by difference from the total work. With the wholly developed model, it was recently possible to quantify the time retardation of reaction chemistry for non-molecular (mining) explosives, as compared to the rather negligible time-retardation found for the molecular (military) explosives in underwater tests.

Jan 1, 2009

A numerical method for discriminating between replacement and sedimentary processes is applied to a folded stratiform sulphide occurrence. It is shown that numerical treatment of chemical analyses from a single diamond drill hole allowed a rapid assignment of the ore to the syngenetic sedimentary class and thereby enabled a revision of the evaluation program concerned with consequent reduction in costs.

Jan 1, 1973

By Ishwinder Grewal, Michael Fullam

Many factors affect the overall performance of a gravity circuit beyond that of the primary gravity recovery device. It is critical to examine the gravity circuit in its entirety in order to determine the dominant operating variables that affect overall performance. Knelson has developed a mathematical model which has been used to assist in the design of gravity circuits, and in particular, in making accurate predictions of plant scale gravity recovery. More recently, inclusion of recovery by particle size class and additional data from various mine sites and research studies has made the model more robust. The model is now able to predict GRG (gravity-recoverable-gold) recoveries using various devices such as centrifugal concentrators, shaking tables, jigs and flash-flotation within the grinding circuit. The benefits derived by these recent advancements in modeling capability are two-fold; the first is as a tool to assist in circuit design and correct equipment selection and the second is as an analytical tool to help to evaluate and enhance the performance of existing gravity circuits.

Jan 1, 2006

By Daniel I. Carey

Current and potential dragline reclamation usage was evaluated for the U.S. coalfields based on data gathered and analyzed during field surveys, literature reviews and contacts with manufacturers. It was concluded that current wining plans have been adapted to federal and state strip mine and reclamation laws in ways which limit the potential for drag line reclamation systems at active mine sites. At abandoned conventional contour mine sites in steep-sloping areas such as central Appalachia, however, it was found that dragline reclamation systems have great potential application and may be the only practical solution to many reclamation problems. Alternative dragline systems were examined for restoring abandoned sites, and it was concluded that a tower excavator system offered superior characteristics and should be evaluated and developed under field conditions. A testing program was developed to provide a framework for the monitoring and analysis of cost, production and environmental data during a field demonstration of a tower excavator system.

Jan 1, 1981

By Richard Wilson

In the early 1970s, it became a concern that exposure to the mineral fibers associated taconite ore processed in Silver Bay, Minnesota would cause asbestos-related disease including gastrointestinal cancer. At that time data gaps existed which have now been significantly reduced by further research. To further our understanding of the types of airborne fibers in Silver Bay we undertook a geological survey of their source the Peter Mitchell Pit, and found that there are no primary asbestos minerals at a detectable level. However we identified two non-asbestos types of fibrous minerals in very limited geological locales. Air sampling useful for risk assessment was done to determine the type, concentrations and size distribution of the population of airborne fibers around Silver Bay. Approximately 80% of the airborne fibers have elemental compositions consistent with cummingtonite-grunerite and the remaining 20% have elemental compositions in the tremolite-actinolite series. The mean airborne concentration of both fiber types is less than 0.00014 fibers per milliliter that is within the background level reported by the World Health Organization. We calculate the risk of asbestos-related mesothelioma and lung cancer using a variety of different pessimistic assumptions. (i) that all the non-asbestos fibers are as potent as asbestos fibers used in the EPA-IRIS listing for asbestos; with a calculated risk of asbestos-related cancer for environmental exposure at Silver Bay of 1 excess cancer in 28,500 lifetimes (or 35 excess cancers per 1,000,000 lifetimes) and secondly that taconite associated fibers are as potent as chrysotile the least potent form of asbestos. The calculated risk is less than 0.77 excess cancer case in 1,000,000 lifetimes. Finally, we briefly review the epidemiology studies of grunerite asbestos (amosite) focusing on the exposure conditions associated with increased risk of human mesothelioma. © 2008 Elsevier Inc. All rights reserved. Keywords: Risk; Fibers; Particles; Taconite; Asbestos; Exposures

