New study sheds light on Karst bauxite deposit in Samar

Karst bauxite deposit is primarily formed by the prolonged exposure of silicate rocks to intense tropical weathering. Over the years, due to weather conditions, the less stable materials got stripped, thus allowing aluminum-rich minerals to concentrate within the rock mass.

The team carried out sampling from test pits reaching depths of up to four metres. Additional samples were taken from an existing drill core extending more than 11 metres below ground. Leveraging modern X-ray techniques,  lab analysis was conducted to evaluate both mineral composition and chemical content.

According to the study, gibbsite and boehmite are the dominant aluminum minerals in this area. Other associated minerals include goethite, hematite, anatase and kaolinite. According to the researchers, this combination reflects long periods of dehydration and compaction under warm, humid conditions.

Chemical testing revealed high levels of aluminum oxide, together with measurable amounts of silica, calcium oxide, phosphorus pentoxide and titanium dioxide. The study has also observed that the concentration of titanium in this area is increased with depth, while silica and calcium showed a declining trend.

The Paranas deposit is under the management of Alumina Mining Philippines Inc., with exploration activities reported to be in an advanced phase. Previous geological work in the area was conducted between 2003 and 2017.

The researchers said the findings could support more informed and responsible mineral development in Samar. The study offers a broader understanding of bauite formation in the Philippines, where complex geology continues to attract scientific and commercial interest.