BoreHole Drilling Knowledge

In order to share our drilling knowledge to people who are interested in borehole dirlling. Here are introduction and application cases regarding water well drilling, geotechnical drilling, foundation drilling and minning exploration drilling. It also introduces the drilling method of rotary drilling, DTH(Down The Hole) Drilling and Top Hammer Drilling. The basic knowledge of drilling tools and rock are demonstrated as well.

We hope this kind of drilling knowledge could be helpful for our customers, friends and peers working in borehole drilling area.

One         Problem Worn bit head Probable cause Typical signs of back reaming to remove the hammer from a collapsed hole Corrective action Improve flushing, more air Use water or foam in flushing air to stabilize the hole Two         Problem Bit striking face damage Probable cause Difficult to find signs causing this damage, but most probably wrong type of tools have been used to remove the foot valve when replaced Corrective action Use correct tools (foot valve puller) Three         […]

Hammer Piston Casing Breakage and Tread Breakage have been demonstrated in former article, today we will show you some cases of Hammer Piston broken. Case 1          Problem Galling Probable cause The signs of wear and streaking indicate that galling is the cause of this breakage that has occurred shortly after another piston breakage in the same hammer Corrective action Make sure that piston casing is polished or honed before a new piston is installed Case 2            Problem Broken piston […]

The problem of Thread broken has been introduced in Down The Hole Drilling Trouble Shooting – Treaded,  and in article we will try to explain what caused hammer piston casing breakage and how to fix it. Piston Casing – Case 1            Problem Longitudinal crack on piston casing Probable cause Loose joint Insufficient make-up torque […]

General This chapter contains some common types of failures occurring on DTH drilling tools For most failures we can identify it’s probable cause and typical supporting evidence Corrective actions to avoid recurrence of the failures are also described Number 1              Problem Lower end thread failure due to fatigue cracking at the root of the first engaged thread near the base of the pin Probable cause No evidence of contact between the shoulder of the box thread and the pin indicates that the thread has not been made up correctly Corrective action Check for proper make up of threads before drilling starts Number 2         Problem Upper end thread failure due to bending stresses Probable cause […]

In the former article, the Down the Hole and Top Hammer Drilling method was introduced. Today we will explain more on rotary drilling method Rotary Drilling Fundamentals Rotary drilling is a versatile method for blast hole drilling. It is the dominant method for holes larger than 203 mm (8”) diameter. In smaller holes, it is […]

Here we will give the high level introduction on how to select the DTH drilling tools, due to they are the key components for borehole drilling. Hammers and bits Generally the hammer should be selected to match the maximum operating conditions for the compressor The recommendation is that the hammer shall use about 85% of the compressor air delivery capacity The bit should be selected to give best possible drilling rate and service life in present rock conditions Bit face and head design Flushing holes […]

What is Cemented Carbide? A powder metallurgical material A composite material comprising hard particles embedded in a binder phase. The hard particles are Carbides like WC, TiC,TiN The binder phase is Cobalt, Nickel or an alloy For Rock Tools grades WC – Co is used. Cemented Carbide inserts         Applications Top Hammer […]

How to Repair Drill Bit

February 11, 2018

General In article DTH Drilling Care & Maintenance – Part One and DTH Drilling Care & Maintenance – Part Two , we introduced how to correct balanced system, causes of product failures and the importance of lubrication. Here we will explain the importance of regular repair bit and how to do it Service life for rock drilling tools is […]

Drilling Methods There are four different drilling methods to select from: − Rotary wearing − Rotary cutting − Rotary crushing − Top hammer percussive − Down the hole percussive Rotary wearing − Rotary wearing method’s application is normally for sampling for geotechnical exploration. −  Drill bit is made of a couple of 3-edges, 3-edges consist outer edge, middle edge and internal edge. Every edge only take one […]

General In chapter DTH Drilling Care & Maintenance – Part One, we introduced following topics: A balanced system Correct drilling parameters Most common causes of product failures Corrosion Fatigue Galling In this chapter, the discussion will be continued and following items will be explained: Lubrication Hammer disassembly Drill pipes Lubrication Correct lubrication during DTH drilling is extremely important Inadequate lubrication is a major cause of hammer wear and failure Excessive lubrication slows down the […]