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By AMIRA P588 Research Team

This contribution summarises new knowledge and data, obtained during a three year ARCAMIRA funded research project, on the mineralogical and geochemical characteristics of hydrothermal alteration associated with low sulfidation, gold-silver epithermal deposits. These data are used to develop exploration vectors for use at both deposit and district scales, plus techniques have been established to distinguish ore grade epithermal systems from barren or low grade systems. Deposits investigated were Ladolam, Papua New Guinea, Gosowong and Mt Muro, Indonesia, Cerro Vaguardia, Argentina and Bimurra and Twin Hills, Australia.

Jan 1, 2005

Author's Note: Since the paper on "All-Flotation at North Broken Hill Limited" was read and discussed, the metallurgical results obtained have conclusively justified the adoption of the All-Flotation treatment.At present the shipping grades of lead concentrate produced from North mine ore range between 74% and 75% Pb, carrying approximately 43 oz. Ag and 4.5%-5% Zn. The lead recovery in lead concentrate is recording 95%-96% of the lead content of crude ore, and the milling and treatment cost on 6400 tons crude ore perweek of 96 hours has dropped to 6s. 3.6d. per ton on ore. With an increased ore tonnage, and with a new mill, considerable further reduction in costs is certain.New flotation machines, with 30 in. vertical depth of overflow (instead of 42 in. depth), are now being tried for the secondary granular treatment, with advantageous results. The treatment to-day is practically the same as that outlined in the paper, excepting that additional concentrate is returned for retreatment in the existing units.(Signed) A. LOWRY.Mr. T. A. READ: The author states (page 356 of Proceedings, No. 79), "The sulphide ore itself was then comparatively coarsegrained, a fact which permitted ready concentration of the galena contents by means of jigs, tables, vanners, etc."

Jan 1, 1931

The ultraviolet spectrum of isopropyl ethylthionocarbamate (the principal constituent of Dow flotation collector Z-200) in water and of Z-200 itself in water was found to have an absorption peak at 242 nanometers(nm). The height of this peak was found to be directly proportional to isopropyl ethylthionocarbamate concentrations up to 15 p.p.m. Z-200 contains about 90 per cent isopropyl ethylthionocarbamate and the heightof the peak was proportionately lower, but obeyed the straight line relationship up to 15 p.p.m. This showed the potential value of spectrophotometric measurements for the determination of Z-200 residuals in flotation liquors.Methyl ethyldithiocarbamate (an impurity in Z-200) increased the peak height slightly, but other impurities in Z-200, xanthates, and most inorganic salts present in flotation liquors do not interfere. However nitrate ion and thiosulphate ion have absorption peaks which overlap the isopropyl ethylthionocarbamate peak.The simplest general method to overcome this effect is to extract the isopropyl ethylthionocarbamate into cyclohexane and to measure the absorbance of the extract.The maximum absorbance of the cydohexane extract was at 247 nm and the peak height at this wavelength was found to be directly proportional to the isopropyl ethylthionocarbamate or Z-200 concentration in the original aqueous solution. An alternative method is to measure the spectrum of the original aqueous solution using the aqueous raffinate from extraction as a reference solution. This gives the spectrum due to isopropyl ethylthionocarbamate alone and measurement of the absorbance at 242 nm gives the concentration in the original aqueous solution. Both methods give the same value for the concentration of isopropyl ethylthionocarbamate in the original solution.

Jan 1, 1969

Copper mineralization associated with minor molybdenum, silver, and gold occurs in a hydrothermally altered brecda within a granodiorite mass of Upper Permian age. A dyke system of rhyolite, dacite, and andesite forms plug-like bulges near the breccia and probably caused mineralization as a late stage effect.Base metal sulphides occur as disseminations, fracture and cavity fillings in the breccia. A pyritic halo in hydrothermally altered granodiorite surrounds the breccia and grades into unaltered granodiorite. Drilling during 1969 indicated the grade is subeconomic.

