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The phosphorus content of the banded iron formation (BIF) and of the associated iron ore deposits in the north west of Western Australia is known to vary widely, a fact which has considerable econ~mic significance. Trendall and Blockley (1970) have described the variety of textural appearances of apatite in the Hamersley Group BlF, and suggest that apatite may account for the entire phosphorus content of the unaltered BIF.A preliminary investigation using an M.A.C. electron microprobe analyser has shown that, at least in some iron ores and in partially enriched BIF and associated shales, the phosphorus occurrence is more complicated than this. A suite of samples was examined from one location which covered the entire Dales Gorge Member and some adjoining macrobands in the Mt. McRae shale, together with samples selected for their high phosphorus content, degree of ore enrichment, and position relative to the enrichment zone. Calcium apatite was not observed in any sample of ore from this sequence, despite its ubiquitous occurrence in the BIF. Silicate mineralogy in the enriched regions also differs from that in the BIF, but this change has not yet been studied in detail.The phosphorus content of goethite in one orebody is often high and appears to be in solid solution in the goethite structure. It shows little or no variability on a micro-scale within a grain, except where theremay be a zoned enrichment near boundaries and solution channels. There is also a limited solubility of phosphorus in hematite (the maximum observed by the author is 0·1 per cent P); but where the hematite is martitic (after magnetite) its phosphorus content is always low or zero. In some bands, martitic hematite has been hydrated to goethite, and this also has a very low phosphorus content. Phosphorus was not found in the silica or silicates in the ore, and even when iron enrichment is just beginning, a limited suite of samples from the BIF suggests that the phosphorus content of the chert microbands is almost entirely in the microscopic goethite nuclei (after riebeckite) scattered throughout the chert. The ability of goethite and hematite to accept phosphorus...

Jan 1, 1973

By S. A. Sayed, M. N. M. Ahmed, M. A. Doheim

The performance of a 12.7 cm hydrocyclone was investigated by considering the effect of design variables (diameters of the vortex finder and apex) and operating variables (pressure drop and solids content of the feed) at a medium feed solids concentration of mixed minerals. Cut-size was found to be the most important parameter in hydrocyclone design and operation. The effect of feed pressure in reducing hydrocyclone cut-size is less pronounced at medium feed solids concentration with a mixed mineral feed. The choice of vortex finder diameter and apex diameter becomes more sensitive at medium feed solids concentrations. The effect of feed solids concentration in increasing the cut-size becomes less marked at higher concentrations. Predictions of an empirical model were found to be in good agreement with experimental data. Comparison of results obtained from the model with those predicted by theoretically derived models showed the latter to be more promising, with the turbulent two-phase model giving closer agreement with the experimental data

Apr 1, 1995

By Mitsutaka Hino

The contents of gangue minerals, such as A1203, P205, crystalline water and so forth in the iron ore imported to Japan tend to increase year by year, Though the increments of such gangue contents are approximately 0.1-0.2 mass%, some problems for the blast furnace operation in ironmaking process have already been reported, In order to clarify the mechanism of harmful effect caused by the small increment of gangue minerals, mainly A1203, on the blast furnace operation, the dripping behavior of FetO-CaO-SiO2-AI2O3-MgO slag from the iron funnel, which simulated the micro-porosity in sinter ore, has been observed with the wide range of basicity, Al2O3, FetO and Mgo contents. The effect of MgO on the dripping behavior of slag has been summarized in this paper, It was found that the addition of 2mass% MgO resulted in large increase of hold-up on the most of the conditions. When FetO content was less than 20mass% and the basicity was lower than 0.8, MgO lowered the hold-up even if the slag contained 10mass% Al2O3. Every slag hold-up showed the minimum at the basicity of less than unity on the conditions of constant FetO and A1203 contents. This trend became remarkable when the slag contained 2 mass% MgO.

