User Manual

Introduction 5
In addition to uncovering utility lines, dry excavation was tested in
several applications during the 1970s and 1980s. This included work
with the Department of Defense to uncover landmines and unexploded
ordnance, as well as “trenching” for construction. Improvements in
equipment included advancements in AirSpade nozzle technology
to provide faster excavation.
By the mid-1990s, dry excavation technology also became common
within the arboriculture industry, as this same technology was
applied to uncover sensitive tree roots without harm. As tree-service
companies began to recognize the advantages of this diagnostic tool,
many new, low-impact arboricultural applications were developed.
Bartlett Tree Experts, the largest US tree-service company, became
an early adaptor. At this same time, experiments with high-pressure
water led to advancements in hydro excavation.
Typical repairs using dry and hydro excavation came to include cast
iron main joint repair, sacrificial anode instillation, low-pressure service
cut-offs, new service instillation, and valve box replacements. In
addition to utility maintenance, these processes have direct application
to other underground operations such as test holes, service drops and
shallow slice pits for the telecom industry, daylighting and test holes
for directional drilling, and inspection holes for pipeline integrity and
Subsurface Utility Engineering (SUE).
Today, countless gas distribution companies and their contractors in
North America practice keyhole technology using rotary coring, soft
excavation, and core reinstatement. This process achieves average
savings of almost $1,000 per repair vs. conventional methodologies.
In a recent paper, the Gas Technology Institute reported that over
800,000 utility roadway cuts are made per year. Given the inherent
safety and cost advantages, the use of soft excavation for trenching,
potholing and keyholing is projected to grow significantly over the
foreseeable future.