Komatsu Ltd., the world's second-biggest maker of mining equipment, is going underground.

The joint venture with General Electric Co.'s mining arm announced on Jan. 29 and set to begin in April will be the first step in Komatsu's foray into the market for subterranean mining equipment, Senior Executive Officer Kazuhiko Iwata said in a recent interview at the company's Tokyo headquarters.

Komatsu's absence from the market has prompted speculation that it would acquire a rival already active in the field. The Tokyo-based company, the first to offer driverless dump trucks, as well as hybrid excavators that use technology similar to that found in Toyota Motor Corp.'s Prius car, may buy technology instead, Iwata said.