1. Environmental Drilling By: Josh Humphreys October 10,2006

2. Recap!! Why do we drill? What types of thing are we looking for when we drill? What machinery types or equipment do we use?

3. Selection of Drilling Methods Selection of Drilling Methods Selecting drilling methods for environmental investigations is typically a process of evaluating trade-offs. Selecting drilling methods for environmental investigations is typically a process of evaluating trade-offs. Some methods allow for quick drilling of wells but may be poorly suited for rock or soil sampling. Some methods allow for quick drilling of wells but may be poorly suited for rock or soil sampling. Mineral exploration vs. Monitoring well Mineral exploration vs. Monitoring well

4. Health and Safety Sites may be potentially contaminated. Sites may be potentially contaminated. Contamination levels are often unknown prior to drilling. Contamination levels are often unknown prior to drilling. Need a site specific health and safety plan( Chapter 19 Handbook) Need a site specific health and safety plan( Chapter 19 Handbook) Cuttings produced must be handled, and cutting fluid must be disposed of safely. Cuttings produced must be handled, and cutting fluid must be disposed of safely. Fire and explosions possible from auger and sonic drilling due to high heat. Fire and explosions possible from auger and sonic drilling due to high heat.

5. Access and Noise Drill in connection with environmental investigations is frequently carried out in urban areas. Drill in connection with environmental investigations is frequently carried out in urban areas. Most drills are mounted on trucks, limited maneuverability. Most drills are mounted on trucks, limited maneuverability. Must consider area: power plant, refinery, side-to-side and over head clearance. Must consider area: power plant, refinery, side-to-side and over head clearance. Time of day, noise ordinances, residential complaints. Time of day, noise ordinances, residential complaints.

6. Disposal of Fluids and Cuttings Very important in selection of drilling method. Will it be fluid or earth? Very important in selection of drilling method. Will it be fluid or earth? If heavily contaminated may be handled as hazardous waste. If heavily contaminated may be handled as hazardous waste. Will as significant cost to project to obtain license from special site. Will as significant cost to project to obtain license from special site. Direct push and sonic drill produce no cuttings and are useful alternatives. Direct push and sonic drill produce no cuttings and are useful alternatives.

7. Lithology and Aquifer Characteristics Certain drilling methods are better suited than others. Certain drilling methods are better suited than others. Augers- Augers- Good- unconsolidated and semi consolidated material, relatively dry conditions Good- unconsolidated and semi consolidated material, relatively dry conditions Bad- Consolidated bedrock, water table drilling, loose, flowing or blowing sands. Bad- Consolidated bedrock, water table drilling, loose, flowing or blowing sands.

8. Lithology and Aquifer Characteristics Cont. Air and mud rotary drilling- Air and mud rotary drilling- Good- Can advance through most materials, fast and effective. Good- Can advance through most materials, fast and effective. Bad- more waste to dispose of when finished, potential to pollute, Drill more blindly less knowledge of layers as the bit passes through, advances more than a few feet without circulation could get stuck. Bad- more waste to dispose of when finished, potential to pollute, Drill more blindly less knowledge of layers as the bit passes through, advances more than a few feet without circulation could get stuck.

9. Depths to consider Rotary methods can go to depths of several thousand feet. Rotary methods can go to depths of several thousand feet. Auger drilling is effective up to 150ft. Auger drilling is effective up to 150ft. Hollow stem auger up to 400 ft. Hollow stem auger up to 400 ft. Bucket auger less than 100 feet due to length of Kelly bar and caving potential Bucket auger less than 100 feet due to length of Kelly bar and caving potential Sonic Drilling is less cost effective for shallow hole b/c of setup, effective 50-300 and up 700 for favorable conditions. Sonic Drilling is less cost effective for shallow hole b/c of setup, effective 50-300 and up 700 for favorable conditions.