Jan 1, 2007

By K Prendergast, P Dale, I Taylor, A J. Vigar, B Lueck

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Kainantu Project is located within the New Guinea Thrust Belt in northern Papua New Guinea. The area has a long history of exploration and production, with the discovery of alluvial gold in 1928 followed by the discovery of vein deposits of gold and copper at Kora in the 1950s and the current Irumafimpa vein gold mine. Current resources on the Kora-Irumafimpa Vein System (KIVS) stand at 1.5 Moz Au, 5 Moz Ag and 217 Mlb Cu.Mineralisation in the region includes gold, silver and copper associated with mid-Miocene age mafic to felsic intrusions. The KIVS occupies a broad north-west-trending mineralised zone more than 2.5 km long and 200 m wide, with the Kora, Eutompi and Irumafimpa veins on the western side and the Judd and Upper Kora veins on the eastern side. Economic mineralisation occurs in two closely related events occupying the same strongly structurally controlled shearing (quartz-Au-telluride veins and sulfide Au-Cu-Ag veins with free Au) and is best described as a significant intrusion-related event with both epithermal and mesothermal facets that does not appear directly related to known porphyry Cu-Au systems as seen at the surface. Significant wolframite is associated with vein quartz of a slightly older age but also occupies the same shear system.The KIVS occurs within a larger mineralised area of approximately 5 × 5 km. It has complex multiphase intrusions, breccias and diatremes that are only partly delineated by drilling and comprises multiple occurrences of Au-bearing veins and porphyry Cu-Au mineralisation. The area is considered to have high potential for extending the current resources and is being actively explored. The proposed recommencement of mining activities recognises the complexity of the KIVS and later disruptive faulting and will require tighter grade control systems, targeted mining techniques and a gravity circuit to maximise free Au recovery.CITATION:Vigar, A J, Lueck, B, Taylor, I, Prendergast, K and Dale, P, 2015. Kainantu gold-copper system, Papua New Guinea, in Proceedings PACRIM 2015 Congress, pp 601–606 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By T. Mal

A test system was developed at the National Institute for Occupational Safety and Health's ventilation test gallery for measuring airflow using a three-axis ultrasonic anemometer. The gallery war used to simulate face airflow conditions in underground mines having a blowing curtain. Airflow data, collected at multiple sampling locations between the face and the end of the curtain, were used to draw airflow profiles for different curtain setback distances, intake flow quantities and entry widths. In addition, methane was released at the face, measured at the sampling locations and displayed as methane distributions in the area between the curtain and the face. Entry geometry had a significant effect on airflow patterns, and the flow patterns affected the distribution of methane in the entry. Flow measured at and parallel to the face was a good predictor of methane dilution and removal within 0.6 m (2ft) of the face.

By Robert J. Maron, Mark Fernald, Alex Van der Spek, O’Keefe. Christian, Tim Bailey

"Sonar array-based non-invasive flow measurement technology is becoming an accepted and many times a preferred method of measuring challenging single and multi-phase flows in the mineral processing industry. This fundamental sensor and measurement technology has been extended to two developments that provide new measurement capabilities useful for monitoring and managing slurry flows and pipes.The first development is the non-invasive measurement of real-time velocity profile of slurry flow in horizontal pipes. Multiple non-invasive passive sensors measure localized velocities and are combined to provide a velocity profile measurement. This information can be used to determine the approach and onset of solid deposition on the bottom of the pipe. Having this information in real time can enable operation at lower velocities and/or higher solids concentration while avoiding solids deposition or plugging and its associated operational costs.The second development is the non-invasive measurement of pipe wear on slurry lines. Presently, such measurements are made by hand-held portable ultrasonic thickness gages. The numerous shortfalls associated with the manual method are overcome with a set of permanently or semi-permanently installed transducers clamped onto the outside of the pipe. This ring of sensors contains a series of conformable ultrasonic transducers spaced around the circumference, which are used to measure the thickness of the pipe under their respective locations. Compared to manual methods, this system and approach results in better repeatability and accuracy. It also decreases inspection labor costs and pipe access requirements. The minimal accuracy variations in the presence of varying environmental temperatures will be shown. Trending of pipe wall thicknesses in high wear pipelines will be illustrated. The benefits of significantly improved pipe wear monitoring in hydrotransport lines with abrasive solids, and associated improvement in the ability to insure safe operation and avoidance of costly environmental damage due to leaks caused by pipe wear will be discussed."

