The Highways Department insists its underground blasting, scheduled next week, to expand a road that cuts through Dong Phayayen-Khao Yai Forest Complex will not negatively affect the environment.
The blasting, set to be carried out between Monday and Dec 31 this year, is needed because part of the extended road will be turned into an underpass. This requires workers to dig a tunnel, department expert Phonchai Sirarom said on Friday.
The digging will be done deep. Rubber sheets and car tyres will be used to cover openings. As a result, he said, "only small amounts of soil will be dispersed and noises and vibration will be small".
The department plans to change areas above the underpass back into part of a forest so that wild animals, which have to cross over the roads, can walk more safely.
Officials need to close traffic on the road on certain days to carry out the blasts between 2pm and 2.30pm, Mr Phonchai said. However, construction will be halted during long holidays in December to avoid inconveniencing tourists.
The expansion of the road, which links the Khao Yai and Thap Lan national parks, is needed as the two lanes cannot serve the increasing traffic, according to the department.
Once the road is extended to four lanes, travel between Prachin Buri's Kabin Buri district and Nakhon Ratchasima's Wang Nam Khieo will be faster.
The road is part of Highway 304, which is under construction to extend its traffic lanes. The project aims to help facilitate goods transport between the Northeast and eastern coast, home to the Laem Chabang Sea Port and Eastern Seaboard Industrial Estate.
The department is aware the construction must be done with great care as it is in the forest area, Mr Phonchai said.