The seismic refraction method has been found useful in prospecting for chromite in the Masinloc area.

Specifically, it enables the prospector to determine rapidly and at low cost whether or not an observed chromite ore outcrop is part of a. larger, buried ore-lens and in which direction this lens trends relative to the outcrop.

In these tests a. seismic timer was used. This instrument is relatively cheap and the actual prospecting can be carried out by a technician assisted by two or more laborers. The prospecting technique is described; its principal limitation is its inability to distinguish between chromite ore and gabbroic dikes.