The construction phase of the CLSG interconnection project is showing strong progress in Liberia and Sierra Leone as key activities are already underway.
In Liberia, an Aircraft has been hired and brought in by two EPC Contractors, Saudi Arabia based NATIONAL CONTRACTING COMPANY LTD and JV Electno-Eiffage (Spanish and French based) to conduct LIDAR survey of the transmission line, Lot 1 from Yekepa to Buchanan and Lot 2 from Buchanan to Mano via Monrovia.
The aircraft has been inspected by the Liberia Civil Aviation Authority and has commenced the survey of the transmission line route. The survey allows mapping to determine both natural and man-made environments with accuracy, precision, and flexibility.
LIDAR stands for Light Detection and Ranging and is a remote sensing method that uses light in the form of a pulsed laser to measure ranges (variable distances) to the Earth. These light pulses, combined with other data recorded by the airborne system generate precise, three-dimensional information about the shape of the Earth and its surface characteristics.
A LIDAR instrument principally consists of a laser, a scanner, and a specialized GPS receiver. Airplanes and helicopters are the most commonly used equipment for acquiring LIDAR data over broad areas. LIDAR typically uses a near-infrared laser to map the land as well water-penetrating green light to measure seafloor and riverbed elevations.
In Sierra Leone, one of the EPC Contractors, KALPATARU has begun intensive soil testing within the transmission line corridors. They have dug several trial pits, an excavation of the ground in order to study the composition and structure of the subsurface.
Trial pits are usually dug during a site investigation, a soil survey or a geological survey. Trial pits are dug before the construction. They are dug to determine the geology and the water table of that site.