HL820ST is a hydraulic top hammer rock drill, specially designed for DL311 and DL321 underground deep hole drill

HL820ST hydraulic rock drill is designed to ensure high drilling capacity, easy maintenance and low operating cost. The structure of the rock drill is based on the main module bound together with four short side bolts; This ensures a minimum number of joint surfaces and large contact surfaces. The impact module is simple in design and consists of only two moving parts: the piston and the distributor sleeve around the piston. The moving parts do not contact with the rock drill body module.

The HL820ST is equipped with a bit stabilizer that adjusts impact power in response to changing rock conditions, ensuring good rock-bit contact and energy transfer, improving drilling rate and rock tool life.

There are two rotary motor variants to meet rotary torque and RPM requirements for different apertures and rock formations. Optional power extractors are used to manually or automatically open rock tool joints when using single hole or fan automation. The HL820ST design is covered a number of patents.