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Transport Canada (Federal Government) constructed the Halifax International Airport (HIA) near Halifax, Nova Scotia, Canada in the late-1950s. Site location criteria were primarily; direct access to the city and a raised flat topography. Unfortunately, the site chosen was located on shallow Meguma group pyritic slate bedrock. In 1982, during the construction of an airport taxiway, it became very apparent that acidic run-off from excavated bedrock at the site was having a negative impact on adjacent aquatic habitat. The ensuing 20 years involved many efforts to rectify the acidic drainage problem with mixed results. Some of the techniques which have been implemented at HIA to address the acid rock drainage (ARD) issue include: dry covers, wet covers, wetlands, electrochemical treatment, open limestone channels, limestone gravel polishing beds, agricultural limestone application, and two hydrated lime [Ca(OH)2] addition treatment plants, the first producing low density sludge and the new one that creates high-density sludge. Based on over 20 years of water quality monitoring data it is apparent that only certain acid drainage mitigation methods have been effective at HIA. In 2000 when the Halifax International Airport Authority (the Authority) took control of the operation and management of the airport, including the ARD issue, it was decided to construct a modern, highdensity sludge, hydrated lime treatment system. This new $CAN 7 million system is now in operation and is achieving compliance with water quality guidelines. Due to high operating cost, a review of methods to optimise the system is being carried out. The HIA ARD problem, though minor by comparison to most mine sites, has provided unique challenges and may provide valuable insights into this urgent environmental and financial issue.

Jan 1, 2003

Sulphide Corporation Pty. Limited operates a Lead/Zinc Smelter at Cockle Creek, some 11 miles from Newcastle, N. S. W . Works effluents totalling some 8, 500, 000 gallons/day join Cockle Creek some 1. 8 miles from its mouth in the most northerly section of Lake Macquarie, The Creek is also the source of the Works cooling water intake of which approximates 8, 000, 000 g.p. d. In view of the wide use of the Lake for recreational activities by the people of Newcastle and the surrounding areas, particular care must be taken to ensure that the control of effluent quality is of a high order. This paper outlines the philosophy and measures taken for the treatment and control of plant effluents discharging into Cockle Creek.

Jan 1, 1971

This is a welcome opportunity to exchange ideas about educating for a profession in mining and metallurgy, and I shall use it to highlight the ways in which educators, the industry, and the profession can help one another make that educa- tion better. This is home ground for me in more ways than one. As the executive head of a uni- versity perhaps I may speak as an educator; and there is still, I hope, enough of the metallurgist in me to allow me to speak of what we metal- lurgists and mining engineers can do to help the educators. Another interest should be declared, too. Among the educating agencies I shall focus on universities; among universities I shall further focus on my own, the University of New South Wales. I know it best; and, more to the point, we are one of the minority that offer a full profes- sional training in mining and metallurgy. Further, we are as a university very much concerned- more than most-with specifically professional education, and especially with education in the professions based on science and technology. Mining and metallurgy have of course played a central role, from earliest times onwards, in the history and development of science and tech- nology. In that role they have been both pro- ducers and consumers of new knowledge. Indeed the whole new attitude to knowledge that began to spread in 16th and 17th century Europe owed a great deal to the interests and traditions of the miner and the metallurgist. The first modern text- book of mining and metallurgy, George Agricola's De Re Metallica, is very much more than a spec- ialist handbook; it is a major landmark in intel- lectual and cultural history.

Jan 1, 1978

By Chung S

The problems associated with equating calculated and measured properties of explosives with blast results are examined. The results from six full-scale test blasts in a limestone quarry are described. The purpose of the full-scale trial was two-fold, i) assess the role of varying aluminum levels (10% maximum) in a given explosive in terms of blasting performance, and, ii) find correlation between calculated, as well as measured properties of explosives and the resulting blasting performance. Each blast consisted of 36 holes, initiated with short period detonators in a staggered 3-row 2.4 m x 2.7 m (burden x spacing) pattern. Each 75 mm diameter borehole with no subgrade contained on the average 22 kg of 65 mm diameter cartridged explosive. The bench height was 6.3 m, with an average collpr of 1.2 m. The calculated and mgasured properties of explosive included, strength, detonation and explosion pressure, VOD, plate-dent depth, underwater bubble and shock energy, and the total energy efficiency. Each blast was instrumented to measure detonation velocity, initiation sequence, muck pile motion by means of high-speed photography and blasting vibrations. The post-blast measurements included photogrammetric survey of muck pile for size distribution on surface, muck pile profile, as well as the extent of backbreak. The results showed that the overall blasting performance of the explosive in question was nearly commensurate with the level of aluminum in the explosive, and there was excellent correlation between the underwater test properties and the blast results. The study also exemplified the need for more extensive post-blast analysis than is usual practice, for quantitative assessment of blasting performance of explosives and providing the necessary data-base for calibration of blasting models.

