| Use: | Sonic drilling is used for continuous sampling and monitoring well installation in unconsolidated and soft/fractured bedrock. The primary benefits of this technology are that very rapid drilling rates are possible combined with reduced volumes of secondary waste. Recent improvements in equipment design should lead to increased use in the future. |
Description:
A sonic rig uses an oscillator or head with eccentric weights driven by hydraulic motors to generate high sinusoidal force in a rotating pipe drill. The frequency of vibration (generally between 50 and 120 cycles per second) of the drill bit or core barrel can be varied to allow optimum penetration of subsurface materials. A dual string assembly allows advancement of casing with the inner casing used to collect samples. Small amounts of air and water can be used to remove the material between the inner and outer casing. When a drill bit is used, most of the cuttings are forced into the borehole wall. A thin-wall or split-spoon sampler can be used to contain continuous samples. Sonic drilling is also referred to as vibratory drilling and rotosonic drilling.
Analytes:
| 1. Non-Halogenated VOCs | 5. PAHs | 9. Inorganics |
| 2. Non-Halogenated SVOCs | 6. Pesticides/Herbicides | 10. Explosives |
| 3. Halogenated VOCs | 7. Metals | 11. TPHs |
| 4. Halogenated SVOCs | 8. Radionuclides |
Media:
| Soil: | Ground Water: | Surface Water: | Gas/Air: |
| MINIMUM | MODERATE | Not Applicable | MAXIMUM |
Collection of continuous, relatively undisturbed unconsolidated and bedrock cores possible.
| Maximum Depth: | <500 feet. |
| Production Rate: | Sample is available quickly. Higher drilling rates than conventional methods (around twice as fast as air rotary and 8 to 10 times faster than hollow-stem auger and cable tool). This method is slower than mud rotary, but does not generate significant quantities of waste to be disposed of when working in a contaminated environment. |
| Investigation Derived Waste Volume: | Small volume of waste. Produces about one-tenth the cuttings of a hollow-stem auger or cable tool. |
| Technology Status: | Commercially available technology with moderate field experience. |
| Certification/Verification: | Technology has not participated in CalEPA certification and/or CSCT verification program. |
| Relative Cost per Sample: | Most expensive. Higher operation, maintenance, and tooling costs compared to conventional drilling methods. |
Limitations:
ASTM Standards/EPA Methods:
No applicable ASTM standards or EPA methods are cited for this technology.
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