Jan 1, 1972

By J T. Woodcock, G J. Sparrow

A sample of pyrrhotite flotation concentrate pulp assaying 15.3 g/t Au, which had been prepared from an old tailing dump, was treated to extract the gold. Examination of the concentrate with an SEM showed that exposed or free native gold, 5- 40 ¦m in diameter, was present but no locked gold was observed. Direct cyanidation of the concentrate to extract the gold showed that the flotation reagents present inhibited gold extraction. A range of pre-treatments was used to overcome these effects. Direct cyanidation for 48 h extracted only 26 per cent of the gold, indicating possible contamination of the gold in the concentrate with flotation reagents. Pre-treatment of the concentrate pulp by aeration for 24 h, or by 72 h aeration with an addition of 3.65 kg/t of sodium sulphite, gave little improvement in gold extraction by subsequent cyanidation. Pre-treatment by filtration, or by aeration with 12.5 L/t 100 volume hydrogen peroxide, followed by cyanidation for 48 h gave gold extractions in the range 67-77 per cent. Combining filtration and an aeration period with hydrogen peroxide addition raised the subsequent cyanidation extraction of gold to 88 per cent, giving a tailing assaying 1.5 g/t Au. Re-cyanidation of some of the dried tailings from the initial tests extracted most of the remaining gold giving a tailing assaying 0.5 g/t Au. This indicated that most of the gold was available for dissolution by cyanide. The poor dissolution of gold by cyanidation of the untreated concentrate was attributed to the presence of flotation reagents. It was shown by UV spectrometry that xanthate-containing compounds were present in the solids fraction of the original pulp and that they were partly removed by pre-treatment. MIBC was also present, and dithiophosphate, which was used in the flotation step, was also probably present. The results indicated that the improvement in gold extraction after filtration and oxidation of the original pulp was due to partial removal of the flotation reagents, and illustrates the detrimental effects that residual flotation reagents can have on the extraction of gold by cyanidation of a flotation concentration.

Jan 1, 1990

Triboelectric Charge and Separation Characteristics of Industrial Minerals The basic principles of triboelectric charge and separation of minerals and the factors affecting the entity of the charges developed on mineral surfaces are discussed and the surface pretreatment methods by which the electrophysical properties and thereby triboelectric charging and separation of minerals can be artificially altered/modified are reviewed. Furthermore, the triboelectricfication theory of materials is envisaged from the chemical concept of acid-base donor-acceptor and an attempt is made to correlate the physical concept of triboelectrification with the donor-acceptor properties. The triboelectric charge characteristics of the quartz, calcite and wollastonite mineral samples for different size classes were defined using different tribocharging medium. Based on the triboelectric charges acquired by mineral samples their energetic work function values are estimated. In addition, the main electrophysical properties, ie dielectric constant and electrical conductivity, of different size fractions of the mineral samples are measured and their donor-acceptor chemical properties were defined. A series of triboelectric separation tests were conducted to explore the possibilities for separation these mineral from each others. The results from the triboelectric charge and separation of the single mineral systems showed promising prospect in separating quartz, calcite, and wollastonite from each others. Finally, attempts were made to explore the possibilities to implement triboelectric charge and separation process to real ores. Promising results achieved when separation of calcite from silicate impurity was sought from a carbonate ore. A very high purity (99 per cent) calcite product was obtained at a recovery of 80 per cent. Interesting results were also achieved to concentrate wollastonite from a complex silicate ore containing quartz, different feldspars, wollastonite and other Mg-Fe silicates. In this case conditioning of the ore with salicylic acid at defined temperature and relative humidity was found to be essential to concentrate wollastonite. The outcomes indicate despite the fact that triboelectric charge and separation process has not been completely perceived, it pronounced to be an environmentally friendly and economically viable technique for minerals and wastes beneficiation. Being a dry beneficiation technique the process has special appeal, which must be explored further in particular for treating industrial minerals.