Jan 1, 1990

By N Trabelsi, D Bakun-Mazor, Y Ben-Ari

As part of a comprehensive project to develop a remote sensing tool for evaluating the mechanical properties of rocks, one must obtain a rapid indication of these properties using conventional field methods. A common method for evaluating the mechanical properties of rocks in the field is to use a Schmidt hammer, a portable device that measures the rebound (R) of a spring-loaded mass impacting against the rock surface. Since the 1960s many studies have been made to find empirical correlations between the R value measured by the Schmidt hammer and mechanical and physical properties such as uniaxial compressive strength (UCS), elastic modulus, density, and porosity. Despite the existing correlations in the literature, this work is required to establish detailed empirical relationships for the carbonate rock units in Israel. To do so, 150 rock samples were collected from 38 different outcrops of carbonate rock units. In each outcrop, 20 impacts were made using a Schmidt hammer at different but adjacent points. The impacts were done horizontally perpendicular to the vertical rock walls. In the laboratory, we measured the density, effective porosity, water absorption, UCS, and elastic modulus. The rock samples we selected contained a wide range of UCS: from 7 to 270 MPa. Our empirical correlations indicate an exponential relationship between R and UCS and the elastic modulus, and linear relationships between R and density, porosity, and water absorbance. The most reliable index is the average of the five maximum impacts out of the 20 made in each rock outcrop. The correlation equations obtained from this work will make it possible to effectively evaluate the mechanical properties of the intact rock in the field, thereby aiding development of advanced tools for rock mass characterisation by means of remote sensing.

Nov 29, 2022

By H Arvidson, V Chamberlain, R Marinho, B Parsons, T Rowl, M Noppé, M Mattera

With the introduction of CRIRSCO (2019) based mineral asset disclosure, Regulation S-K part 1300, 2019 (S-K1300) by the United States (US) Securities and Exchange Commission (SEC), applicable to companies listed on the New York Stock Exchange from 2021, Mineral Resource is now required to be reported Exclusive of Mineral Reserve, referred to here as ‘Exclusive Mineral Resource’ (EMR). EMR is equivalent to reporting Mineral Resource additional to Mineral Reserve, which has been permitted in jurisdictions outside the US for many years. Despite this, there are no practical guidelines in the literature or relevant reporting codes and rules for Competent/Qualified Persons to refer to, which creates a risk that disclosure of EMR estimates across the industry will be inconsistent and potentially ambiguous for analysts, investors, potential investors, and other stakeholders.With the introduction of CRIRSCO (2019) based mineral asset disclosure, Regulation S-K part 1300, 2019 (S-K1300) by the United States (US) Securities and Exchange Commission (SEC), applicable to companies listed on the New York Stock Exchange from 2021, Mineral Resource is now required to be reported Exclusive of Mineral Reserve, referred to here as ‘Exclusive Mineral Resource’ (EMR). EMR is equivalent to reporting Mineral Resource additional to Mineral Reserve, which has been permitted in jurisdictions outside the US for many years. Despite this, there are no practical guidelines in the literature or relevant reporting codes and rules for Competent/Qualified Persons to refer to, which creates a risk that disclosure of EMR estimates across the industry will be inconsistent and potentially ambiguous for analysts, investors, potential investors, and other stakeholders.

May 24, 2023

By Hall C. E, Chrisholm J. M

Resource calculations for shear hosted deposits of any type are difficult regardless of which calculation technique is used. One of the main problems is the determination of the geometry of the mineralisation. Once this has been elucidated then the appropriate resource calculation methodology can be employed with a search distance and orientation that is relevant.

Jan 1, 1993

By L Keeney

Cu-Au porphyry deposits are large tonnage low-grade resources dependent on processing large volumes of material. The ability to understand and predict comminution performance is critical, as it is frequently the rate-limiting step during processing. Parameters required from geometallurgical mapping and modelling of comminution performance are: A×b processing domains based on impact breakage variability, and BMWi processing domains showing grind response variability which lead to Mine throughput domains for a specific comminution circuit configuration. Due to the cost and/or large sample requirements of traditional comminution tests, insufficient data density and distribution of comminution indices commonly exist, making it difficult to model and map deposit scale variability. One method routinely applied to three dimensional domaining is to have an a priori zoning based on geological features (lithology, alteration, mineralogy, textures), and then apply to all material within a given domain the metallurgical values measured on a single sample or average of samples from that domain. The problem with this approach is that commonly the geological domains do not reflect comminution response, therefore compromising the quality of the average domain estimate. To resolve this problem an alternate integrated geometallurgical mapping and modelling method is applied to model and map comminution performance at Cadia East. This paper uses a data set of ~32 000 assay measurements and geological logging information, integrated with ~150 comminution measurements to analyse and develop proxy support models for comminution indices (ie A×b, BMWi, and throughput) based on inherent geological variability. Discrete downhole comminution processing domains are created, mapping orebody response while maintaining inherent variability.

