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By Barbara Rutter, Shonn Kevin McNeil

"This study discusses how a prototype was built to measure the sonic velocity in powdered explosives.The sonic velocity of an explosive is a benchmark to determine if the explosive deflagrates or detonates;however, little work has been done to determine this value for powdered explosives. This paperdiscusses the results of the initial prototyping tests where two known mediums, air and water, were used for validation. The prototype did record the sonic velocity within the known velocity ranges of air and water; however, a few depths did not fall into this range. This prototype could be used for testinggranular materials."

Jan 1, 2017

By O. Moselhi

Material can be seen as the fuel needed to execute the project from inception to completion. Material installed provides good indicators of progress achieved onsite vis-a-vis project schedule performance. It correlates well with the role of the schedule performance index (SPI) of the earned value method (EVM). Material is recognized to have a significant impact on achieved progress for physical completion of project activities. This paper presents a study on the development of material status index (MSI) in support of the EVM. Unlike the SPI, the newly developed index account for the criticality of project activities. This is carried out considering the total float of each activity, percent float (i.e. the ratio of float to activity duration) and the total float of the path on which the activity is located. MSI, can independently and jointly with SPI provide root causes behind problems encountered during project execution. In turn MSI can reveal material related factors behind the performance detected by joint interpretation of the two indices. MSI serves to provide added value in alerting management to take corrective actions. While SPI and MSI may have different values, they can jointly augment and enrich the captured project status based on EVM. To demonstrate the capabilities of the developed MSI method, it is implemented on a case study. The case encompasses the construction schedule of a hydro power station constructed in northern Quebec. Different scenarios are adapted from the real case to demonstrate a set of practical aspects of the developed index. The results generated from the analysis of the case study illustrate the useful features of MSI beyond those of the traditional SPI on two fronts; causation and the considerations of criticalities of actives.

Aug 1, 2013

By D. Bernard

Over the last decades, the wrought aluminum casting industry has made significant progress with regards to process consistency by the introduction of new technologies in the field of liquid metal processing and casting. These technologies, combined with the application of best practices, have led to increases in productivity as well as better process performances and product quality. The competition in the addedvalue aluminum products (by opposition to P1020 production) is, however, very strong and involves players that did not hold a major role five years ago but who are now exerting a strong competitive pressure on our industry even sometimes from far abroad. There are still technical and technological challenges remaining in the different areas of aluminum casting production, amongst which metal pre-treatment, furnace operations, in-line treatment and casting hold a predominant influence. The comprehension of the contribution of each individual process step to the entire process chain is a key element and must be considered in future process optimisations. This paper presents the technological position of the casting industry and tries to highlight areas where further progress can be made.

Jan 1, 2006

By B. Tougas

Recycling of titanium represents an important economic activity due to high cost of the material and the amount of returns of machined parts which represent the bulk of finished titanium products (typical "buy to fly" of 10 in the aeronautic industry). In the present work, the metallurgical quality of 76 mm in diameter and 20 cm ingots poured in coated graphite mold will be assessed against the nature and condition of application of 4 coatings namely aluminum oxide, yttrium oxide, zirconium oxide and zirconium oxide with 4% aluminum oxide. The metallurgical quality has been evaluated in terms of alpha case thickness, microstructure and composition. Microhardness from surface will be assessed against casting conditions. Least square regression analysis have been use to optimize casting conditions.