Jan 1, 2003

By N. M. Can

The effects of microwave treatment on the floatabilities and magnetic susceptibilities of some sulfide minerals, namely, pyrite, chalcopyrite, galena and sphalerite, were studied. Pure mineral samples were prepared in -425+212-µm, -212+106-µm and -106+38-µm size fractions. Microflotation and magnetic separation tests were carried out on the samples after microwave treatment at 600, 950 and 1,300 Watts for 5, 20, 60, 90, 120 and 240 seconds. The maximum temperature values of the samples were measured during the microwave treatment, and possible altera-tions on the mineral surfaces were determined by X-ray diffraction (XRD) analysis. The effects of microwave treatment are discussed based on the result of microflotation and magnetic separation tests. The results revealed that pyrite, chalcopyrite and galena were heated very quickly and that their surface temperatures reached ~700° to 900°C, while the temperature of sphalerite reached only ~130°C. The floatability of pyrite, chalcopyrite and galena were decreased when microwave energy and the duration of treatment were increased, owing to oxidation of the mineral surfaces caused by relatively high temperature. As expected, there was no change in the floatability of sphalerite. The magnetic properties of pyrite and chalcopyrite were improved by the increase in microwave energy and the duration of treatment to such an extent that 90% of the feed separated as magnetic product. But no change was observed in the magnetic properties of galena and sphalerite.

Jan 1, 2007

By D. Eugene Rannels, Sarah E. Dunsmore, Cara Martinez-Williams, Yu-Chen Lee

"Dunsmore, Sarah E., Yu-Chen Lee, Cara Martinez Williams, and D. Eugene Rannels. Synthesis of fibronectin and laminin by type II pulmonary epithelial cells. Am. J. Physiol. 270 (Lung Cell. Mol. Physiol. 14): L215-L223, 1996.Previous investigations demonstrated that type II pulmonary epithelial cells regulate extracellular matrix deposition as a function of time in primary culture. In those studies, the matrix fraction was analyzed as a whole. The present work focused on two components of the type II cell matrix, fibronectin and laminin. These glycoproteins have differing effects on differentiation of type II cells in primary culture. Fibronectin synthesis was quantitated between day 1 and day 6 in the cells, matrix, and medium; laminin synthesis was quantitated only in the cells. Although total fibronectin synthesis was regulated as a function of time in culture, reaching its greatest value on day 2, the average proportion of newly synthesized fibronectin in the cells (35%), medium (50%), and matrix (15%) remained constant over a 6-day interval. Between day 2 and day 6, the relative abundance of fibronectin messenger RNA increased 6.5-fold. Rates of cellular laminin synthesis did not vary with time in culture. These results support a role for differential regulation of fibronectin and laminin synthesis to determine the composition of the type II cell extracellular matrix. INTERACTIONS BETWEEN THE pulmonary epithelium and alveolar basement membrane may play a role in the physiology and pathophysiology of the lung. Pulmonary epithelial cells and the alveolar basement membrane form one component of the blood-gas diffusion barrier. Integrity of this barrier is crucial to normal lung function. Specific domains of alveolar basement membrane components have been proposed to determine localization of type I and type II pulmonary epithelial cells during lung growth and development, as well as during repair of the alveolar surface after injury (13). In the injured lung, the extent of damage to the epithelium and the underlying basement membrane is thought to be a key factor to determine subsequent repair or fibrotic scarring (3)."