Sep 5, 2011

By D Hope, D Mitchell, B Metcalfe

In recent years there has been a major change among mining companies in their mining methods. This has been driven by the need to increase shareholder value and optimising the value from an operation. With this understanding there has been a need for all producers to become more efficient in their mining processes. An analysis of the coal losses at Mount Thorley Operations indicated that the major losses were in the dragline section of the mine due to coal damage from throw blasting. This damage was evident after the removal of the overburden by the dragline.Coal and Allied Mount Thorley Mine in partnership with Orica Explosives developed a process to reduce the coal loss associated with the throw blasting of Mt Thorley. Orica provided its specialised knowledge and experience in the drilling and blasting area and combined this with the local mining knowledge and expertise of Mount Thorley Operations personnel to conduct the project. This partnership reduced coal loss in excess of 50 per cent whilst maintaining targeted dragline productivity.

Jan 1, 2001

By L B. Sukla, V N. Misra

Microbial desulfurisation of coal has significant advantages over physicochemical desulfurisation processes since the former process selectively removes the inorganic sulfur compounds and heavy metals without significant carbon loss. The purpose of this study was to improve the desulfurisation yield of a coal sample from northeastern coalfields, Assam, India using microbial technique. The coal sample contained 2.13 per cent of total sulfur and 2.59 per cent of ash. Stirred tank reactors of 40 L capacity were operated in batch mode. Initially, the reactor was fed with 40 L of slurry containing ten per cent (w/v) coal, ten per cent (v/v) inoculum of mixed culture of mesophilic acidophiles, native to coal itself and the requisite amounts of constituents for 9K medium without added ferrous sulfate. The percolate of the reactor was then used to seed the medium for the next experiment. The purpose was to obtain a better adapted and more active biomass which would give a better desulfurisation yield for coal. Further studies were conducted in the bioreactor, fed with 40 L of slurry containing ten per cent (w/v) pulp density of coal, ten per cent inoculum (derived from previous studies) and the medium, supplemented with ferrous sulfate. Results showed an increased total desulfurisation yield of 43 per cent in the latter treatment in comparison to the previous one, where the desulfurisation yield was only 23 per cent. The findings also demonstrated the convenience of using inocula derived from coal, where 50 - 60 per cent of pyritic sulfur was removed, while chemical desulfurisation is of little significance with the majority of coal types. The ash content was also reduced to 1.74 per cent as the low pH of the process caused dissolution of a number of common minerals present in the coal.

Jan 1, 2004

In discussing the Asia-Pacific region weare talking about a region which has more than 60% of the world's population, a regional economy which will in 10 years be larger than the European Economic Community, and a group of countries with some of the highest electricity generation growth rates in the world. It is economically the most dynamic region in the world.

Jan 1, 1990

By R Higashi, D Maruoka, T Murakami, Y Iwami

The ironmaking industry consumes a large amount of fossil fuel derived carbon as heat source, reducing agent of iron ores and carburising agent of reduced iron. Although the demand for drastic decrease of carbon dioxide emission, carbon is an essential element for smelting process of molten iron. The carbon recycling ironmaking process by circulating CO has been already proposed to achieve carbon neutrality. However, the production of molten hot metal is not considered in this process because sufficient amount of carbon does not dissolve in reduced iron by CO. Therefore, our group has suggested a new carbon recycling ironmaking process which can produce hot metal. In this process, free carbon and iron carbides produced by carbon deposition reaction using metallic iron as a catalyst are used. It is known that only Fe3C is obtained as iron carbide by using CO gas, however, Fe5C2 is also produced by adding H2 gas. The composite agglomerated with these carbonaceous materials and fine iron ore (Deposited Carbon-Iron oxide Composite: DCIC) is reduced and melted in a furnace. It is reported that Fe3C in DCIC accelerates the reduction reaction and melting of the composite. In this study, the effects of iron carbides and free carbon on the melting behaviour of DCIC are investigated. Fe3C, Fe5C2 and free carbon were produced by vapour deposition using porous iron whiskers and CO-CO2-H2 gas. These were agglomerated with hematite reagent at a certain ratio to prepare DCIC samples with and without Fe5C2. The samples were heated up to 1300°C in inert atmosphere. The DCIC containing Fe5C2 completely melted and iron nuggets were obtained after the experiment. This behaviour was not observed in the composite without Fe5C2. This indicates that using Fe5C2 is more preferable than Fe3C for molten iron production using DCIC.

