Owela Feldspar Open Pit Mine and Mineral Processing Plant

Owela Feldspar

Location

Situated in Central Province of Sri Lanka at Owala –Kaikawala area.

History

Feldspar deposit was located at the boundary of Wanni and Highland complexes Due to that it has igneous origin. It is an activated boundary. Mineral conversion is still happening in that. Hot springs are more common feature in that area. It is the 2nd biggest mine of feldspar in Sri Lanka. The mine was started in 1973. Open cast mining of the deposit carried out by the Ceylon Ceramics Corporation

Geology and mineralogy

Feldspars are the most abundant minerals in the Earth’s crust. They are silicate minerals and are referred to as framework silicates because the tetrahedral (of Si and Al four coordinated by oxygen) are linked together in three dimensions to make a framework. Note the tetrahedral are connected through sharing of all oxygen atoms in the coordination polyhedral. Two types of feldspar.

Alkali Feldspar - Potassium(K) Sodium(Na) aluminosilicate
Plagioclase Feldspar - Sodium(Na) Calcium(Ca) aluminosilicate

The feldspar occurs in a large mass of pegmatite discovered by the Geological survey in the sixties. The deposit contain mainly K feldspar. Other than that it contains quartz, mica, clay minerals, fluorspar (CaF2) etc. Has two direction perfect cleavage. There were some cavities on the feldspar deposit which have filled with Quartz crystals, feldspar crystals, and Clay minerals.

About deposit

Using spiral way mining method to mine the deposit to gain the maximum yield. The overburden of several meters should be removed before mining. But the due to the unsymmetrical mining there can see some isolated bodies. Up to now 1 ¾ from the deposit has mined. The major problem of that deposit is unwanted fluorspar. It has secondary formation and 2 direction cleavage. Because of this fluorspar the tiles which made using feldspar get crack under sunlight. Near the deposit there can see dolomite band and other side of that paddy cultivation. When the mine reach to that paddy cultivation level water is flowing on to the surface. It also a big problem to extract feldspar.

Processing

Using caterpillars overburden is removing. Then deposit can be visualized. Then bore halls are drilled to the depth of 1m manually or using drilling machines. Then several drill halls are filled with explosives they are blasted one by one by set the timing. Then blasted material (feldspar) is loaded to the trucks with using caterpillars and transported to store before sending to the plant.

After that crush the feldspar using primary jaw crusher. Overflow (above 5mm particles) feldspar of jaw crusher send to the corn crusher (secondary crusher) along conveyors. The output particles diameter of jaw crusher is 1-1 ½ inches. Using vibrating plate particles are further separate into different particle sizes (13mm, 10mm, and 5mm)

Uses of Feldspar