Jan 1, 1998

By J Weir

Accurate sampling of slurry streams is extremely important for metallurgical accounting in mining operations, not only for measuring the ore grade from the mine, but also for measuring the recovery of mineral by the mineral processing plant. Accurate sampling is also required for intermediate streams in complex circuits for determining efficiencies of processing units within the plant. As the profitability of the minerals industry is squeezed more with time, greater emphasis is being placed on efficient use of the resource and accountability of the various sections of the mining operations. This has led to increased awareness and interest in obtaining statistically correct sampling across the operations. Accurate sampling is not only required for metallurgical accounting, but is also required for on-line analysis of the slurry streams for elemental analysis and for particle size. Sampling of slurry streams for metallurgical accounting purposes has traditionally been one of the areas of concern in mineral processing plants. In the first instance, the sampler must be designed to comply with the fundamental principles of sampling theory and must provide a representative sample of the slurry stream. In the second instance, the sampler must continue to reliably provide a representative sample, regardless of wear of the equipment or build up of solids with time and other operating issues. To-date the main type of sampler that has been used in mineral processing plants for metallurgical accounting has been the Cross-Cut sampler. These have a cutter that periodically cuts across the full slurry stream. For large flow slurry streams, these are often followed by a secondary and perhaps a tertiary sampler, to reduce the flow-rate or sample, to a manageable size. This paper discusses a new method of sampling slurry streams that has been developed by Thermo Gamma-Metrics, previously known as Amdel Instrumentation. The new samplers overcome many of the problems associated with cross-cut samplers while providing a sample which is representative of the main stream, throughout the life of the sampling system. The sampler is called the SamStat (Sampling Station) and it is now proven in many applications across many countries and mineral processing plants (PGMs, Cu/Au, Pb/Zn, etc).

Jan 1, 2002

By Russell Levens

A strategy for prioritizing mining health and safety research by evaluating the potential for risk reduction through interventions is proposed. Mining has one of the highest incidence rates of injury and disease found in major industries. The main premise of this paper is that often the best opportunities to reduce these rates are not revealed by retrospective analysis of injury and illness data. Instead, a proactive approach is needed that accounts for risks to specific hazards that can be abated by engineering or behavioral interventions. The process proposed here begins with development of prospective interventions. The degree of reduction in risk to be expected from an intervention then is determined from statistics on the mining worker population, the expected degree of success of the intervention, and the expected change in the severity of injuries resulting from the intervention. Three disparate mining health and safety concerns are presented to demonstrate common problems in assessing risks of injury and illness and describe additional data needs. Information on events preceding injuries and illnesses and more detailed demographic data on the mining work force are needed to analyze injury and illness data more precisely. Detailed information on exposure to specific hazards is necessary to evaluate the potential for an intervention to reduce risk of injury or illness.

By D. A. Meyer

The long and arduous process of bringing aggregate produced in Mexico to the Gulf Coast of the United States really began in the 1970s when the first exploratory trips were taken by Vulcan's geologists. It was not until the middle of the 1980s that all of the elements of the project seemed favorable and the largest capital investment in Vulcan's history was given the green light. The history of the project will be covered along with a discussion of the role that market forecasting played in the process. Is this the first of many or a once in a lifetime project? In July 1987, Vulcan and its joint venture partner broke ground in Mexico for a world-class limestone quarry and crushed stone production facility. This project is the largest ever undertaken by Vulcan's Construction Materials Group, with a total cost of over 200 million dollars -a cost shared equally by Vulcan and its joint venture partner, Ingenieros Civiles Associados, or ICA, a diversified Mexican company which is also the largest construction firm in Latin America.

Jan 1, 1995

By J. Currie, J. McManus, R. Chenier

"Cominco Copper Division's Valley Mine is located in the Highland Valley of British Columbia, approximately 275 km by air northeast of Vancouver. The nearest towns are Logan Lake, located IS km to the east and Ashcroft, located about 50 km to the northwest.Preproduction stripping of rock and overburden at the Valley Mine's Lake Zone Pit began in mid-1982 following a decision to discontinue mining in the adjacent Jersey Pit. Equipment and mining methods were carried over from the Bethlehem Copper operations which, with Valley Copper Mines, were merged into Cominco in December 1982.Blasting practices, as carried over from the Bethlehem pits, were designed to provide the fine fragmentation required to meet production requirements using the Bethlehem crusher. However, after mining the first few benches of the Lake Zone Pit, it became apparent that overblasting at the pit limits was causing a number of bench failures, as well as contributing to an over-all reduction of the material strength of the rock mass forming the southwest wall of the pit.With present ultimate pit plans calling for the southwest wall to be as high as 300 m, Valley staff realized that potential slope stability problems should be dealt with as early as possible. This philosophy would enable experimentation on phase pit walls in order to attain the optimum slope angle on the ultimate pit wall.As part of an over-a ll slope stability program, a controlled blasting program was initiated at the Lake Zone Pit in March 1983. In this program, Valley engineering and production staff worked together with Golder Associates in establishing design criteria and evaluating the results. This program resulted in a marked improvement in the soundness of pit walls while maintaining the required degree of fragmentation."

