Slate Mining Research Articles

Comparison of Kriging and Neural Networks With Application to the Exploitation of a Slate Mine

To carry out an efficient and effective exploitation of a slate mine, it is necessary to have detailed information about the production potential of the site. To assist us in estimating the quality of slate from a small set of drilling data within an unexploited portion of the mine, the following estimation techniques were applied: kriging, regularization networks (RN), multilayer perceptron (MLP) networks, and radial basis function (RBF) networks. Our numerical results for the test holes show that the best results were obtained using an RN (kriging) which takes into account the known anisotropy. Differing deposit configurations were obtained, depending on the method applied. Variations in the form of pockets were obtained when using a radial pattern with RBF, RN, and kriging models while a stratified pattern was obtained with the MLP model. Pockets are more suitable for a slate mine, which indicates that the selection of a technique should take account of the specific configuration of the deposit according to mineral type.

Design and planning for slate mining using optimisation algorithms

This paper describes the application, for the first time, of design, planning and scheduling algorithms to the mining of ornamental rock. For the application, a model of an ornamental slate deposit was created that included a block model and a financial model of the deposit. The block model contains information on useful or exploitable slate content, which is equivalent to metal content for the traditional mining sectors. The financial model introduces the concept of cutoff grades to slate. Cutoff grades are a logical consequence of the mine planner having a choice as to whether or not to use diamond wire to cut the blocks. The techniques applied in this sector of crucial importance to the Spanish mining industry were the Lerchs and Grossmann algorithm, parametric analysis and the Milawa algorithm.

Lymphopenia in occupational pulmonary silicosis with or without autoimmune disease.

An increased prevalence of autoimmune diseases such as rheumatoid arthritis has been demonstrated in silica-exposed patients. The aim of this study was to determine the peripheral blood lymphocyte phenotype in a population of silicotic workers employed in the slate mines of the district. Silicosis was assessed in 58 patients according to the International Labor Office's criteria. Clinical and biological data including flow cytometric evaluation of the lymphocyte subsets were compared with those from 41 healthy volunteers. The silicotic patients had a higher prevalence of autoimmune diseases (6/58 versus 0/41: P < 0.05) and of elevated antinuclear antibody titres compared to the control group. A very significant decrease of total lymphocyte count (P < 0.001) involving B, T and Natural Killer cells was found in silicotic patients as compared with matched healthy volunteers. A significant increase in the percentage of activated T cells (12.3%) was observed in the silicotic group as compared to 6.5% in the control group (P = 5 x 10(-5)). Our results show that in silicotic patients, the absolute number of circulating lymphocytes is diminished with an increased proportion of activated T cells. Whether these findings could predispose to the development of autoimmune disorders is discussed.

Impact of high aluminium loading on a small catchment area (thuringia slate mining area) —geochemical transformations and hydrological transport

A field study was performed on the effects of acid mine leachate from slate mine tailings seeping into a small river passing through the tailings. Before entering the tailings the river water has high alkalinity which neutralizes acidity upon mixing with leachate within the tailings. Downstreams of the tailings the pH of the river water ranges about pH = 8, the water contains high concentrations of sulfate (≈1500 μmol/l) and particulate bound aluminium (≈80 μmol/l), but low concentrations of dissolved aluminium (≈3 μmol/l). It is therefore assumed that Al(OH)3 colloids are precipitated during the neutralisation process and transported out of the tailings. The concentration of particulate bound aluminium along the river shows a strong correlation with the concentration of sulfate, which indicates that particulate bound aluminium is conservative. It therefore seems that under dry weather conditions (under most of the sampling was performed) no chemical retention mechanism exists which confines the distribution of aluminium to a restricted part of the catchment area. In contrast, the white river sediment is rich in both aluminium and sulfate, which suggests the temporary formation of aluminium hydroxosulfate minerals. Favorable (i.e. acidic) conditions may prevail at high discharges where the acidity accumulated in the tailings is flushed into the river with its subsequent acidification.