Sep 13, 2010

By D Bruce

OZ Minerals’ Carrapateena mine is a Sublevel cave mine located in South Australia, approximately 160 km north of the regional centre of Port Augusta. Carrapateena commenced underground development in 2016, with production commencing in 2019 and ramping up to 4.25 Mtpa by December 2020. In pursuit of continual improvement, the Carrapateena mining team sought to identify how it could better interrogate its current productivity levels and its drivers (root causes). During this process the team were confronted by a disconcerting number of different opinions (which often conflicted) on our actual productivity performance which led to a need for review. Although reliable data and a well-designed time utilisation model (TUM) existed, it was still unclear what actions needed to be put in place to improve productivity. This was for the following reasons: • Data sources were disparate unless significant effort was applied to compile them. • Data sources were not available in a format that could be easily viewed or analysed. • General understanding of the data which was collected and how it could be used was poor. • Process of regularly analysing performance and forming tangible actions to improve was lacking rigour. A project was then started with the goal to fix the areas stated above. An initial requirements gathering exercise was undertaken to identify key data sources for site which returned a staggering 42 known systems which were then shortlisted to the key systems that contained operational data and could generate tangible improvements when analysed. This paper discusses the approach to selecting the OZ Minerals Insights Hub as the chosen platform, and the effort and collaboration between cross-functional departments that was involved in transforming the data so it could be displayed in a useful way. The data sources identified included a fleet management system, two planning databases, a control system historian, and a mobile fleet machine data system. New processes were also introduced to digitally capture daily commentary; this was achieved utilising SharePoint Forms. Data pipelines were then developed in the Insights Hub platform to automate the ingestion and transformation of the raw mining data into curated data models for end user consumption. Tableau dashboard packages have been created to support facilitation of short interval control, daily review meetings, and weekly review meetings as well as data analysis of key equipment and locations. These dashboards visualise the mining data models in a form that provides the user a clear picture of what has occurred, why it has occurred, and where to focus improvement efforts. This has resulted in a team which is more accountable, more equipped to assess the root cause of performance, and more regularly able to make data driven decisions. The next step? To build this out from Mine to Mill and create a data indexing tool which will drive self-service reporting, a data agnostic platform and predictive tools that help our people continue to be one step in front.

Mar 29, 2023

As this is the first occasion I have had, and probably will be the only opportunity I shall have, of addressing such a large gathering of members and of student members of the Institute, I desire to- express my very deep appreciation of the honour 'you have paid me in electing me to the office of President for the current year. I realise also that such selection is a tribute to the Company which controls operations here, the centre selected for the annual meeting, but nevertheless there is afforded to the recipient a great deal of pride and of pleasure to hold the highest office in what is, in my opinion, undoubtedly the most important engineering society in Australasia.The past year has witnessed an unprecedented and unparalleled event in the history of the British Empire, and I think that we must all feel a wonderful sense of proud patriotism; the whole world was forced to admire the public calm and the dignity which accompanied the change in our Sovereign Ruler, and great tribute is due to the statesmanship of the Prime Minister, Mr. Baldwin. At this time, we should, I think, place on record our prayer, in common with all his people, that His Majesty, King George the Sixth, may enjoy a long and prosperous reign.The meeting at Port Pirie recalls one who did so much for the advancement of mining and metallurgy, especially in Australia. I refer to the late Mr. Delprat, who, as General Manager of The Broken Hill Proprietary Company Limited, had under his control for many years the smeltery in this centre. As you are aware, he had been elected an honorary member of this Institute, as well as of our sister Institutes in England and in America...

