|
The slate industry is the industry related to the extraction and processing of slate. Slate is either quarried from a ''slate quarry'' or reached by tunneling in a ''slate mine''. Common uses for slate include as a roofing material, a flooring material, gravestones and memorial tablets, and for electrical insulation. Slate mines are found around the world and the major slate mining region in the United Kingdom is Wales: in Cornwall there are a number of slate quarries (famously the village of Delabole) and in the Lake District there are numerous slate mines and quarries. 90% of Europe's natural slate used for roofing originates from the Slate Industry in Spain.〔(European Association of Mining Industries website ) retrieved on 26/01/2010〕 In the remainder of Continental Europe and the Americas Portugal, Italy, Germany, Brazil, the east coast of Newfoundland, the Slate Valley of Vermont and New York, and Virginia are important producing regions. The Slate Valley area, centering on a town called Granville in the state of New York is one of the places in the world where colored slate (i.e. slate which is not grey or blue) is obtained. (A fuller account is given in the article Slate: section Slate extraction.) == Slate Industry in Spain == (詳細はGalicia being the primary source of production. In Galicia, the larger slate production companies are concentrated in Valdeorras in Ourense, with other important sites being situated in Quiroga, Ortigueira and Mondoñedo. The slate deposits in this region of northern Spain are over 500 million years old, having formed during the Palaeozoic period. The colour and texture of the slate produced is largely dependent upon the tectonic environment, the source of the sedimentary material from which the slate is comprised, and the chemical and physical conditions prevalent during the sedimentation process. The region has been subjected to periods of volcanism and magmatic activity, leading to a unique geological development in the region. An important use of Spanish slate is as a roofing material. It is particularly suitable for this purpose as it has a low water absorption index of less than 0.4%, making it very resistant to frost damage and breakage due to freezing. Tiles produced from Spanish slate are usually hung using a unique hook fixing method, which reduces the appearance of weak points on the tile since no holes are drilled, and allows narrower tiles to be used to create roofing features such as valleys and domes. Hook fixing is especially prevalent in areas subject to severe climatic conditions, since there is a greater resistance to wind uplift as the lower edge of the slate is secured.〔Galician and Spanish Slate website (“Hook Fixing” ). Retrieved on 26/01/2010〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Slate industry」の詳細全文を読む スポンサード リンク
|