Archive for November, 2009
Casing Drilling Under Structure
Posted by: | CommentsFeature Article
Kodiak Drilling is routinely involved in drilling projects to solve non-routine drilling problems. As the company specializes in limited access areas, solving a problem of how to get the drill to the borehole location and complete the required work program is a daily challenge.
A recent project was presented that involved drilling in an underground parking garage. The location initially did not present a problem as many projects have been completed in parking garages. The combination of the additional constraints presented below however, looked like they were going to be impossible to overcome:
- Borehole depth requirement of 40-50ft (~12-15m),
- Overhead clearance of approximately 7ft (2.1m),
- Requirement for Standard Penetration Tests (SPTs),
- Firm silt till materials, overlying unstable flowing sands below the water table, and
- Use of hollow stem augers was not permitted due to the potential for structural disturbance of the sand formation.
Together with the geotechnical engineering consultant and colleagues at Walker Drilling (who worked together with Kodiak on this project), a method was developed to overcome these obstacles. The primary components of the developed method include the following:
- A Big Beaver drill was used with the tower removed from the drill to allow access to areas with restricted headroom. Extended hydraulic hoses were used to allow the machine to operate without exhaust fumes within the confines of an indoor environment.
- To overcome the issues of depth and a requirement to limit the disturbance to the sand formation, the drill head was used to rotate BW size drilling casing, with a cutting shoe at the base of the string. Given the short stroke available, fabrication of custom casing lengths was required before starting the project.
- In order to prevent blow-back of the heaving sands into the casing, the interior of the casing was pressurized (through a swivel), with a dense, viscous drilling mud.
- As a traditional recirculation mud pit could not be accommodated within the low overhead environment, a vacuum extraction system was employed for retrieving the expended mud/cuttings mixture. A mud pump, operating from an auxiliary hydraulic power unit, provided the mud solution to the casing string, while the vacuum system returned it to a recirculation tank.
- The remaining problem to be overcome was the requirement for SPTs in an area lower than the 8ft minimum requirement for this drill. This issue was overcome by using a manual slide hammer to advance standard split spoons through the hollow casing. The requirement of 300-400 blows per foot in some areas made this aspect particularly challenging for the site crew.
Operation of the casing, the manual hammer, the mud pumping system and the vacuum recirculation component required a large crew, working in off-hours to minimize the impacts to the ongoing garage operations. By the end of the project, several boreholes along with piezometer installations were completed to a depth of 48ft.
Although the casing/washboring method is commonly used by larger rigs in unlimited access areas, the confines of this site made this seemingly impossible project possible with unique limited access equipment and teamwork.
I Don’t Need a Private Locator – It’s Only a House
Posted by: | CommentsKodiak Drilling – Feature Article
Why does Kodiak insist on having private locates done at most houses? That question can best be addressed by relaying the stories told within a recent TSSA press release related to deaths and injuries at two homes.
“On July 30, 2008, a residential explosion in Niagara Falls killed one occupant and injured another when a landscaper drove a bar into the ground, installing a “rail tie” wall. The bar punctured a propane service line, running from the home to a pool heater, and the escaping gas migrated to the residence. The gas built up to an explosive level, and found a source of ignition.”
The story is discussed in two press reports below:
Read the Niagara Gazette Article Here
A portion of the second press story is below:
While investigators have determined a cause, there are many unanswered questions. The most significant being why the landscaping crew didn’t call someone to locate the service lines before they started hammering rebar into the ground. “It’s up to the contractor to call in before digging.” (Brian Biggins – Niagara Falls Fire Department) Contractors are obligated to call a organization known as ‘Ontario One Call’ before they put anything into the ground. “They do all the ground locates for all services.”
Unfortunately this is somewhat misleading, as the propane lines were owned by the homeowner and therefore the locators dispatched by Ontario-One-Call member utilities would not have located this propane line. Only a private locator would have prevented this tragedy.
The second incident occurred in September 2008; a man was killed while his wife was injured in an explosion in their home in East Linton Ontario. The story is described in the following press article:
A key quote from the article: “…..the excavator, is also charged with failing to ask the owner to locate and mark his services. That company is charged as well with failing to protect the worker by ensuring that person knew the propane line was there”.