Jan 1, 2009

By J. G. Pippenger

Rio Tinto Coal Australia (RTCA) developed the Meandu Mine in Queensland, Australia in 1983 to supply thermal coal to the adjacent and newly constructed Tarong Power Station (TPS). In designing the mine, RTCA selected Meandu?s best economic reserves for a 27-year life based on station owner Tarong Energy Corp.?s (TECs) estimated life for TPS. That 27-year plan changed dramatically in the early 2000s when TEC approved life extensions to TPS?s four existing units plus construction of a fifth unit. After reviewing Meandu?s remaining reserves, RTCA decided the nearby Kunioon reserve offered the more economic option for maintaining deliveries beyond 2010. Those plans changed again in 2007 when TEC chose to purchase the Meandu Mine and nearby reserves. TEC then selected Thiess Pty Ltd. (Thiess) to continue operating Meandu until the new mine at Kunioon could be developed. After assuming operation of the mine in 2008, Thiess began a review of Meandu?s remaining reserves and found considerable coal available with economic potential. Working jointly with TEC, Thiess performed several analyses on Meandu and subsequently the Kunioon coal reserves. The results changed TEC?s decision from expediting Kunioon?s construction to instead continuing Meandu?s operation for up to 15 additional years.

Jan 1, 2011

By I. Nikolic

Twin-roll casting is an integrated casting and rolling process that involves the continuous solidification of a melt and the plastic deformation of the solidified metal between two rotating rolls. Computer modeling is a valuable tool to help engineers understand the metallurgical process during twin-roll casting. However, commercially available software can only model either the fluid flow/heat transfer of the melt or the plastic deformation of the solid, but not both. In this study, an object-oriented finite element program was developed to simulate the steady-state fluid flow, solidification and plastic deformation of an A7,31 magnesium alloy in a horizontal twin-roll caster. The melt, the mush zone and the solid were treated as a generalized Newtonian flow in an Eulerian reference frame and different constitutive equations were employed to describe the material behaviours. The effect of operational parameters on the solidification process was discussed based on the simulation results.

Jan 1, 2010

Application of Discrete Element Method for Simulating Feeding Conditions and Size Reduction in Cone Crushers

Sep 13, 2010

Two outstanding features of the world's young orogenic belts are their very consistently developed suites of volcanic rocks and, it is now recognized, the rather distinctive types of mineralization they contain. Further,it is now known that these volcanic suites exhibit evolutionary patterns, and it is beginning to appear that this evolution in style of igneous activity is accompanied by a parallel evolution in style of mineralization. Specifically,podiform chromite and stratiform pyritic copper ores of Alpine ultramafic/submarine tholeiite association progressively give way to more zincian stratiform ores associated with andesites and dacites, "porphyry copper"deposits developed in quartz dioritic to dacitic plugs, and lead-zinc stratiform ores related to increasingly pyroclastic, rbyodacitic volcanism.This "coupling" is exhibited well in the volcanic arcs - the young orogenic zones-of the SW Pacific which, with tbeir abundance of youthful and commonly unmetamorphosed materials provide an opportunity for investigating, through a petrochemical approach, the possible significance of ores in the elucidation of mechanisms of lava formation. It is suggested as a working hypothesis that in the orogenic (voleanic arc) regime ores are associated with the cale-alkaline rocks because these cale-alkaline rocks are in part generated by exhalative loss, and the ores are among the manifestations of tbat loss.

Jan 1, 1978

By P G. Rutherford, A W. McOnie

A volcanic sequence is described from the Golden Cross Mine, Waihi, New Zealand. The sequence includes seven lithostratigraphic units comprising flow and pyroclastic units of Coromandel Group andesite and dacite and overlying Whitianga Group dacite and rhyolite which is intruded by the Golden Cross dacite porphyry and rhyolite dykes. The sequence is mineralised and is unconformably overlain by two post-mineral units, the lacustrine Waitekauri beds and Omahine Subgroup andesite.   Detailed structural analysis of mine data has identified four deformational events (D 1-D4) and related these to the gold-silver mineralising events. Faulting was coeval with the mineralization and directly controlled the development, localisation, style and geometry of the ore shoots. Mineralization developed in competent lithologies where dilation occurred during faulting. The Empire Fault is the master shear which controlled fluid flow. Mineralised veining developed in response to tectonic pulses occurring at slightly different stages as represented by the underground Empire vein complex and the open pit vein array. The mineralising events culminated with the deposition of barren calcite veins. Post-mineral movement along the Western Boundary fault appears to have offset the orebody.

Jan 1, 1995

Fragmentation Characteristics of Iron Ores from Anshan, China

Sep 13, 2010

CONTENTSIntroductionNorthern ExplorationDrive ConceptionGeneralDriving CrewDrive Cross Section and Track DetailsVentilation by Electrically Driven FanTemperatures and HumidityFan PerformanceRock Drill Carriage and Rock DrillsStandard Drilling RoundElectric Firing from Power MainsExplosives and DetonatorsCharging and FiringMechanical Loading and Electric HaulageOperating CycleStatisticalEquipmentAcknowledgementINTRODUCTION.The driving project described in :this paper is one of greater magnitude than usual for the Broken Hill field, and in the execution of the work a departure was made from long-established local practice by the introduction of mechanisation. The primary object of the drive is to provide sites for gaining information regarding the behaviour of the ore-bodies well beyond the limits of the present exposures.Due to thermal conditions, the major portion of the work was done on a six-hour shift basis, in contrast to the normal one of seven hours, with a five-day week.