Jun 19, 2024

By Kister H

Hoesch HUttenwerke AG, Dortmund, West Germany, is an integrated steel work of the Estel-group. The nominal annual production capacity-is about 7 Mio tons of steel. Hoesch has along experience in operation of diffe-rent types of slag granulation plants and of utilization of the granulated product. This experience is used to granulate a large amount of blast furnace slag and to process it in own cement plants and produce blast fur-nace cement.

Jan 1, 1979

By Yu A. B

An experimental study of the packing of a coal heap has been carried out. The bulk density of a coal heap is considered as a function of a number of variables, viz flow rate, conveyor belt speed, the height of the disengagement point of the conveyor belt, coal particle density, moisture content, the size of the heap and coal particle size distribution. The effects of the dimensionless numbers resulting from dimensional analysis on the packing density of a coal heap have been experimentally examined and analysed. Based on the experimental results, equations have been formulated for the estimation of the bulk density of a coal stockpile. The validity of these equations are checked by comparing the predictions with measurements of real industrial Stockpiles.

Jan 1, 1991

With the progress of modern mining engineering, one of the features of which is the mining from greater depths and the hoisting of greatly increased loads, it becomes a matter of increasing importance that the engineer should be able to determinewith some degree of precision the character of the strains on the hauling rope. But a wire rope is a complex structure; it is made up of spirally-twisted strands, which in turn are composed of spirally-twisted wires, and it is not particularly easy to say exactly what happens when this "doubly-twisted structure is wound round a drum or over a pulley.. The difficulty has been generally evaded in ordinary practice by the simple device of adopting a large factor of safety for the rope-usually from 8 to 10-a factor which experience has shown is sufficiently large to cover the bending strains set "up when the rope is passed over pulleys of the sizes commonly considered appropriate.When, however, we add the stress due to the bending of the rope to the stress produced by" the direct pull, we find that the actual factor of safety is usually more nearly 4 than 10, and frequently the bending stresses in the rope are so large compared with the simple tensile stresses that their neglect may easily lead to disastrous results when dealing with problems a little out of the common run. Common Empirical Rules.-It is always "recognized that the bending of a wire rope round too small a pulley is likely to do the rope serious injury, but as it is desirable in ordinary winding operations to reduce the inertia of the moving parts to a minimum...

Jan 1, 1907

This paper contends that optimisation of energy resources through active control and predictive simulation modelling is possible, and that such monitoring leads to large savings in the electricity costs of hot mines (where refrigeration has to be employed). In addition, active monitoring and control can positively affect the establishment of a safe, healthy and productive working environment. In the entire optimisation process certain guidelines were set to ensure that the requirements of the Mine Health and Safety Act were met (South Africa). Varying the quantity of air supplied underground by means of variable speed drive (VSD) fans is one of the crucial factors in the interactive approach towards the optimisation of ventilation, as is refrigeration and the pumping requirements associated with refrigeration. This article highlights the interaction between the amount of air supplied and the effect it has on refrigeration requirements underground. This article also considers the effect that this would have on contaminant control. Various tools are available for ventilation and cooling design for mining. A lot of these tools are based on the assumption of steady state conditions and do not take into account instantaneous changes in conditions, day-to-day, or hour-to-hour (such as for temperature and contaminants). They also do not take into account the optimisation of energy resources related to the creation of the acceptable underground conditions. With these tools worst-case and best-case scenarios are identified, and strategic decisions are made accordingly. Currently, the amount of the fresh air, the velocity of the air, and its general temperature in the mine are only changed when one production phase changes into another (or when unacceptable conditions occur as a result of poor design or neglect). This means that during a specific production phase (which can last for several months), there can be an oversupply, or undersupply, of energy resources, which will obviously affect the concentration levels of the various contaminants (through under or oversupply of air).