Jan 1, 1937

At the treatment plant of the Broken Hill South Limited, Broken Hill, the zinc concentrates, with water, are pumped out to a more or less level area, and stored in dams to dry by drainage and evaporation.In-the construction of these dams a clay bank is first thrown up around the proposed dam site. The concentrate and water mixture are then run in from the perimeter, the solids being continuously shovelled up to increase the bank height, while the clear water is drained off at the centre and returned to the treatment plant.These dams vary in size up to 57,000 sq. ft. in area; when completed the banks are about 12 it. high, and the capacity for the largest dams is about 350,000 cub. ft., say, 20,000 tons.The survey office is called upon for a monthly survey of these dams, generally three of which are in process of building or refilling. The puggy nature of the material prohibits walking beyond the bank of the dam, therefore the following method of estimating concentrates was evolved. No originality is claimed, but as the need is for a true survey, and the results have shown the accuracy of the method, a description is warranted. The dam site is first laid out into 10-ft. squares with a theodoliteand 150-ft. steel tape, the outside lines being placed about 15 ft. from the clay bank - 15 ft. is the maximum convenient distance from the bank for working with the levelling staff mentioned later.As the dam is rarely rectangular in plan, the outside points pegged out are not always the corner of a square, but are placed to give the greatest convenience in later work, that is to say, there may be triangles and irregular figures. The plan (Fig. 1) and photographs (Figs. 5 and 6) will give the general idea of the layout. At each point is driven a 3 ft. 6 in. round iron peg about 3 ft. into the ground. This peg is to permanently mark the point, and is not liable to be...

Jan 1, 1925

During the past Two years in reef gold mining, "indicators" have received great attention at the hands at the Victorian gold seekers. Many years ago, what was caned the" indicator lode," was struck in Ballarat East, on the course of which extremely rich deposits of gold were discovered but as to its being a .qeneral experience in reefs or leaders no one ever dreamed. Now, however, we find that these "indicators" are frequently to be met with, though they differ very much in different localities, making it, therefore, a difficult matter for other than a careful minel' to follow them. The necessity of following "indicators" for the purpose of developing gold is now recognized, and the policy of following them up has been attended with much success in this field. In the case of Messrs Shaw and Sons, at Wedderburn, those gentlemen began to work on an "indicator" here five years ago, and immediately thereafter more by accident than anything else they being at that time inexperienced as regards "indicators " came upon gold bearing quartz, which continued payable so long as the" indicator" aud the stone were in conjunction with each other, but as soon as they parted company the stone ceasedto be of any value then, by following the" indicator," as the latter intersected fresh bodies of stone they proved again more or less payable, until a fortnight or so ago the Messrs. Shaw turned out 4 tons of stone, which yielded £1,825, with also profitable workingup to the present moment. Where they are now working is a mile north of their original find thus proving that "indicators" travel considerable distances and have something to do with the gold deposits found in reefs. On the direct course of Shaw's "indicator," as high as hundreds of ozs to the ton was obtained from the stone but, just a few inches from either side in the same" leader," not a colour could be got. Whatever the cause-whether by electricity or some unknown force in nature-the gold is found on the course of these" indicators" and nowhere else, and-as each of the Victorian Government Geologists admit-their value to the gold-seeker as a means of leading to' gold cannot be over-estimated.

In, one stage of the purification sequence of the zinc sulphate electrolyte used at Risdon, cobalt is, precipitated as cobalt nitroso-,B-naphtholate, which is separated from the solution by filtration. Owing to the method of conducting the purification the filter cake contains much gypsum, unconsumed calcium hydroxide, basic zinc sulphate, and entrained zinc sulphate solution, Small amounts of iron and copper that have escaped previous purification steps are also precipitated with the cobalt as nitroso-,B-naphtholate. Thisprecipitate, normally carrying about 18% cobalt, is the raw material for the production of cobalt oxide, cobalt sulphate and cobalt metal.COBALT OXIDEThe main problem in the preparation of a reasonable grade of cobalt oxide from the filter cake is the economic separation ,of the cobalt nitroso-,B-naphtholate from the gypsum. This was solved by the application of flotation. It was discovered that the cobalt nitroso-,B-naphtholate, under correct conditions, would float without any addition agent, giving a relatively high grade concentrate. A plant, was built and has been in operation since 1936. The filter cake is pulped with water and pumped to one of two mechanically agitated tanks, eath capable of holding one day's output. Sulphuric acid is added until the free acid concentration reaches about 3 gm. per litre. Basic zinc sulphate is dissolved and calcium hydroxide converted to gypsum. The pulp, carrying about 2t lb. of solids per gallon, is pumped at a suitable rate to the first of a series of 10 flotation, boxes.. Each box is 3 ft. by 2 ft. 9 in. by 5 ft. deep, and, all have a common, pulp level, since the...

