Slate formation is estimated to have occurred up to 500 million years ago and is a metamorphic rock; that is to say it has transformed from one type of rock into another. In the case of slate, it was formed from shale.

Generally slate is found in mountainous regions as these are the areas where most rock movement has taken place. The tremendous pressure bearing down on the shale, together with intense heat causes the shale to transform. The shale gets compressed and forms layers which can easily be separated. This is why slate is ideal for roofing and flooring because to some extent it is already the correct thickness for tiling when it’s mined.

Over time, if slate isn’t mined it metamorphosis occurs again and it can transform into rocks known as phyllite, schist and then gneiss. Some slate is found near the earth surface and is often worn away due to erosion from wind and rain and collects in low lying areas. The slate particles and other rock particles gradually get forced or cemented together and form sandstone.

The color of slate varies significantly although it’s generally considered to be gray in color. It can be many shades of blue, yellow green brown and red, depending on where it was formed.

Slate can be extracted in three ways; open quarries, underground mining and pit mining. Slates forms into vein-like strips and the angle that the vein runs determines the type of mining required to extract it. Open quarries are the easiest method of extraction as the slate is near the surface and follows the line of the mountain. Underground mining is used to dig tunnels into the side of a mountain until the tunnel meets the vein of slate. The tunnel then follows the angle of the vein so it can be extracted. Pit mining occurs when the angle of the slate vein is practically vertical. A pit is drilled downwards until it meets the vein of slate then extraction begins.

Once the slate is mined it is processed to form the slate tiles you are familiar with. The machinery removes the rough edges and cuts the slate into fairly regular shapes ready for transportation. Further processing takes place, depending on what the slate tiles are going to be used for. For example roofing tiles are shaved and smoothed to form identical shapes as are slate tiles used for internal flooring. Slating used for patio areas in often less processed giving the tile a more natural look.

Despite many manmade materials having been developed to use for roofing and flooring, slate remains extremely popular. It is very durable and strong; slate roofing can last well in excess of 50 years and even then only a few tiles may need replacing. If you use slate for external flooring and it is professionally laid, it will last a lifetime and just gets better and more natural looking as it ages.

Virginia Slate maintains a large inventory of all forms of slate for contractors and builders, including structural slate.

http://www.virginiaslate.com maintains a large inventory of all forms of slate for contractors and builders, including structural slate http://www.virginiaslate.com/inventory/structural.html.

Author Bio: Virginia Slate maintains a large inventory of all forms of slate for contractors and builders, including structural slate.

Category: Advice
Keywords: Home, Repair, Environment, Construction, Advise, Tips