Jan 1, 2011

By A S. Derrington

High-accuracy, solid-state digital reference barometers have proven to be well suited to conducting underground barometric pressure surveys. The only problem is their expense; at least A$4000 each. For this reason, and because barometric pressure surveys are not a routine undertaking, very few mines have been able to justify the purchase of suitable instruments. The author knows of only three Australian metalliferous mines that own them.However, this may soon change given the recent development of low-cost, mass-produced miniature barometric pressure transducers. These transducers were developed to provide an altimeter function in the latest generation of smartphones. The main purpose of the inbuilt altimeter function is to allow the smartphone to be aware of its altitude when the global positioning system satellite signal is lost.This paper describes a prototype barometer that was constructed using one of the most accurate of the latest generation of piezo-resistive smartphone barometric pressure transducers. The prototype instrument was constructed for less than five per cent of the cost of a commercially available digital reference barometer. The prototype was subsequently tested against a reference barometer at the University of Queensland’s Experimental Mine to verify its accuracy and suitability for measuring pressure differences between underground survey stations.It is expected that the instrument’s low cost will pave the way for barometric pressure surveys to become more commonly used in mines. In turn, the resulting improvement in knowledge of major underground pressure losses should allow mine ventilation officers and engineers to optimise their ventilation systems and potentially reduce overall operating costs.An alternative option would be to use a barometer-equipped smartphone as a survey instrument, provided that its inbuilt barometer module is sufficiently accurate.CITATION:Derrington, A S, 2015. Development of a low-cost instrument for barometric pressure surveys, in Proceedings The Australian Mine Ventilation Conference, pp 331–336 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By D Cliff, K Bailey

Traditionally occupational health and safety (OH&S) has been managed for the direct benefits of reducing injury and illness to workers on mine sites. In the current skill shortage climate it is important to recognise the value that OH&S management can have in assisting mines in minimising their exposure to this issue. In times of skills shortage turnover is high as mines poach personnel from each other. This leads to loss of corporate knowledge and loss in productivity through the need to train new personnel in mine-specific operating procedures. In addition absenteeism can significantly disrupt production as there may be no ready replacements available for key jobs. Pressure will be placed upon workers to remain at work even though they are not completely fit for work, leading to presenteeism and consequently loss in productivity. In addition to the threats to routine operation, the loss of management and professional staff can significantly increase catastrophic risk through loss of experience and corporate knowledge. There is increased pressure to focus on events that occur regularly in the here and the now and underestimate the rare, or unlikely, events.The theme of this paper is that by properly addressing OH&S management at mine sites, companies can minimise their exposure to these problems. Put simplistically, a safe and healthy mine is a sustainable and productive mine. Case studies and relevant literature will be used to support this premise.CITATION:Cliff, D and Bailey, K, 2012. Health, safety and sustainability, in Proceedings International Mine Management 2012, pp 53-58 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

By G. R. McMeekin

"THE TOPIC suggested for my contribution to this Symposium was ""Lead-Zinc Smelting - 40 Years of Pollution Control"". The history of the development of smelting industry at Trail and the control of sulphur dioxide could make quite an interesting historical study. However, in the field of environmental control, the public is not particularly interested in what you did yesterday, but rather what you are doing today and what you are planning to do tomorrow. I can't fault this approach, but because there are some subject lessons that history can demonstrate, I would like to tell enough of the story (under three headings) to bring a focus on matters of contemporary concern in regard to public relations and ecology. The three general headings suggested are: (1) time before the capture of by-product sulphur; (2) the capture of sulphur; and (3) the ecological and public relations conclusions from these."

Jan 1, 1972

By Jie Li, Xinyu Liu, Yan Chen, Linjian Ma, Yasong Wang

Nonlinear time-dependent response analysis of salt cavern under extreme loads in disaster mode is of great importance to the safety and disaster prevention of gas storage group. Uncontrolled blowout is one of the extreme conditions for compressed-air cavern operation. Based on the geological structure of Jintan salt deposit, China, the numerical model of the complete process of water solution, cyclic operation, and internal pressure runaway was developed. The effects of rapid unloading on the stress filed, the progressive failure of surrounding rock, the volume convergence of storage cavern, and the ground subsidence were simulated employing an elasto-viscoplastic damage constitutive equation for rock salt. The results indicate that the damage and failure zones propagate much larger in the mudstone interlayer than in the host salt. The volume of damage and failure zones surrounding salt cavern induced by unloading process is 5~6 times that of cyclic injection and withdrawal process. The average volume convergence rate of salt cavern reaches 0.012%/d~0.013%/d, which is 6~6.5 times that induced by cyclic operation. The ground subsidence exhibits a typical funnel curve. The affected region of ground subsidence due to rapid unloading in the blowout period is about two times the maximum cavern diameters. Furthermore, double cavern analysis reveals that the interaction between adjacent caverns may be ignored so long as the pillar width is larger than two times the maximum cavern diameters.

