Reverse Circulation Drilling Hammer Bit

Choosing the Right RC Hammer

Leanoms has a comprehensive range of Reverse Circulation hammers that are capable of drilling exploration and grade control holes from 84mm up to 370mm.

Generally, the correct hammer to use is determined by the sample weight per meter drilled that the mine or geologist is looking to achieve. The set-up of the hammer to achieve the most efficient penetration rate and sample quality is very important and will vary depending on a number of different factors. The factors to consider and the variation in setup is as follows.

Air Package

The size of the compressor being used will decide whether or not to use the standard hammer setup or the low-air setup. 

Alternatively, it may be prudent to opt for the next size down of the RC hammer where there is usually some cross-over in drill bit sizes between each of the RC DTH Hammer.

The low air term used in the RC range is not to suggest that the hammer can only be used on lower-volume compressors. The design is most beneficial when there is no booster available and drilling is done with only the compressor on the drill rig. The other benefit of this design is when drilling at higher elevations the engine and compressor performance will be hindered due to the effect of altitude on compressed air. 

Retention

The retention head design on drill bits is available when drilling deep holes where there is an increased risk of shanking the head of the drill bit. The threaded head retention system will retain the bit head if it shanks off at the end of the splines and the head can be returned to the surface and not left down the borehole.

Sample Tube

All hammers are assembled with the larger bore size sample tubes unless the customer requests the smaller bore size at the time of order. The larger bore sizes are a more versatile option in different drilling conditions. In a deep hole drilling application the larger bore the size will allow the hammer to drill deeper under a head of water, as this design deals with the effects of back pressure better. Grade control applications are generally where the smaller sample tube bore size helps and where the bit size is not excessive. The greater wall thickness of the tube can give better tube life in high abrasion applications.