Jan 1, 1949

In undertaking to write a few notes on practical mining in Bendigo, the great quartz mining centre of Victoria, which just now is celebrating its fiftieth anniversary of gold mining, satisfaction must be expressed which is, no doubt, shared by all mining men and inyestors, that Bendigo has not lagged behind other Australian mining districts in the evolution of mining from its crude state, subsequent to the discovery of gold in 185 to its present more perfect state; and though it may be said that it has not yet reached the high pinnacle of perfection towards which advanced science and change of conditions may yet lead it in the course of future progress, yet, what has already been done in this respect, the adoption of the most approved methods appliances and modern machinery, tending towards greater and still greater efficiency, facility, and economy in our mining industry, must be accepted as a guarantee that in tne future as well as in the past, progress in our means of developing our mining resources will ever remain our watchword, by means of which future difficulties will be overcome as well as they have been removed in the past.The adoption of this principal, combined with a study of rigid economy, has raised gold mining here, as well as in other places, from a state of speculation, and sometimes wild speculation, to the status of a solid, stable industry, the strong supportand backbone of the country in which it flourishes. Two of the principal factors which have been to a great extent instrumental in bringing about this satisfactory state, must be specially mentioned.

Jan 1, 1902

By M Hourn, D Turner, P Voigt, D Mallah

The GPM Gold Project is located in Armenia, and consists of an open cut mine at Zod, near the Azerbaijan border, and a CIL processing plant at Ararat near the Turkish border. Mining at Zod commenced in 1976, and focused on near surface oxide ores, which overlay deeper refractory sulphides. Historical mining has now almost depleted the oxide ores, and the sulphide content of ore delivered to the processing plant at Ararat is increasing. Gold and silver recoveries through the Ararat plant were declining steadily.GeoProMining, the owners of the project, have expanded the Ararat facility to deal with the increasing sulphide content in the ore. In 2014, GeoProMining refurbished an existing concentrator on site to recover a sulphide concentrate from the ore, and have constructed an Albion ProcessTM plant to oxidize the refractory concentrate. Glencore Technology (GT) provided the Albion ProcessTM plant as a technology package.In July 2014, the progress of the GPM Gold Project Albion ProcessTM Plant was reported (Hourn, Voigt and Turner, 2014). At the time of writing, the construction of the plant was nearly complete. This paper presents an update of project progress, covering commissioning and ramp up of the GPM Gold Project.The commissioning phase occurred over June to August 2014, which included an M3,000 IsaMillTM fine grinding plant, a 6 tph limestone milling plant, a 60 tpd vacuum pressure swing adsorption oxygen plant, a 10 m residue thickener and a 12 tph Albion ProcessTM oxidative leach plant. Since commissioning was completed, ramp up occurred over the following three months with downstream gold recoveries from cyanide leaching reaching over 98%.CITATION:Voigt, P, Hourn, M, Mallah, D and Turner, D, 2015. Commissioning and ramp-up of the Albion Process at the GPM Gold Project, in Proceedings MetPlant 2015, pp 207–219 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

A variety of environmental financial assurance instruments are in use across the globe. This paper reviews some of the more common forms currently used in New Zealand, Canada, USA and Australia. In order to be effective, the form of assurance instrument selected needs to be aligned with a countryÆs specific environmental objectives, geography and political climates and also allow for a healthy investment climate. Industry and Government both have a strong interest in ensuring financial assurance criteria meet these objectives.   Recently Golder Associates have been involved in financial assurance assessments for various mining and quarrying companies across the South Island. Multiple stakeholders and regulatory agencies can make the setting of effective and fair financial assurance criteria a complex exercise for both regulatory agencies and industry.  The author relates experience gained in assessing financial assurance under current New Zealand legislation (RMA, 1991), effectively dealing with issues such as ôdouble bondingö and overviews potential approaches to dealing with transitional issues for historic and existing operating mine sites.