Jan 1, 1985

By A. P. Gize, J. F. W. Bowles, D. J. Vaughan, S. J. Norris

Paper presented at the IAGOD international symposium on mineralization related to mafic and ultramafic rocks held in Orleans, France, 1-3 September 1993. Geological evidence from tropical laterites indicates clearly that platinum group metals are taken into solution and precipitated to form grains larger than those in the source rocks. Platinum and palladium move differentially in the surface environment, with Pt partitioning into soils and eluvial or alluvial deposits while Pd remains more mobile in natural waters. Natural organic acids, particularly humic acid, can interact with platinum-group elements and concentrate them even in areas where their content in rocks is very low. Experimental work has confirmed that Pt and Pd can be taken into solution by humic acid at room temperature and in geologically short time-spans. Solubility and deposition may be controlled by physicochemical conditions, reaction kinetics or an adsorption effect, or there may be two competing reactions, solubilisation assisted by organic matter and a kinetically slower metal precipitation

Apr 1, 1994

By C. P. Haller, S. J. Aresco, R. F. Abernethy

The Bureau of Mines has been active in promoting the purchase of coal for Government use under specifications that define the requirements in terms of heating value of the coal, expressed in British thermal units, and the composition as shown by proximate analyses. To these, when required, are added the ash- softening temperature of ash, the free-swelling index, and the hardgrove grind- ability index. Under most of these specification contracts the bidders guarantee the quality of the coal, and that guaranteed by the successful bidder becomes the standard of his contract. The deliveries are sampled in accordance with instruc- tions issued by the Bureau of Mines; the samples are analyzed in the Bureau laboratory to determine whether the coal is of the quality guaranteed by the con- tractor and, if it is not, a price adjustment is made. Analyses of the delivered coal and tipple samples (samples collected at mine tipples as coal is being loaded into railroad cars or trucks) provide valuable data for use in evaluating future bids. In addition, the continuous sampling of coal as delivered is a check on the practical results obtained in burning the coal. The Government purchased approximately 5-1/4 million tons of coal in fiscal year 1953. In connection with these purchases, the Bureau analyzed 11,435 samples. These are published for the use of Government officials and the public. A series of publications has been completed on coal analyses by States, or, where production is small in any one State, by groups of adjacent States. In addition to analytical data showing composition and quality of coals of the States, the publications con- tain brief descriptions of the geological structure of the coal basins, typical mining conditions in the various districts, the principal economic data of the industry, and the relationship of mine or channel samples to delivered and tipple samples. The present publication covers many States but deals only with the analytical data of the coals. Previous publications in this series are: Bulletin 516, Analyses of Tipple and Delivered Samples of Coal (Collected During the Fiscal Years 1948 to 1950 Inclusive); Report of Investigations 4934, Analyses of Tipple and Delivered Samples of Coal (Collected During the Fiscal Year 1951); Report of In- vestigations 4972, Analyses of Tipple and Delivered Samples of Coal (Collected During the Fiscal Year 1952). Following are the Bureau of Mines technical papers published by States, with their numbers: Alabama, 347; Alaska, 682; Arizona, California, Idaho, Nevada, and Oregon, 696; Arkansas, 416; Colorado, 574; Illinois, 641; Indiana, 417; Iowa, 269 and 706; Kansas, 455; Kentucky, 308 and 652; Maryland, 465; Michigan, North Dakota, South Dakota, and Texas, 700; Missouri, 366; Montana, 529; New Mexico, 569; Ohio 344 (and Bulletin 499); Oklahoma, 411; Pennsylvania Bituminous, 590 (Supplement 645); Pennsylvania Anthracite, 659; Tennessee, 356 and 671; Utah, 345; Virginia, 365 and 656; Washington, 491 (Supplement 618); West Virginia, 405 and 626; and Wyoming, 484.