Jan 1, 2015

By Michael Bauer

Increases in productivity and improvements in mining occupational safety and health are intrinsically linked. Over the past years, the German Hard Coal Mining Industry has been able to accomplish both: an increase in coal production and, at the same time, a significantly reduction of accidents. This success has been achieved by advances in technology, better organization and investment in people. Since 1990 productivity has more than doubled, while the total number of accidents has been reduced by more than 90%. Further development started initially with the mechanisation of the winning and drivage technology. Innovative technology and standardisation of the mining equipment were one reason for the increase in productivity and reduction of the accident rate. Therefore this technical development was not only one important pillar of the TOM model explicated later but also the requirement for the successful development of the other pillars. In addition to further developing this innovative technology it was possible to realise procedural and organisational improvements. As a result, the above achievement is based on implementing the three pillars of the so-called "TOM" model (technology, organization, ?Mensch? = human). To increase safety, improve performance, raise awareness and change of employees? attitude, the following technical and organizational requirements have been introduced: ??New innovative technology and procedures, standardized techniques and better equipment. ??Measures to revise or redefine the organizational structure, processes and systems of work, which were then integrated into the company policy and procedures as a company management tool. ??Personnel measures (investment in people). These include, improving motivation and behaviour, training, communication to raise and to change awareness of safety issues. Success in Occupational Health and Safety is not an automatic or self-regulating process. It needs hard work to make improvements and it must be treated as a recurring cyclic process. As a result of the above, occupational health and safety has become a natural part of daily work in the German Hard Coal Mining Industry. This could only be achieved by the unconditional "commitment" of all managers and employees to the issues, coupled with discipline and responsible action. Further improvements towards the ultimate aim of "zero" accidents are only possible by mutual involvement in implementing the ?TOM? (technology, organization and ?Mensch? human) model.

Aug 1, 2013

By S. P. Holt

The Rush & Brown mine has been one of the most consistent small producers of copper ore in the history of Alaskan mining. Approximately 50,000 tons of ore have been shipped to smelters from the property. Production has been made from two distinct and separate ore bodies of dissimilar types. The Shear Vein deposit has been mined to a depth of 500 feet below the surface without a reduction in the size of the ore shoot or the grade of ore. The Magnetite ore body has been partly mined to a depth of 200 feet below the surface. Because of the favorable production record of the Rush & Brown mine, the present need for copper and the fact that the owners were attempting to place the mine in production, it was deemed advisable to investigate this property under the Strategic Minerals Act of 1939 as a possible source of copper.

Jan 1, 1948

By A. V. Bogdanovich

In diamond ores processing, final waste tailings size, rejected to dump, is one of the most important parameters. On one side, it is necessary to minimize losses of diamonds, whose size exceeds 1 mm, on the other side ? to provide for the plant high throughput and sufficiently low capital and energy costs, which is in greater part connected with disintegration process. Extensive laboratory, pilot-scale and commercial-scale dressability studies of different types of diamond ores have been performed at JSC ?Mekhanobr Engineering? in recent years. With that, special consideration was given to determination of the required ores? disintegration size that would provide for a high recovery of diamonds. In diamond ores processing, in order to exclude breaking of large diamonds, stage disintegration is used with regrinding of light fractions and heavy fraction X-ray fluorescent separation tailings. On account of rather weak bonds of diamonds with enclosing minerals, in crushing and grinding of diamond ores, selective disintegration takes place, with aggregates? breakup along plane surfaces of least bonding, which facilitates liberation of diamonds and their transition to free state. Heavy components losses with different sizes of final dump tailings were studied in processing of large samples. It was established, that in order to almost completely exclude losses of heavy components over 1 mm size, light fractions had to be ground to 2.5-3 mm size, while X-ray fluorescent separation heavy tailings of -15+3 mm size do not contain diamonds larger 1 mm in aggregates, and their regrinding does not increase total recovery of diamonds. On the basis of the conducted studies, relationships regarding heavy components and diamonds losses with respect to diamond ores final disintegration size were obtained, providing for more rational organization of the ores disintegration and processing flow sheet. Keywords: diamond, waste tailings size, disintegration process, recovery of diamonds

