Excavating machines shall not be used where unstable conditions or slopes of the ground or grade may cause such machines to tilt dangerously. To prevent such unstable conditions, mats of timber or equivalent means to afford stable footings shall be provided.

Where an operator of an excavating machine may be exposed to an overhead hazard, such equipment shall be provided with a cab or equivalent cover affording protection against such hazard.

Excavating machines shall be operated only by designated persons. No person except the operating crew shall be permitted on an excavating machine while it is in motion or operation. No person other than the pitman and excavating crew shall be permitted to stand within range of the back of a power shovel or within range of the swing of the dipper bucket while the shovel is in operation. When an excavating machine is not in use, the blade or dipper bucket shall rest on the ground or grade. The operator of an excavating machine shall not leave the controls of such machine at any time when the master clutch is engaged and the engine is operating. Oiling and greasing shall be performed only while an excavating machine is at rest and the master clutch disengaged. The boom or the bucket, dipper or clamshell of a power shovel shall not pass over the seat or cab of a truck or other vehicle while any person is in such seat or cab.

The operation of excavating machines near power lines or power facilities shall be in compliance with this Part (rule).

Material shall not be pushed manually into the path of trenching machines.

The operator of any excavating machine shall not leave the controls of such machine until he has lowered the bucket or blade into firm contact with the ground or grade surface.

Every mobile power-operated excavating machine except for crawler mounted equipment shall be provided with an approved warning device so installed as to automatically sound a warning signal when such machine is backing. Such warning signal shall be audible to all persons in the vicinity of the machine above the general noise level in the area.