Jan 1, 2006

The recovery by flotation of some complex uranium minerals such as brannerite and davidite is described. Anionic reagents used for flotation of iron and titanium oxides' are suitable. If care is taken, to emulsify the reagents the slime fractions may be satisfactorilytreated.INTRODUCTIONUranium ores are usually treated by direct leaching with acid or alkali according to the nature of the gangue materials. Concentration of the uranium minerals prior to leaching is not commonly practised because of the earthy nature of most uranium minerals and the difficult mineral dressing problem they pose. Some of the harder complex oxides such as davidite and brannerite are amenable to flotation. This is fortunate since they usually require an expensive, strong acid treat~ent to dissolve the uranium. Flotation tests were commenced in 1949 by officers of the South Australian Department of Mines stationed at Adelaide, first in the School of Mines, then in the University of Adelaide and finally in Departmental mineral dressing laboratories at Thebarton. Separation of daviditefrom Radium Hill and Mount Victoria ores, brannerite from Crocker's Well ore, and secondary uranium minerals from Myponga ore was attempted.The development of the flotation reagents to separate the oxides from silica and the silicates is first described, then some of the results obtained are presented as tables.DEVELOPMENT OF FLOTATION REAGENTSThe davidite at Radium Hill is associated with iron and titanium oxides, qu;a,rtz and biotite as replacement deposits in shears. The davidite, rutile,' ilmenite and hematite usually occur in segregations from nut size to masses of several pounds. They are associated as a complexity of...

Jan 1, 1955

By A Batnasan, K Haga, A Shibayama, K Higuchi, H Takeuchi

High silica (SiO2), alumina (Al2O3), and phosphorus (P) contents in iron ore adversely affect the quality of iron products. The removal of those impurities from iron ore is an essential point in further iron ore processing. In this paper, the removal of P, SiO2 and Al2O3 impurities from iron ore by alkaline drying followed by reverse cationic flotation is discussed. The reverse cationic flotation experiments are performed using the iron ore samples without and with alkaline drying pretreatment. All other flotation conditions except pulp pH (4–12) and particle size distributions (-45 to -250 μm) are held constant. A typical collector and frother, such as dodecylamine acetate (DAA) and methylisobutylcarbinol (MIBC), are used in the flotation experiments. Alkaline treatment is conducted before flotation using sodium hydroxide at fixed conditions. The impact of alkaline drying on the performance of iron ore flotation is evaluated based on the removal rates of P and SiO2 + Al2O3, iron grade, and iron recovery compared with the iron ore flotation without alkaline drying (direct flotation). X-ray diffraction (XRD) analysis indicates hematite and goethite are the main minerals in the iron ore, which assays 62.8 mass per cent Fe, 0.232 mass per cent P, 7.1 mass per cent SiO2 + Al2O3 (total) determined by X-ray fluorescence analysis (XRF). Results indicate that a combined approach is more effective for removing P and SiO2 + Al2O3 impurities from iron ore than the direct processing technique because the maximum removal rates of P and SiO2 + Al2O3 are 48.2 per cent and 66.5 per cent from the alkaline dried iron ore when 8.4 per cent and 13.1 per cent from the non-alkaline dried iron ore.

Sep 18, 2023

COMPRESSED air is held in high esteem by the mining engineer as a medium for the transmission of power. The transmission, however, is accompanied by a high percentage of loss. Of the total work done by the steam cylinder'in compressing the air inthe air cylinder, less than 50% is ultimately utilized by the machines underground. These losses are due to its essential and inherent properties as a gas. One of the sources of loss is that due to transmission through the pipes which distribute the air from the receiver to the various places where it is used. As the capacity and economic design of air-compressing plant are influenced by this source of loss, it may be of interest to give an outline of how estimates may readily be made'in practice of thediameter of pipes, quantity of air discharged, and the drop in pressure occasioned.In hydraulics we have a general formula given M Rankine's "Civil Engineering" :It was suggested, the writer believes, in the first instance by D'Arcy, that this formula could be made to apply to an elastic...