Jan 1, 1955

By Shuvranshu K. Rout, Anup K. Mandal, Biswajit Das, Manos De

"To adopt new technology advancement in Steel Plant, there is a requirement of shifting of operation process from Coke Wet Quenching (CWQ) to Coke Dry Quenching (CDQ). New CDQ chamber foundation with deep basement and underground conveyor tunnel are to be constructed in an operating plant where heavy foundations and structures are located in close proximity. Furthermore, the existing CWQ system will be in operation during new underground construction and erection. Challenges to deep excavation of tunnel and chamber foundation consist of non-uniform ground condition, prevent washing out of soil from bottom of existing foundations, stability of existing nearby structures, presence of large number of underground utilities, ensuring safe underground workplace to construction resources engaged in new construction work along with project schedule and budget constraints. A combination methods involving use of soil nailing, soil grouting, contiguous bored pile and micro pile had been adopted for protection of excavation sides as well as existing structures. Each side of excavation in different stretches were analysed during design as well as construction stages. The use of combination of all techniques in a single brown field project in context of the nature of site constraints and safety issues made this a unique project.INTRODUCTIONSteel Industry is one of the backbones of industrial growth of any developing country like India. Due to increasing land prices most of the steel plants in India are expanding within their existing plant facilities. In addition to that, there is demand of adoption of new technology for future expansion projects to set new benchmarks with global standards.The property owner had earlier installed a Coke Wet Quenching (CWQ) for their Coke Plant. Now, there is a requirement from process department to proceed with Coke Dry Quenching (CDQ). To facilitate the CDQ within the existing CWQ which will be in operation is the main challenge for the property owner. The second challenge is the limited space for underground construction and subsequent equipment erection within the stipulated time frame.From a geotechnical prospective, the project team had uncertainty and reservations in their mind about the construction methodology. Therefore, the role of three “C”: ‘Consultant’-‘Client’- ‘Contractor’ and their combining brainstorming is essential to freeze a working plan for achieving the goal. In this paper, only the excavation support systems for underground foundation structures have been highlighted in the context of solving geotechnical problems."

Jan 1, 2017

By H. Naghavi, M. Karimi

"In self-aerated flotation machines, the gas rate depends on operational variables (e.g. froth depth and impeller speed), pulp properties (e.g. solid content and viscosity), and reagent addition (e.g. type and concentration of frother). The gas rate has a strong correlation with the flotation performance by influencing the gas dispersion properties and froth retention time. A factorial experimental design was used to study how the gas dispersion properties, the froth retention time, and the flotation performance respond to changes in froth depth and impeller speed (as the most common operational variables). An in-depth understanding of the effects of impeller speed and froth depth on the gas dispersion properties, especially the bubble surface area flux and froth retention time, is necessary to improve operating strategies for self-aerated flotation machines. All experiments were carried out in a 50 m3 selfaerated flotation cell in an iron ore processing plant. The results showed that the froth depth affected the metallurgical performance mostly via changing the froth retention time. The impeller speed had two important impacts on the metallurgical performance via varying both the froth retention time and the bubble surface area flux in the froth and pulp zones, respectively. The interaction effects of the froth depth and impeller speed were also established. This allowed us to develop a strategy for operating selfaerated flotation machines based on varying the froth depth and impeller speed with regard to the cell duty. IntroductionA mechanical flotation machine may be divided into two distinct zones. namely the pulp zone and the froth zone (Goodall and O’Connor, 1989; Yianatos, Bergh, and Cortes, 1998; Rahman, Ata, and Jameson, 2015a, 2015b). The overall flotation recovery, Ro, including the true flotation (particles attached to the bubble lamellae) and entrainment (particles recovered in water held in the bubble plateau boundaries), is a function of the recoveries in the two zones. It is calculated as follows (Dobby, 1984):"

