Safety 1st Advancer Manual del operador descargar pdf (Pagina 20)

Environmental Remediation Drilling

Safety Guideline

Page 20 of 132

2.5 - Selecting the Drilling Location

During the pre-fieldwork phase, determine the location and the type of drilling to avoid critical areas and

structures. Regulatory requirements and investigation objectives need to be considered in determining the

location and drilling types. For example, horizontal (directional) or angled drilling may be selected to drill

in a desired location to avoid potentially hazardous or critical zones (including high traffic areas). The

following is a list of questions the project team should ask when identifying a location, but note that this list

is not all inclusive:

• Does the location allow for clear entry and exit (unobstructed)?

• Is there adequate work space (vertical and horizontal)?

• Will pavement, curbs, or other structures need to be removed?

• Are all locations located outside critical areas?

• Have access agreements been completed?

• Have all appropriate permits been obtained?

• Have selected areas been reviewed for structures, overhead power lines, and critical items?

• Have borehole clearance procedures been completed?

Review and investigate the location selection with the client during an on-site visit. The determined location

should be identified on site maps and submitted to the facility, if required, in addition to the regulatory

agency for approval.

2.6 - Methodologies for Locating Private Structures

Due to specific site conditions, no single method of locating subsurface utilities is universally fail proof.

Surface and subsurface conditions may interfere with the effective use of a specific utility locating

technology. Following is a discussion of some technologies available and the relative merits of each.

2.6.1 - Ground Penetrating Radar

Ground penetrating radar (GPR) is an advancing technology used for investigating shallow, geologic, and

hydrologic features. The technique is also extremely useful in locating man-made features, such as buried

drums, tanks, pipes, or other metallic objects. Locating rebar in concrete or detection of voids beneath

concrete or asphalt is also a popular GPR application.

GPR operates on the principle that electromagnetic waves emitted from a transmitter antenna are reflected

from buried objects having different electrical properties than the host material. The signals detected at the

receiver antenna are recorded and provide a detailed cross section of the subsurface that is similar in

appearance to a seismic reflection record. The depth of penetration of the radar pulse is controlled by site

conditions and the frequency of the antenna chosen.

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Safety 1st Advancer Manual del operador Pagina 20