Safety 1st Advancer Manual do Operador descarregar pdf (Página 23)

Environmental Remediation Drilling

Safety Guidelines

Page 23 of 132

2.6.3 - Electromagnetic Utility Tracing Receiver

The electromagnetic technique locates buried materials having a high conductance. Alternating

electromagnetic waves generated at the surface are induced into the ground during the survey. When the

waves pass through a conducting body, they induce an alternating electrical current in the conductive

materials. These currents become the source of secondary magnetic fields, which can be detected at the

surface. The strength of the field is directly proportional to the average conductivity of the subsurface

materials. Typical electromagnetic applications include:

• Location of:

o buried pipes,

o tanks,

o drums and other metallic objects,

o sludge wastes,

o leachate plumes,

o salt water intrusions,

o acid mine drainage, and

o other ground water contamination problems.

Other applications include quick and economical site assessment of areas with variable bedrock topography,

such as those found in karst terrain, clay layer mapping, fault detection, or mine and quarry siting.

Figure 2.3 - An EM Tracer Being Demonstrated in a Non-environmental Remediation Work Area.

(Photo courtesy of Enviroscan, Inc.)

Limitations of this technique that can adversely affect the electromagnetic measurements include:

• Power lines

• Metal fences

• Metal debris, and

• Utilities

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