Open Pit Applications

The most common application for Yamamoto ultra-large rock splitter is open pit excavation or benching. This could be anything from foundations for buildings, metro station boxes, road widening to trenching.

Before splitting can be initiated, the rock has to be drilled for split holes. Drilling is done with a separate crawler drill.

The splitter is mounted on an excavator hanging from a wire. This allows the splitter to be lowered into the hole solely by gravity to ensure it is inserted in the correct angle. The splitter can also be mounted from a truck crane or telehandler and powered with a separate power pack.

The complete work process includes drilling, splitting, secondary breaking, and mucking out:


Drill the holes of Ø102 mm X 1.6 m depth for Yamamoto HRB-1000 splitter, or Ø127 mm X 2.5 m depth for HRB-1700 splitter using a large size hydraulic crawler drill or jumbo drill rig.

Spacing of holes depends on the rock hardness and availability to free face to split towards. The standard spacing is 500mm center-to-center for HRB-1000 and 700mm for HRB-1700. If the rock conditions are suitable this distance can be increased to allow for higher productivity.

The drilling pattern can be staggered or square and the holes can be drilled vertical or at an angle. This depends completely on the rock conditions and operator preference.


Insert the wedge into the hole and split the rock. Position the wedge so that it is splitting towards the free face. To maximize the splitter’s productivity, it is very important that the splitter is splitting towards a free face.

The splitting is done in three steps:
1st step: Insert half of the total length of wedge and operate the Yamamoto splitter to split.
2nd step: Then insert about ¾ of the total length of the wedge to split again.
3rd step: Finally, insert the total length of the wedge and split to complete.

Normally only the first three rows of holes can be split before the broken rock is cleaned out and the face is cleared.

Secondary breaking

Break the already split rock into smaller pieces and remove it with a conventional excavator with a rock breaker. Removing the broken rock will keep the free face close to where the splitter is working. There may also be a toe built up at the bottom of the face as the splitting progresses. This toe can also be broken out with the help of the rock breaker. Secondary breaking and splitting can be conducted simultaneously.


Remove the muck using hydraulic excavator, wheel loader or a similar machine.