Jan 1, 1946

To meet the energy requirements, hydroelectric projects are planned and executed in many countries. Though these projects requires a high capital investment, the returns are regular with minimum maintenance after commissioning of the project and are ecofriendly. Bhutan is situated in the eastern Himalayas and covers an area of 38,394km2 (14824.01sq. miles. It is bordered by India in East, South and West and by Tibet in the North. The hydropower potential of the country is estimated at 30,000MW, out of which around 5% has been harnessed.

Jan 1, 2016

By J. C. Johnson

High-grade ore found in a shaft pillar at the Homestake Mine prompted a request for a Bureau of Mines study to determine if selected areas of the shaft pillar could be mined without jeopardizing the shaft. The design approach was to perform a finite-element study of the shaft pillar. Plan view and vertical sections were developed using two-dimensional, elastic, plane strain assumptions. Input into the model consisted of in situ stress measurements geologic mapping rock mass properties, and previous mining history. Results from the study indicated that ore-beating sections of the shaft pillar could be removed within the displacement tolerances acceptable for the shaft. Homestake engineers, using the results of the finite-element study and considering other factors, have designed and are beginning to mine the shaft pillar.

Jan 1, 1989

By K. Hanson

When done properly, benchmarking is an extremely effective tool for assessing ones performance, finding areas for improvement, and identifying strengths. However, when done improperly it can be an exercise in futility and result in incorrect observations and conclusions. A primary pitfall of benchmarking is collecting too much unreliable information. Surprisingly, the evolution of data storage and the ease of data collection are not helping with better data collection. Instead, it is just allowing one to collect more information, while at the same time inundating one with too much data. Additionally, the process of data collection can be tedious and is often times delegated to the least experienced individual resulting in unreliable and incorrect data collection and entry. Another primary pitfall of benchmarking is metrics that are cost based or poorly designed. Cost based metrics typically involve comparing unit mining costs ($/tonne). Between mines, unit mining costs are not very well correlated and have become further complicated by significant regional cost variations and mining inflation in the last years. Likewise, poorly designed metrics lead to poor benchmarking results. Examples of poorly defined metrics include: metrics that rely on information that is difficult to collect, metrics that are poorly defined, metrics which are too site focused, and metrics that measure low consequence practices.

Jan 1, 2011

By Frederick W. Slack

This paper will discuss the inherent value engineering associated with the design and construction of approximately 184,000 SF of anchored tieback wall, installed as part of the widening and drainage improvements for KY9 in Campbell County, Kentucky. The total project is 2.2 miles in length. The anchored walls, excavation grading and drainage total to a complete project cost of $28.4 million. This is one of the largest design-build projects undertaken by the Commonwealth of Kentucky. It also features another first for the Transportation Cabinet - the general contractor is responsible for quality control/quality assurance. The project is located just south of Cincinnati, OH and is situated along the east bank of the Licking River. The slopes along this stretch of the river have had a long history of movement and instability. The Kentucky Transportation Cabinet advertised the anchored wall portion of this project to be designed and constructed by pre-approved specialty contractors. The Transportation Cabinet provided the basic design parameters to each specialty contractor. Aspects to be discussed include the site and project history, previous attempts at slope stabilization along existing KY9, the technical proposal and bidding process, and the actual design and construction.

Jan 1, 2003

By Richard E. Danell

"Blasting is a principal step in the surface mining process for breaking and, in the case of overburdencasting, moving rocks and minerals. As many surface mines are coming to the end of theiroperational life, blasting can once again play an important role through the earthmoving operationsrequired to rehabilitate the minesite. Since blasting is such an energetic and destructive process, itis difficult initially to envisage its use in rehabilitation. However, blasting has found applications inmany civil engineering projects aimed at rehabilitation, including well digging, channelling and soilcompaction. For surface mine rehabilitation, the main purpose of earthmoving operations is toproduce a stable landfonn that will sustain revegetation. In particular, blasting can be applied toreducing the slope of steep walls left by quarrying and open pit mining through a modified form ofthe overburden casting technique. Blasting can also be applied to breaking up pit floors andbenches to speed and improve revegetation of these areas (subsoiling)."

Jan 1, 1994