Geotechnical investigations differ from diamond drilling in many ways including the goal of the investigation as well as the issues drillers must keep in mind.
1) Keep safety in mind
In the world of geotechnical and environmental drilling, the drill site is often found in the middle of a busy urban center, on public roads, near bridges and overpasses, on school grounds, shopping malls, gas stations, or in the middle of a busy intersection. The dynamics of this kind of drill site are very different from the typical diamond drilling site.
2) Avoid contamination
Environmental drilling often involves analyzing soil conditions to determine what contaminants may be in the soil and groundwater and to define the severity of the contamination. Continuous sampling is an effective method used to gain an undisturbed representative sample which will help to determine the extent of the contamination within a borehole. The goal is to obtain a complete record of the soil beneath a drilling site and identify more permeable soil zones that can be pathways that allow contamination to migrate.
When soils are tested for contamination, parts per million (PPM) is the measurement used to measure the amount of a contaminant. As this is a very precise measure, the cleanliness of the sampling equipment, including the augers, casing, drill pipes, and hammer equipment is extremely important. Any equipment must be ultra-spotless and free of any dirt from previous drilling jobs. In addition, the sampling equipment should be cleaned after every use, meaning that once you have finished one hole, you need to decontaminate the augers, split spoons and other equipment.
If the environmental tests from the laboratory indicate the samples obtained contain harsh contaminants, then the soil drums you use will have to be transported to a facility that specializes in the treatment of contaminated soils. In these cases, the water to clean the equipment would have to be contained as well.
3) Return the site’s condition
When drilling in the city, drill sites must be returned to the condition they were in before the drilling operation began. A pressure washer is an excellent tool for hosing down sidewalks, roads, parking lots, along with a broom to sweep. Of course, any holes made by the drill rig must be finished with asphalt patches, or concrete.
Depending on the type of ground you encounter, you may have other specific issues to deal with such as drilling in abrasive rock or sandy ground, or problems drilling in overburden, but rest assured that solutions exist for most of the issues you’ll encounter.