HOLLOW STEM AUGERS

INTRODUCTION

Since Foremost Mobile introduced hollow stems in 1954,

their focus has changed to a more environmental concern.

Innovative design, state of the art engineering and

manufacturing processes make Foremost Mobile the

recognized industry leader in hollow stem augers and

related accessories.

Using Hollow-Stem Augers

The hollow-stem auger is used to advance and case the

hole simultaneously. It may be used with or without a plug

assembly depending on the job requirements. When a

plug is used for the purpose of keeping soil from entering

the mouth of the lead auger, it is held in place by center

(drill) rod and rod to cap adapter, pinned in the drive cap..

Upon reaching the sampling depth, the center rod with plug

and pilot bit attached is removed from the mouth of the

auger and replaced by a solid/split barrel soil sampler or

tube sampler, lowered to the bottom of the hole through

the hollow stem of the auger and sampling or coring is

initiated.

The use of a hollow-stem auger without the plug has

shown that most clay type material will form its own 2"- 4″

(51—102mm) plug which can be driven or washed through

for sampling or core barrel operations. When flowing

sands are encountered, mud may be added inside the

hollow stem to serve as a “head” to equalize the

hydrostatic pressure in lieu of the plug assembly.

Hollow-stems are rotated dry and often to depths of 300

feet (91.4m). Many special applications can be carried out

in addition to full range soil sampling. Piezometer and well

point placement, slope indicator placement, cathodic

protection devices, water wells, ground water monitoring

wells, diamond drilling, anchor bolt placement as well as

grouting and blast hole loading are some of the jobs that

hollow-stem augers facilitate.