Sep 1, 2012

By C te Kloot, Z Liu

Blast performance and the resulting drawpoint condition and volume of oversize has the potential to impact operator safety and mine productivity. Underground measurements showed that approximately 14 per cent of production rings in the Ernest Henry Mine (EHM) sublevel caving (SLC) operation had either overbreak in the brow or left collars. There were also oversize rocks reporting to approximately 30 per cent of drawpoints, which accounted for over 7 per cent of total production and significantly impacted production rates. A series of trials were conducted in 2015–2016 at EHM to test changes to certain charge parameters in an attempt to optimise blasting results and, in particular, reduce oversize and overbreak. The detailed analysis conducted included field observations, hole surveying, blast monitor analysis and blast modelling. There were a total of nine charge parameters tested in the project, which fell into two major categories: energy distribution and inter-hole delay. These were based on observations made in establishing baseline data and those parameters most likely to have a significant impact on overbreak and oversize.Key results from the project included oversize reduction and improved brow conditions when energy distribution was reduced through changing charge lengths in certain holes in the standard charge plan. Similar benefits were also seen when the inter-hole delay between blastholes was reduced from 50 ms to 25 ms. Based on these results both changes were made to the standard production ring charge plan at EHM.Moving forward, the aim is to continue monitoring the results from the changes made on all levels to ensure efficiencies are being realised and sustained. A 3 per cent improvement in oversize as a percentage of total tonnes and improved brow conditions not only has a positive impact on production rates, but removes people from any potentially hazardous situations and contributes to a safer working environment.CITATION:te Kloot, C and Liu, Z, 2017. The evolution of production blasts at Ernest Henry Mine, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 33–38 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By M. J. Coolbaugh

Mining of potash more than 3000 ft beneath the water-bearing sediments in Saskatchewan presented the unique challenge of designing stable mine workings and assuring protection from overhead water in a material that was believed to flow plastically, but whose behavior as a plastic material was not sufficiently known. Under the stress conditions ordinarily encountered in mining most rocks behave as elastic materials; that is, they compress slightly under pressure, and rebound when the pressure is released. Salt and potash, however, are different. Even under the relatively low pressures encountered at shallow depths, these materials become slightly plastic and yield to stress by flowing.* The plastic properties become more pronounced at greater depth and pressure, and the question arises as to whether or not the plastic flow will be rapid enough and exert enough pressure to destroy underground structures or interrupt the mining process.

Jan 5, 1967

By K. Gonçalves

One of Vale?s sponsored research project is aimed at the implementation of a practical scale-up procedure for flotation. In this context, detailed flotation kinetics characterization is of critical importance. This work presents the results of a campaign aimed at characterizing flotation kinetic parameters with respect to particle composition. MLA analysis was carried out for 40 narrow-sized iron ore particles with known flotation time from a controlled flotation kinetic test. The iron ore sample studied (59% hematite and 41% quartz) comes from a mine in the southeast of Brazil and the type of reagents applied are the same as used in the plant. For the reagent conditions tested, the overall rougher concentrate (sink) yielded 79.1%, pure quartz and hematite recoveries to the froth were 56.0% and 4.8%, respectively. The results from the kinetic tests show that the flotation rate of the particles doesn?t vary much (~0.03s-1) with composition and that the fraction of floatable particles in each grade controls the separation action. The results show that the rate of flotation is controlled by transport and that the selectivity is controlled by the fraction of floatable particle of each phase.

