Environmental – Page 6

Feature Article

Over 15 years of experience conducting drilling investigations in limited access areas, has led Kodiak to develop an array of methods for accessing and drilling very complicated locations. Many of these methods have been developed as a result of a challenge presented by clients. A very typical phone call to the office would sound something like this: “…….and these holes are located in a yada yada yada spot that there is no way we can fit a truck mounted drill into……I have called every driller I know and they all say they cannot do it…..” In the mid 1990s, these challenges led Kodiak to alternative equipment that was not within the fleet of a conventional drilling company. Over the last several years the focus has been on tweaking these machines and developing alternate methods and various tricks to push the machines to more far reaching limits. It has now reached the point where a client can mention virtually any type of location and Kodiak will likely have a proven method (that is not to say however, that new challenges are not welcome).

Kodiak pioneered the Big Beaver drilling method in Ontario in 1996; a method specifically developed for fly-in locations in Northern Ontario. Since that time, many variations on the method have been developed and implemented at a number of sites. While drilling indoors with the machine has been undertaken countless times, it has increasingly been used to access basement locations by winching the machine down interior staircases.

Some recent challenges have taken this method to new limits. A recent job highlights some challenges presented by a number of projects undertaken over the last few years:

The boreholes and monitoring well locations were in three very small basements of a strip plaza with a narrow rear alleyway and operating businesses,

Other drillers, using rapid percussion methods were unable to advance the holes to sufficient depths due to the soil conditions,

All holes were to be large enough to install 2inch monitoring wells to facilitate hydrogeological testing in addition to the contaminant sampling,

All drilling was to be undertaken using hollow stem augers, preventing the usage of a small probe type of drill.

Overhead clearance was approximately 7ft (2.1m),

And most significantly, the interior configuration of the building units and stairways would not allow for a Big Beaver to be winched into the basements.

As rapid percussion equipment alone was not suitable for the project, the only way to fulfill the mandate was to disassemble the Big Beaver, carry it down the stairs in pieces, and reassemble it in the basement. This has presented a significant challenge on similar projects, as the machine is not only structurally assembled, but also contains three hydraulic motors and an array of fittings and hoses. Once disassembled, the largest piece of the drill is still over 250lbs and a challenge to manually carry down the stairways. Key to this process was the ability to complete the disassembly and reassembly process in a tight time frame in order to keep drilling costs down and minimize the disturbance to the tenants. Kodiak has made a variety of modifications to the drill so that the tear down and rebuild may be done quickly.

Once in the basement and the drill reassembled, drilling was completed by using a combination of hollow stem augers with the Big Beaver and a PEP (Portable Electric Percussion) drill for soil sampling. The PEP was needed as the restrictive overhead clearance did not allow for the use of the cathead and 140lb hammer component of the drill.

Of course once the drilling was completed, the disassembly process needed to be repeated in order to move the drill back out of the basement, moved to the next basement and then reassembled. This process was repeated for each of the units where drilling was required.

For more information, contact Kodiak Drilling, the limited access specialists for environmental and geotechnical drilling in Ontario.

Periodically, when we are undertaking drilling for our environmental consultant clients who are undertaking contaminant investigations, we encounter waste asphalt in the split spoon samples we provide or in the auger cuttings exiting the borehole. When undertaking an investigation for petroleum hydrocarbons, does this material interfere with the investigations? Is this material soil as defined by the MOE Standards? Are the analytical techniques used appropriate for this material? A recent article produced by Investigative Science Incorporated (ISI) in Burlington discusses the analytical issues.