Geological problems in the exploitation and optimization of rock excavation in roofing slate mining

Geological problems in the exploitation and optimization of rock excavation in roofing slate mining

Dimension and support of underground slate mines

Dimension and support of underground slate mines

Aluminium species distribution during mixing of acid coal and slate mine drainage with neutral stream waters

We measured the spatial variation of aluminium concentrations and computed its species distribution before and during mixing of acid mine drainage containing waters with near neutral receiving waters. Acid mine drainage was collected from the Loquitz Creek, Thuringia, Germany, and Garvey Creek, Westland, New Zealand, which drain slate mine workings and coal mine workings, resp. The acidneutralizing capacity (ANC) of the receiving streams and the mixing with waters having low Al-concentrations cause a decrease of aluminium concentrations below the confluence. Depending on volumes and ANCs involved, the content of free Al and sulphate bound Al decreases after mixing in favour of organic and hydroxide bound Al. In addition, below the junction of the Loquitz Creek and the Aue Creek with its high ANC, we observe the precipitation of aluminium hydroxides and Al hydroxysulphates.

Blue Slate Quarrying in South Devon: An Ancient Industry

This article traces the history of a little-known area of slate quarrying which was of importance in the medieval period and again active in the eighteenth and nineteenth centuries. In the Meadfoot Beds and Dartmouth Slates of the Devonian period in Devon blue slate was quarried extensively, chiefly for roofing tiles but for a variety of other uses as well. The fissile slate served as building and walling stone, paving, coping, steps, slabs, window-sills, lintels and hearthstones; it was used for billiard-tables, cisterns and fencing, and incised by mason-craftsmen for tombstones, sundials and wall plaques. The medium-sized or small South Devon quarries, now all disused except one, are sited on hillsides or sea cliffs, most of them close to means of water transport — rivers or the sea. There was one slate mine in the area.

Blue Slate Quarrying in South Devon: An Ancient Industry

Abstract This article traces the history of a little-known area of slate quarrying which was of importance in the medieval period and again active in the eighteenth and nineteenth centuries. In the Meadfoot Beds and Dartmouth Slates of the Devonian period in Devon blue slate was quarried extensively, chiefly for roofing tiles but for a variety of other uses as well. The fissile slate served as building and walling stone, paving, coping, steps, slabs, window-sills, lintels and hearthstones; it was used for billiard-tables, cisterns and fencing, and incised by mason-craftsmen for tombstones, sundials and wall plaques. The medium-sized or small South Devon quarries, now all disused except one, are sited on hillsides or sea cliffs, most of them close to means of water transport — rivers or the sea. There was one slate mine in the area.

The Geographical Distribution of Mortality Ascribed to Certain Pneumoconioses During 1968–78 and Related Industries in England and Wales

Abstract Maps of mortality rates from certain pneumoconioses for men and women in England and Wales during 1968–1978 are presented and demonstrate striking geographical patterns. The map for silicosis is mainly related to the distribution of slate and tin mining, that for coalworkers' pneumoconiosis to coal mining, and that for asbestosis to the areas of past high usage of asbestos.

Interaction between erythrocyte plasma membrane and silicate dusts.

Lysis of erythrocytes in vitro leading to release of hemoglobin has often been used as a convenient test system for predictive toxicological evaluation of noxious particulates encountered as pollutants in occupational and environmental atmospheres. However, in spite of several studies with silica and silicate dusts, the exact biochemical mechanism for membrane damage is not clear. Therefore, detailed biochemical studies were conducted. Screening of a large number of fugitive dust samples indicated that the dissolution of silica under assay conditions has a qualitative relation to hemolytic potency. The strong capacity of slate mine dust to cause hemolysis was studied in detail. The kinetics of lysis indicated that on prolonged contact the adsorption of hemoglobin altered the lytic index. Coating of dust with serum, albumin or polyvinylpyrrolidone (PVP) and some lipids reduced lytic potency markedly, while EDTA was ineffective. Altering the surface chemistry of dust by heating, alkali treatment, washing with water, and acid washing reduced hemolysis in increasing order. Thus, chemical interactions between dusts and membranes are involved in hemolysis, and it may be concluded that the interaction of dust constituents with biomembranes is one of the likely mechanisms involved in the toxicity of particulate air pollutants.