Sep 1, 2012

By Rakesh Raghavaraju, Bibhu Mohanty

Prediction of fracture and fragmentation characteristics of a rock mass subjected to dynamic loads, such as in blasting remains a major technical challenge. The present study is aimed at characterizing the shock transmission properties in controlled experiments in small scale in a well-characterized granitic rock, under varying borehole coupling conditions. Single blast-hole tests were conducted in a granitic rock sample of 145 mm (5.7 inches) diameter and height. The boreholes (in two diameters: 6.4 mm (1/4 inch) or 9.5 mm (3/8 inch)) were loaded with detonating cord of varying charge weight (5.3 g/m or 25 grains/ft to 31.8 g/m or 150 grains/ft of PETN). The effect of explosion gas penetration into the target rock was eliminated by inserting a thin-walled copper liner along the borehole wall. Embedded carbon composite resisters were employed at varying distances from the borehole to measure transmitted shock pressure for two coupling conditions (i.e. air and water) at distances of 1x to 9x the borehole diameter. The paper analyzes the decay of shock pressure as a function of distance from the borehole, and its implication on shock-induced fracture properties of the target rock as the first step in predicting fracture and fragmentation behaviour in a well-characterized rock.

By A. E. M. Warner, I. E. Hills, C. L. Harris

Since the late Dr. Keith Brimacombe, et al, performed tests at the now-closed Asarco Tacoma smelter and the Inco Copper Cliff Smelter on Peirce-Smith copper converters almost thirty years ago, many Pyro-metallurgists have investigated using the technology. To the best of the authors knowledge, except for shrouded tuyere technologies using substantial oxygen enrichments, the core idea of using high pressure air injection has not been implemented anywhere in the world. This paper reviews the fundamentals of this technology and summarizes the basic economic considerations. It also presents the circumstances of where and when high-pressure injection might be justified.

Jan 1, 2007

By Gungor Tuncer, Ali Kahriman, Abdulkadir Karadogan, Alper Celtikci, Serdar Celik, Yucel Karakus

This paper presents bench blasting designs based on results of vibrations analysis on test shots organized in an open pit coal mine located near to Soma district at Manisa province in Turkey. There are some structures which can be adversely affected by blasting at the coal mine. The one of the main goals of this study is to perform a preliminary assessment of possible damage effect of ground vibrations induced by blasting at these structures by risk analysis based on ground vibration measurements. During this investigation, the data pairs of scaled distance and particle velocity obtained from the 36 event records belong to 9 test shots were statistically analyzed and a PPV prediction equation specific to this site with 95% prediction line were obtained. And also, this equation was used in the derivation of the practical blasting charts specific to this site as a practical way of predicting the peak particle velocity and maximum charge per delay for future blasting. A risk analysis was performed by using this equation. In the light of this analysis, preliminary blast design model was proposed to be used in this coal mine for overburden excavation.

Jan 1, 2012

By A. Mainza, I. Govender, J. Waters

"The study of the properties of mineral processing suspensions is important in understanding how a circuit might behave. As soon as the predominantly dry ore enters a wet milling stage the ore properties undergo changes as a ‘slurry’ is created. Slurries can be classified in terms of their physical properties (particle density, solids concentration, particle size and size distribution, particle shape), and their flow properties such as rheology. Slurry flow regimes are classified into true homogeneous, pseudo homogeneous, heterogeneous and fully segregated, and only true homogeneous and pseudo homogeneous suspensions can be characterized by their flow structure. A class of the heterogeneous regime are the so-called dense phase or settling slurries - those which result in a clear water surface on standing, although they may approach a pseudo homogeneous state if suspended for a sufficient period of time. They are usually extremely difficult to characterize by their rheological properties alone and the rheological characterization of these slurries has always posed a problem, especially at higher concentrations. Previous rheological studies have focused on the individual concentrator units dealing with milling, classification, pumping, flotation, fine grinding, thickening.In this work an attempt was made to characterize two ore types (copper and a Platreef platinum ore) using a custom built Paterson and Cooke tube rheometer, at concentrations up to 43% by volume. After applying a turbulence correction, results showed Bingham plastic behavior. A conventional vane rheometer was then used to compare the rheological behavior of platinum concentrator streams. A size criteria was used to identify any rheologically dominant streams."

