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Opal and Mining

Index

 

Industry & Investment NSW    Lot 60 Morilla Street(PO Box 314)Lightning Ridge 2834 Telephone: (02) 68 299 200 Fax: (02) 6829 0825

 

Geology     Opal is currently being mined from depths between 1 metre (3 feet) and 30 metres (90 feet) below the surface. The opal is found in sedimentary rocks that were deposited in a freshwater environment during the Cretaceous period, about 110 million years ago...................

 

Survey    The object of surveying a claim is to provide the Mining Registrar's office with a diagram which shows where you which to register a claim in relation to a fixed point or survey mark....................

 

Mark out of a Claim    A steel picket or wooden post(at least 75mm thick)must be placed and protrude at least one metre out of the ground. Trenches(1metre long and 150mm deep)must be dug from each corner post along the direction of the claim boundaries...................

 

Propping    Propping is a process whereby timber is used to stabilise underground mine workings. By reducing the risk of cave ins, propping improves safety for opal miners while also maximising the amount of opal bearing claystone that can be excavated....................

 

Drilling Rigs   Prior to the introduction of drilling rigs to the Lightning Ridge region, nearly all mine shaft excavation and prospecting was undertaken by manual methods...................

 

Automatic Hoist    The principal of operation is a winch (differential or slip type drum)which when activate from down in the mine would pull a bucket up using the ladders as a guide going up and around a curved frame which invert the bucket and empties the dirt on to a waiting truck ...................

 

Blowers    There are in excess of 200 blowers in Lightning Ridge.Althrough there may have been some blowers prior to the first commercially built in Lightning Ridge which was built by Knud Nexo in December 1973...................

 

Wet Puddlers and Agitators     The wet puddler is used to separate the Opal clay from the actual Opal and harder particles.The Puddler is basically a basket made out of 1/4 inch mesh with a rotating plate at the bottom of the basket driven by an external power source through a modified diff from a truck....................

 

Underground Digging Machines    Under ground Diggers came to LIGHTNING RIDGE in the late 1970's and were mainly self driven bobcat type but in 1980 the first purpose built digger was made by Knud Nexo as an add on to the blowers.

 

Opal Glossary   Opal Mining Glossary , The information is extracts from Len Cram's book" A Journey with Colour"...................

 

Buying Opal ?    So, are you going to purchase an opal while you are in Lightning ridge? Well,there is probably no better place in the world for doing so. At Lightning Ridge sellers display both local stones and opal from other Australian fields. Let us first look at the types of opal available....................


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Last Update Pre 2006