Jan 1, 2005

DURING the four years, 1922, 1923, 1924, and 1925, China produced the following quantities of non-ferrous metals and ores: Antimony Products - 67,869 (long) tons. The production for 1925 was 20,869 tons, of which 80% was regulus, 14% crude,and 6% oxide.Arsenic (White) - 4200 tons. The production for 1925 was 1200 tons, but only 90 tons were exported, some 25% of which to Hong-Kong, France, and U.S.A. each, and the rest in small lots to other countries. Domestic consumption was 1110 tons, and thelocal price for "cake" was around £47 per ton on 1925 exchange.Arsenic Ore (Realgar) - 1400 tons.Lead Ore (Galena) - 44,853 tons. The production for 1925 was 10,853 tons, of which 16%, produced in Korea, went to Japan, and 84% produced in Hunan, went to Europe.Manganese Ore (Pyrolusite) - 142,567 tons. The production for 1925 was 42,567 tons, of which 94.3% went to Japan.Tin Ingot - 33,480 tons. In 1925 the exports to Hong-Kong were 8880 tons of usual rough tin of 94% to 96%. Most of this was refined to No. I Chinese quality of 99.3% and exported to U.S.A. and Europe, owing to the good price ruling.Sulphur - 12,000 tons. Sulphur is included in this list in order to explain how its production led to the discovery of some other ores.Wolfram - 19,668 tons. The production in 1925 was 5868 tons, most of which came from the Quee Mee mountain district in South Kiangsi, from the detrital deposits. Civil disturbances prevented the usual output from Hunan border.Zinc Ore (Blende) - 134,190 tons. Exports for 1925 were 34,190 tons of low-grade ore, averaging 30% zinc, 14% lead, and 7% silver...

Jan 1, 1927

By K Rau

The overall success of a mining operation is directly impacted by the reliability and availability of mining equipment. Heavy-duty vehicles such as excavators and haul trucks are used for conveying of bulk material and improving such assets’ availability helps reduce costs, increase throughputs and improve safety (Ravande, 2022). If a mining operation’s key performance indicators (KPIs) are tied to operational performance, then overall equipment effectiveness (OEE) is an essential metric to track progress and to identify areas of improvement.

Sep 1, 2024

By P T. Stoker, A Allman, D P. Carville

Classification of mineral resource estimates is one of the most important responsibilities of the Competent Person. In recent years, classification decisions have been driven more by the detailed block-by-block attributes generated by the now widely applied geostatistical estimation methods, and less by a general geological overview. This is increasingly resulting in æspotted dogÆ outputs, in which blocks of Inferred Resources or unclassified material separate blocks of Measured and/or Indicated Resources, or individual drill holes are surrounded by annuli of Measured and Indicated Resource blocks. Not only are such outputs potentially misleading, since they ignore fundamentals such as continuity of geology and mineralisation between drill holes and the imprecise nature of resource estimation, they can also cause substantial problems for engineers undertaking mine designs and estimating ore reserves, particularly for underground mines. Competent Persons for mineral resources must keep in mind the purpose of their work, and should use their experience and judgement to avoid or smooth out æspotted dogÆ classifications, providing a result commensurate with the level of geological and resource estimation confidence. For their part, ore reserve Competent Persons must understand the resource estimation and classification process, and should question resource classifications that are not consistent with the level of geological and resource estimation confidence.

Jan 1, 2006

By R Dunne, D Yan

In flotation where a bulk flotation concentrate is produced or a gangue sulfide such as pyrite contaminates a concentrate, residual collector has to be removed from the sulfide surfaces to allow selective separation in a subsequent flotation step. Depending on the sulfide mineral, the main species that needs to be removed when using a xanthate collector is either a metal xanthate or dixanthogen. For the identification of surface species, specific solvents may be used to remove each species û metal xanthates are known to be soluble in acetone whilst dixanthogens are known to be soluble in non-polar solvents such as diethyl ether. Xanthates break down with time, temperature and pH into various decomposition products. The major decomposition product is dixanthogen which can aid flotation but other products such as perxanthate and carbon disulfide can have an adverse effect on flotation. Various analytical techniques can be employed to monitor the formation of decomposition products on the surface of the mineral and in solution. The best of these is ultraviolet spectroscopy as it has diagnostic peaks for decomposition product determination. In this work two approaches were taken to understand the relationship between the flotation of a chalcopyrite and pyrite from an ore containing these two minerals. One approach was to remove the xanthate species with an organic solvent and then use ultraviolet spectroscopy to determine the concentration of dissolved species. The second method involved measuring xanthate decomposition in solution by measuring the residual xanthate concentration using ultraviolet spectroscopy. These experiments confirmed the species adsorb at the surface of the mineral and how these species affect the recovery and grade of the valuable mineral. In both cases pH and temperature were varied and two xanthate collectors (SEX and PAX) were used to study these relationships. These relationships could be applied to industrial flotation systems and allow for more accurate determination of optimal xanthate dosage and hence save on reagent costs.

Jan 1, 2005