|
AUTOMATIC HOIST |
|
The first automatic hoist was built by Eric Cattrell at
Lightning Ridge in about 1961. Hoists have a winch (differential or slip type
drum) which is located on the surface of a mine and is used to lift a
bucket of opal bearing claystone to the surface. The system is
activated from underground and is completely automated.
Each time the hoist is activated, the bucket travels vertically up the
mine shaft using the steel access ladders as guide rails. Once at
the surface the bucket then travels along a curved frame which inverts the
bucket and empties the dirt on to a waiting truck or stockpile.
After inversion the bucket automatically returns down the shaft to its starting position ready for an other load .
The early hoist used a bucket witch was usually an old 13 gallon oil
drum. In later years the same principal was used for the "super hoist"
which has a hoisting bucket that can carry about 200 litres (44 gallons)
of opal bearing claystone each time it is operated.
Hoist bucket loaded with opal bearing claystone, Coocoran opal fields,
Lightning Ridge. |
|
Hoist tipping opal bearing claystone into the back of a truck, Coocoran
opal fields, Lightning Ridge. |
|
Hoist that has been used to tip opal bearing claystone directly onto the
ground, Shallow 4 Mile opal field, Lightning Ridge. |
|
|