Jul 1, 2019

By G. F. Loughlin

Nearly 55 years have elapsed since the U. S. Geological Survey was organized. During this period the mineral industries have grown from infancy or early childhood to well developed maturity, and some mining industries appear to be declining. Decline in mining is even more conspicuous in certain districts, or even states, than in any mining industry as a whole, and discoveries or developments of important new districts have been very few in recent years. Our reserves of most metals and nonmetals are adequate for many years of normal production, subject to changes in rate of exploitation that may be caused by foreign competition and by changes in technology and market conditions; but the declining production of many districts and the scarcity of important new discoveries to compensate for them is cause for some apprehension. It is likely that future production will depend to a considerable extent on deep exploration and on the thorough examination of places in and adjoining existing districts where significant outcrops are lacking and only apparently insignificant geologic features offer encouraging clues—more so than on the discovery of entirely new districts. Even the possible discovery of new districts, which have escaped the intensive search by the nontechnical prospector, must be dependent on geologic information. There is therefore no need for argument as to the value of geology to the mining industry; and the need of continuing to advance the science. The U. S. Geological Survey's past contributions to mining geology, as expressed in its official reports and other publications, are recognized by Ransome in his historical review of mining geology in the Lindgren volume.' These contributions have helped to form the basis of modern mining geology, which has grown rapidly in the last 25 years. This growth has witnessed the organization and maintenance of geologic staffs by mining companies in several districts, and their detailed work, together with the fact that nearly all of the larger mining districts have

Jan 1, 1935

W. Johnson (Consultant, Adelaide) : Is there any mineralogical evidence of temperature of formation of the amphiboles and other minerals present in the crocidolite veins and country rocks7.N. A. Trueman: I am not aware of any definite evidence of the temperature of formation of these minerals, but am of the opinion that high temperatures would not be present during crystallization.No evidence from the qUl'trtz, magnetite and hematite of formation temperatures is indicated and, as the carbonate is later than the other minerals it does not supply any data either.According to Miyashiro and other workers who have studied the composition and stability of the glaucophaneriebeckite series, minerals of riebeckite composition are stable over a wide range of P, T conditions. Recent work by W. G. Ernst, of the University of California, indicate that, in the presence of an Fe203/Fe304 buffer, riebeckite and crocidolite are more likely to form at low temperatures. The occurrence of riebeckite-crocidolite as authigenic minerals has been reported from several localities.Dr. MacLeod (Geol. Surv. of W. A.): Recent regional mapping by the Geological Survey of Western Australia has revealed a total thickness of at least 30,000 ft for the Proterozoic sediments in the Hamersley Basin. In this succession the asbestos-bearing beds of the Brockman Iron Formation at Wittenoom are overlain by some 20,000 ft of younger sediments and volcanics. With such a thickness of superincumbent material, it seems perfectly valid to involve

Jan 1, 1963

By Luzheng Chen

Pulsating high-gradient magnetic separation (PHGMS) of fine hematite from tailings was studied using a pilot PHGMS separator to investigate the possibility of its application in industry. The results of this investigation indicate that PHGMS is effective for recovering fine hematite from the tailings and greatly improved the separation performance compared with the conventional high-gradient magnetic separation at the same conditions. By applying the pilot separator with a 1-mm rod matrix to a tailings containing 28.76% Fe, a concentrate assaying 54.35% Fe with 35.89% recovery was achieved. It was found that the separation performance of the pilot separator closely correlates with the main pulsating parameters, i.e., pulsating stroke and frequency. It was also found that a change in the wire diameter of the rod matrix from 2 to 1 mm causes a weak drop in concentrate grade but results in a considerable rise in recovery. This finding proves that the improved performance achieved by the pilot separator is attributed to the pulsating of slurry and to the use of a 1-mm rod matrix. When the first commercial SLon-2500 PHGMS separator with a 1-mm rod matrix was applied to recover fine hematite from the tailings, the results duplicated those achieved with the pilot PHGMS separator.