Jan 1, 2014

By Xuejing Xie

Exploration geochemistry for many years has been very effective in searching for mineral deposits covered by residual overburden or blind ore bodies hosted in pre-ore rocks. It has not been as effective discovering ore bodies deeply concealed under various kinds of transported overburden or post-ore sedimentary and volcanic rocks. From the 1980s to 1990s, various types of new geochemical techniques with the ability of deep-penetration through exotic covers have been developed. The concepts and methodology of deeppenetrating geochemistry are evolving from partial extraction and gas surveys prevailing from the 1950s up to now, but there are intrinsic differences. Most of the new deep-penetrating methods are used in detailed surveys to delineate deeply concealed ore bodies which could not be ascertained by conventional geological, geophysical and geochemical surveys. In this sense, the sampling and analytical methods of Nameg and Momeo are described briefly. Experiments of such strategic deep-penetrating geochemical surveys have been carried out in desert, alluvium, steppe and laterite covered terrains in China, Australia and Uzbekstan.

Apr 24, 2001

By A. D. S. Gillies, A. Haghighat

"A study has been undertaken at the Missouri University of Science and Technology (MS&T) limestone Experimental Mine to determine new fans set up and wiring options.to install additional mine ventilation capacity. Selection for main fans has been undertaken according to the mine’s required performance specifications and fan characteristics. Available fans for ventilating the mine are Joy and Alphair axial fans each of 24 kW each and two Spendrup booster fans of 12 kW each. The installation of main mine fans on the surface and underground entails numerous considerations. Design of a ventilation network for the Experimental Mine incorporating surface and booster fans has been accomplished using Ventsim Visual program software. The ventilation network has been separated into two segregated parts. A main surface fan and a booster fan have been used in each segregated part of the network. The mine has had a vane axial Joy fan in place for many years. The Alphair 4800 VAX 1800 full blade adjustable pitch vane axial fan was selected and installed as the other surface fan and eventual replacement for the Joy fan. Main surface fans have been connected individually to booster fans in series. The Alphair main surface fan has been installed vertically. Four different wiring options and related cost estimations for addition of the new main fans to the ventilation network have been considered. The analysis resulted in an innovative steel frame design used to allow the fans, when necessary, to be moved to the side of the shaft so that blast pressures do not damage the blades. INTRODUCTION Main fans are the heart of a mine’s ventilation network and play a key role in supplying required airflow (Haghighat, 2014). The Missouri S&T Experimental Mine has been developed in uniform limestone with few stratigraphic features. The mine floor is approximately horizontal and water drains well. A study has been carried out on MS&T Experimental Mine. Selection of main fans has been undertaken according to the mine’s required performance specifications and fan characteristics. Ventsim Visual computer simulation has been used to assist in design of the ventilation network. Wiring circuits, fan foundations and flexibility have been considered as the three main parameters for surface fan installation at the Experimental Mine. Two surface and two underground wiring options and three surface set up options and related cost estimates for the new surface fan system were investigated. Frequent use of explosives in the mine occurs throughout each year. Flexibility in changing the position of a surface fan is important. A number of options have been considered for the location of a vertical main fan positioned on the upcasting shaft. The mine is used for a variety of purposes and flexibility has a high priority amongst design considerations."

Jan 1, 2015