Jan 1, 1918

DESCRIPTION OF OREThe ore consists, in general, of a very finely grained mixture of sphalerite, galena, and pyrite, with a gangue of quartz and schistose material, and contains about one ounce of silver to the unit of lead.Minor minerals are chalcopyrite, tetrahedrite, and ruby silver. The amount of gangue within the ore-bodies themselves is usually less than 20% of the weight of the whole. The ore is banded in a way that corresponds to the structure of the original schists, and is by no means uniform in composition-at one point, for example, blende may predominate, and a few feet farther on the body may become highly pyritic.Owing to the intimate association of the mineral constituents of the ore, it is very difficult to separate them from one another.Although this remark applies to ore from all parts of the field, the difficulty is particularly noticeable with Rosebery ore, the minerals of which are more intimately mixed, and are of smaller grain size than are the minerals of the Hercules ore.To effect a reasonably clean separation, it is necessary to grind the ore so that 90% passes a 200-mesh I.M.M. screen. Microscopic examination of the crushed product shows that 85% of the minus 200-mesh material is less than 30 microns in diameter, or, in terms of screen sizing, is minus 400 mesh. Particles under 30 microns are found to consist, of one mineral only, but in particles over this size separation has not always been effected. For instance, it is known that part of the galena and of the pyrite in the zinc concentrate is associated with sphalerite, and that part of the galena in the mill residue is associated with pyrite. There is only slight association between the minerals in the lead concentrate.

Jan 1, 1927

The oxidation of ferrous sulphate to ferric sulphate with air and oxygen in a gas lift percolator was investigated with initial Fe2+ concentrations in the range 0·01 M to 1·0 M,temperatures in the range 20-80°C, and pH in the range oto 2.The rate of formation of Fe3+ was found to be well described by the rate expressionEquation 1and a consistent mechanism is proposed.The presence of Cu2+ was found to cause an increased rate of oxidation, the effect being greater with Cu2+ concentrations increasing in the range 0·001 M - 0·01 M in 0·2 M Fe2+. The effect of other solutes containing Ni, Zn, Mn, Co, Hg, Cl, Mo, NH4, As, Cr, or Na at a concentration of 0·001 M in 0·2 M Fe2+ was negligible.

Jan 1, 1972

By Hindmarsh J. W, McCoy A. E R

Instantaneous outbursts of coal and gas have occurred at various times in several working districts of Metropolitan Colliery, N.S.W.They have occurred in headings only, under both hand and mechanised conditions, and with seam gas ranging from mainly methane to nearly pure carbon dioxide. A modification of inducer shotfiring using a shear cut was introduced in 1955, and in 1961 full face firing both to a machine cut shear and off the solid was introduced. The current series of outbursts -1961 to 1963 - has been induced under these systems with full control of the time of outburst, but without prediction, and with some disappointing production features.Various aspects of current conditions and practices at Metropolitan are considered singular, such as the coarse granulometry of outburst coal, the prevalence of floor heave, the absence of strong structures at outburst sites, the possibility of outburst at any stage in pillar formation up to the last few yards, the effect of rate of advance on outburst occurrence, and the mildness of many outbursts experienced.It is concluded that inducer shotfiring is a reliable control but it suffers by comparison with outburst-free conditions, and that control by preyention would be preferable.INTRODUCTIONThe phenomenon of instantaneous outbursts of coal and gas has been described in detail previously (Hargraves, 1958). Briefly, it is a combined gas and stress hazard of deep coal mining, usually occurring in virgin work and during active face advance, when coal and seam gas burst from the face into the workings.Instantaneous outbursts have occurred sporadically at Metropolitan Colliery, N.S.W., since 1895. Early outbursts were recorded as firedamp and recent outbursts are of blackdamp.Mining methods used have been conventional hand work, with progressive and relatively complete mechanisation over the past 25 years to substantially conventional...

Jan 1, 1964