Biochemical studies on the toxicity of slate mine dust.

As part of a detailed experimental study of the pathogenicity of disease of slate dust workers, the early biochemical changes in rat lung from 1 to 90 days after intratracheal inoculation of slate dust of particle size below 5 micron were investigated. A severalfold increase in free cell population (initially macrophages) was elicited by the dust. The free activity of acid phosphatase tended to increase along with a break of lysosomal latency with increasing exposure period. However, actual release of enzyme activity into the acellular fraction was low. The phospholipid content varied both in cellular and acellular fractions, indicating altered turnover of membrane lipids and surfactants. At advanced periods of the study, sialic was found to be released into the acellular fraction, indicating membrane damage. Considerable decrease in glucose-6-phosphate dehydrogenase activity and free sulfhydryl content and enhanced osmotic fragility of erythrocytes were also recorded. These results indicate the potential toxicity of slate mine dust.

Biochemical Studies on the Toxicity of Slate Mine Dust

As part of a detailed experimental study of the pathogenicity of disease of slate dust workers, the early biochemical changes in rat lung from 1 to 90 days after intratracheal inoculation of slate dust of particle size below 5 micron were investigated. A severalfold increase in free cell population (initially macrophages) was elicited by the dust. The free activity of acid phosphatase tended to increase along with a break of lysosomal latency with increasing exposure period. However, actual release of enzyme activity into the acellular fraction was low. The phospholipid content varied both in cellular and acellular fractions, indicating altered turnover of membrane lipids and surfactants. At advanced periods of the study, sialic was found to be released into the acellular fraction, indicating membrane damage. Considerable decrease in glucose-6-phosphate dehydrogenase activity and free sulfhydryl content and enhanced osmotic fragility of erythrocytes were also recorded. These results indicate the potential toxicity of slate mine dust.

Ergebnisse einer kleintektonischen Untersuchung in der Dachschiefergrube "Wilhelm Erbstollen", Kaub a. Rhein

Ergebnisse einer kleintektonischen Untersuchung in der Dachschiefergrube "Wilhelm Erbstollen", Kaub a. Rhein

Industrial pulmonary fibrosis with special reference to silicosis in Wales

Summary o 1. The industries included in the Silicosis and Asbestosis Medical Arrangements Scheme are reviewed. 2. The incidence of silicosis continues to be serious, and in Wales occurs chiefly in the coalfields of South Wales and in the Slate Mines of Merionethshire. 3. Ninety per cent. of the total certificates of disablement awarded by the Silicosis Medical Board in Great Britain in the coal mining industry are granted to workers in the South Wales Coalfield. 4. The results of a survey of a group of Welsh slate quarry miners is given, showing the high incidence of silicosis in that industry. 5. Silico-tuberculosis is much higher in the slate quarry miners than in coal miners, but it is suggested that infective silicosis is more prevalent in coal miners than hitherto suspected. 6. The radiological appearances of silicosis is described. 7. The complications and sequelae are discussed. 8. The prevention of the disease is both an engineering and a medical problem. 9. Tuberculous workers should be kept out of the industry, and to this end all new entrants into the industry should be X-rayed. 10. Institutional treatment should be given to all silicotics on full compensation and they should be included in a care scheme on the same lines as such a scheme for the tuberculous. 11. The rehabilitation of those workers on partial compensation should be undertaken.

Recent progress in slate technology

Roofing slate has its own regulations and standards, as with other natural stones. The two main markets for roofing slate are USA/Canada and Europe. Given the very long tradition of slate mining in these two areas, it is no surprise that the first regulations for roofing slate were developed there. In the USA and Canada, the technical requirements are compiled in the standard ASTM C406, while in Europe test methods and requirements are defined in EN 12326. There are also standards from China (GB/T 18600) and India (IS 6250), the emerging production countries in the slate market. This review article analyses and compares the current test methods for roofing slate. Also, new test methods are proposed in order to complement the information of the official standards.