TACLOBAN CITY -- The Mines and Geosciences Bureau (MGB) said the landslides in Biliran province last month was caused by heavy downpour and unstable soil and not by mining activities.

MGB Eastern Visayas regional information officer Celeste Faith De la Cruz refuted claims that mining was the cause of massive landslides that buried several people alive when Tropical Storm “Urduja” dumped heavy rains in the province mid-December.

“Geologists have not come across any ongoing or remnants of previous open pit mining or quarrying activity within the vicinities of the landslide areas that may have contributed to such occurrence of landslides,” De la Cruz said Monday.

The MGB official tagged some factors that contributed to soil erosion based on their assessment conducted on Dec. 28, 2017.

The mudslide was largely attributed to the intensely weathered, fractured, and altered volcanic with clay-like materials underlying the areas, according to MGB.

“Continuous heavy rainfall brought about by storm Urduja, which loosened the topsoil with boulders and uprooted the trees,” she said in a mobile phone interview on Monday.

The landslide-hit areas, according to MGB, had a slope gradients of 45 percent (very steep), making the areas highly susceptible to erosions.

The presence of "points of weaknesses" along road cuts and riverbank portions also contributed to the landslide.

These "points" include fractures and deteriorated rocks.

“Another factor is the unstable grounds due to road development, farming, and poor drainage system,”

The Biliran provincial disaster risk reduction and management council reported that landslides and flooding brought by the tropical storm had killed 42 people and 14 others missing.

The weather disturbance had displaced 22,535 families or 90,000 persons in Biliran province alone.

Biliran is one of the country's smallest provinces with a land area of 536 square kilometers and a population of 171,612 as of 2015. (PNA)