Jan 1, 2009

Early strategic mine planning includes decisions over the organisation of work and workforce accommodation. These decisions involve significant commitments that affect not only employee quality of life but also the impacts and relationships with existing local communities. Strategies for workforce accommodation are characteristically community-based (either as purpose-built company towns or integrated within existing local communities) or commuter (fly-in, fly-out) mine camps. The quality of accommodation underpins the fulfilment, morale and motivation of employees. This is not only relevant to productivity and safety, but also to recruitment and retention, particularly with the current onset of a significant human resources crisis. In the event that communities exist in proximity to a proposed mine then the accommodation strategy selected can influence the value-adding potential for the sustainable development of such communities. This early planning is particularly challenging where mine locations are isolated and/or face significant economic, social and political adversity. This paper draws upon a case study review of five large mining projects implemented in three South American countries, selected to cover a range of scenarios and accommodation strategies. The review aims to advance our understanding of the complexity of the underlying planning issues. Each scenario considered the prevailing environmental, social, economic and political situation, together with the adopted accommodation strategy. The case study review aimed to identify lessons learned and to make recommendations for advancing mineworkersÆ accommodation planning practice.

Jan 1, 2006

By O. K. Mahabadi

The scope of this study is to simulate the behaviour of a layered rock sample under standard laboratory Brazilian Disc test using an innovative combined finite-discrete element method (FEM/DEM) research code. The influence of layering and the direction of loading on the samples behaviour are studied through various layering and loading configurations. A parametric study including the effect of loading rate on the tensile strength of samples has been carried out. This paper demonstrates the suitability of the numerical approach to explicitly model rock deformation and failure.

May 1, 2009

Total mechanisation in the Western district of New South Wales is quite a recent addition to productive methods in that State, for it was only in 1940 that the first colliery was equipped for this method of winning coal. Now almost all mines either are totally mechanised or are planning to get their coal by these means.This marked change in recent years is explained by the salient features of the industry's history. Collieries in New South Wales had generally been subjected to low selling prices forced on them by over-production and severe competition. Little money was available out of profits to purchase machinery, and returns on capital were so poor that inducement to invest money in the industry was nonexistent.The second world war brought price fixing at the already low prices. It was not until the post-war period that there has been any inducement to mechanise.Much credit for mechanisation can be given to the Joint Coal Board, a government body formed in 1948. Pursuing a broad plan for the rejuvenation of the industry, this Board, purchased large quantities of machinery for use in, mines under hire-purchase agreement. These agreements encouraged machine mining, and this fact, together with the ensuing production economies, has improved the financial position of the industry.The Board has also been instrumental in the granting of increases in the fixed price of coal, so that the industry has been given an even greater boost in the direction of mechanisation.

Jan 1, 1954

By V Glenn, P McKenna, H Vickers, P Audet, M J. Gillespie, A Gravina, D R. Mulligan

A requisite corollary of mineral sand mining on North Stradbroake Island (Queensland (Qld), Australia) has been the progressive rehabilitation of post-mined lands for the revegetation of native subtropical Eucalypt communities. Since 2005, rigorous environmental monitoring has been undertaken to verify the annual development of post-rehabilitated sites. From these long-term analyses, a chronosequence of land revegetation (ranging from three to 26 years postrehabilitation) was developed to examine the rehabilitation trajectories of various post-mined sites in relation to proximal undisturbed locations. Here, we identified that some sites may be deviating from the intended natural analogues as evidenced by the opportunistic colonisationand otherwise æinvasiveÆ behaviour of a regionally native species (Black Sheoak - Allocasuarina littoralis), which appear to be displacing the intended Eucalypt varieties. Although it is recognised that the broader data trends correspond to distinct periods of adaptive modifications to the implementation of rehabilitation (ie pre- and post-1995), this analysis focuses on further identifying potential above- and belowground feedback mechanisms underlying these divergent ecological outcomes.CITATION:Audet, P, Gravina, A, Glenn, V, McKenna, P, Vickers, H, Gillespie, M J and Mulligan, D R, 2012. Above/belowground feedback may facilitate and sustain mono-dominance on rehabilitated North Stradbroke Island, in Proceedings Life-of-Mine 2012 , pp 15-24 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012