One question we get frequently from our clients is: how accurate is underground utility locating? The alternate question is: what's the safe distance to drill or excavate away from marked underground utilities? Although there is no precise answer to this question, there are still some good practices to follow. Some states require you keep certain distance away from marked underground utilities if powered tools are to be used. For example, in new jersey, you can only hand dig within two feet of a line marked by utility companies. In general, two feet is the minimal distance. but most companies doing drilling or excavation routinely have formed their own policies and 3, 5, or even 10 feet dist
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Enviroprobe recently purchased a Dando SDC375 Roto-Sonic drilling rig equipped with the Sonicor 50K drill head. It is a multipurpose sonic drilling rig capable of continuously collecting large diameter undisturbed samples at much higher rates than conventional drilling methods. Its compact and powerful design, featuring the industry leading Sonicor 50K rotary head, offers great flexibility for a range of drilling applications including mineral, water, geotechnical and GSHP. The sonic drilling rig is a powerful machine with a small foot print allowing it to operate in area of limited space. It is outstanding in its ability to provide continuous, undisturbed core samples through any geological
Enviroprobe recently conducted soil resistivity testing with Wenner Array 4-point Method at several sites in central and north New Jersey. This method is the most commonly used test method to measure the resistivity of soil for electrical grounding design. The Wenner array consists of a line of four equally spaced electrodes. Current is injected through the outer electrodes and potential is measured between the inner electrodes. The testing utilized an Advanced Geoscience Inc. (AGI) SuperSting R8 resistivity system and was done in a perpendicular pair at each testing location using the standard traverse setup with the maximum “a” spacing as 100'. For accurate results, testing locations shoul
When there is a good penetration depth for ground penetrating radar (GPR), GPR can be used to estimate thicknesses of subsurface layers. However, caution has been taken as such estimation may not be accurate without references or ground truth information. As EM waves from GPR travel down and bounce back from a subsurface interface between two layers, the travel time can be determined. In order to calculate the depth to the interface, the wave travel velocity needs to be known. Although there are indirect ways to estimate the wave velocity and depths such as using the common midpoint (CMP) method, the most direct and accurate way is to get the ground truth. The ground truth collected at one o