A quarry is a large deposit of rock such as granite which is mined for use in construction projects. Quarries can be found all over the world, and most contain a heavy concentration of a particular type of rock such as Marble, Limestone, slate, Chalk, China clay, Cinder, Clay, Coal, Construction aggregate (sand and gravel), Coquina, Granite, Gritstone, Gypsum, Ores, Phosphate rock, Sandstone, gypsum. In many nations, the word quarry is used interchangeably for two types of quarry: gravel pits, from which gravel and particulate matter are extracted, and dimension stone quarries, from which large chunks of sheets of rock are extracted for use in building. Dimension stone is used to make tiles, flagstones, counters, roofs, and other projects which require large slabs of uniform stone.
Unlike other types of mines, a quarry is usually not dug out underground, and rarely reaches a depth greater than 60 feet (18 meters). A shallow pit is excavated into a deposit of rock which runs close to the surface, and the pit is slowly expanded to remove valuable rock material. If the quarry is being used to extract gravel or fill, explosives may be used to break it up before it is removed and loaded into trucks. If dimension stone is required, the excavation process is more painstaking to ensure that the stone is not damaged.
Quarrying by blasting is prevalent throughout history and began with the first use of gunpowder around 1627. A hole about 2 inches in diameter and 12 to 20 inches deep drilled into the rock is the "point" of a triangle carved into the rock to direct the blast. The "plug-and-feather" method improved on blasting. Small holes were drilled with shims (thin wedge-shaped objects) and wedges inserted. Force was then applied to split the stone so that it broke with a flat face. Another technique used -- the flat wedge method -- is not in use today. A chisel chipped out a line of holes into which wedges were inserted and then tapped in sequence to let the stone split on its own.
Today's methods of quarrying are technologically advanced and customized for the location. At some marble quarries in Europe, diamond chainsaws cut the stone, and then the entire rock face is pulled off with construction equipment or broken into blocks and further trimmed with chainsaws. In a Brazilian quarry, oxygen burners create large vertical cuts and diamond chainsaws create smaller ones; then blocks are cut out. In a Vermont slate quarry, blasting is used along with a "softer hit" of black powder to loosen the stone.
While a quarry is in active operation, it must be protected from groundwater seepage and rain, or it will turn into a small pond or lake. Many quarries are surrounded with moats of impermeable material to prevent seepage, and are also covered to prevent rain from accumulating in the open pit. In some cases, pumps may be installed to assist with removing water from the quarry. The company which built the quarry also maintains roads to and from the site, and sometimes builds a temporary processing center for the rock so that it can be removed, graded, and processed on site, with excess being disposed at the site rather than miles away.
After a quarry is abandoned, it is usually fenced off or otherwise secured to prevent people from injuring themselves there. In some cases there may be toxins present at the site, due to the way in which the rock was extracted. In others, as the quarry slowly fills with water, it may be a tempting place to swim. However, the quarry may pose hazards to swimming through objects in the water, depth, coldness, or toxins which may have leached into the water. In some cases, an inactive quarry may be converted into a swimming area, with modifications made to create a safe swimming and recreation area. When selecting a technique for quarrying, the environmental impact is a consideration. Quarrying can ruin the beauty of an area and affect local wildlife; the machinery and trucks can cause pollution and noise. The land will never return to the way it was after quarrying, but with planning, a gravel and sand pit can become a leisure facility like a lake or a home for local wildlife.
This Earth Cache will take you to a beautiful abandoned quarry which with the passing of the years had become an amazing place for our local wild fauna and flora, breath taking landscapes within the middle of this concrete jungle called the city of Doral. This particular quarry was mainly used to extract tons and tons of Limestone and construction aggregate (sand and gravel).
You will enjoy a relaxing 1+ mile hike to the cache’s coordinates, but I do advise you to enjoy and learn as you hike to GZ because this area is full of interesting clues to what a quarry used to be as well amazing rock formations left by the years in which it was active. Not counting the many more caches you can find along the way.
Now that we had learned a bit of what a quarry is, it is time to test your knowleged about it. Please answer the fallowing questions correctly in order to be able to claim the smiley for this cache.
- What is a quarry?
- Name four of the most commonly mined types of rock in a quarry.
- What is the difference between a mine and a quarry?
- What is the most commonly used method of quarrying throughout history?
- What usually becomes of a quarry once is abandoned?
- To prove you were here tell me what kind of stones do you see at way point "A1 & A2" Which one is Limestone and which one is Gravel.