This highlights the potential liability of Kodiak Drilling and our client consultants for not having the owner provide the information about private services. Providing that information is normally done by contracting a private locator to review the property. This liability pales in comparison to the tragedy of an injury or death of a driller, consultant, or homeowner.
In nearly all cases, in addition to Ontario-One-Call, a private locator should be contracted for a residential project. Private services can include pool heater and water lines, communications lines for TV towers or satellite dishes, electrical lines for landscaping or pool lights, electrical cables or water lines leading to sheds or detached garages, BBQ or gas fire pit lines, and infra-red heater lines, among others. Relying on a home owners memory of where they “think” the lines are located is not a suitable alternative to proper locates, from either a legal or safety perspective. If a Kodiak driller observes any services such as those above, their pre-drill safety inspection process prevents them from undertaking any drilling. Our benefits plan does not cover funerals !
Kodiak Drilling specializes in drilling in limited access areas and therefore completes projects at private residences on a regular basis. Our drills are particularly well suited to providing minimal disturbance to front lawns and accessing backyards by traversing walkways, driveways, steps, fences and gates. Many of these projects relate to geotechnical investigations for foundation and footing designs, slope stability studies, retaining wall designs, and home additions. Other projects are for environmental consultants conducting assessments at homes related primarily to heating oil contamination problems or issues of offsite migration of contaminants from a neighbouring property.
The full press release can be viewed at the TSSA website; October 16, 2008, Reference No. FS-140-08.
Drilling Is Not Dangerous
Posted by: | CommentsFeature Article
There is a saying that goes like this: Drilling is not dangerous; it is potentially dangerous. There are many potential dangers faced by personnel working on and around drilling equipment. Personnel in this sense includes drillers, helpers, field sampling staff, site occupants, and the general public. One of the most substantial dangers to all of the above mentioned parties in a drilling project, are the risks associated with underground utilities. Utility issues are so important to the work of drillers, there is a standalone section on the website along with articles and blog posts on this topic in other areas of the website. Besides requiring utility locates, what other measures are required to ensure the safety of drillers and the other stakeholders mentioned above?
One of the common methods used by (some) drilling and consulting companies to reduce the potential dangers, is the completion of a pre-start meeting, commonly called a “tailgate safety meeting”. These meetings vary in format, but are generally developed in-house by company health and safety personnel, and are generally designed to achieve two main objectives, 1) to make sure that all site personnel are thinking about the safety aspects of all the tasks they are completing in the upcoming site work, and 2) to ensure that all personnel are aware of the site specific hazards that may be encountered at the job site.
As there are no standards for the content or format for such meetings and the quality of the analysis required to complete a tailgate meeting vary widely among companies, Kodiak Drilling undertook to establish a new protocol for completion of tailgate safety meetings. The development of this new protocol was undertaken with two guiding principals, 1) the process must be comprehensive enough to address many expected and unexpected site safety issues, and 2) be streamlined enough to be completed quickly so that it does not significantly impact on our ability to complete the site work expeditiously.
Achieving either one of these objectives would be easy, but achieving both required the development of a unique system. The system that was developed has two components:
Tailgate Safety Checklist: This is one piece of paper that is completed at each job site. It is a checklist style form that covers topics within each component of the analysis:
- Project Information and Emergencies
- Identify Hazards and Concerns
- Utility Clearances
- Personal Protective Equipment (PPE)
- Safety Equipment
- Traffic Control
- Equipment Inspection
- Safety Plan Acknowledgement
- End of Project Meeting
- End of Project Sign Off
Health and Safety Plan – Field Work: This document discusses each of the above listed ten components and provides the necessary information for site personnel to complete the site specific analysis.
When the Kodiak Drilling crew arrives at the work site, they will complete this process with the other project staff. All site personnel should be familiar with the results of the site specific tailgate assessment, in order to ensure that the drilling is not dangerous.
Kodiak has raised the bar when it comes to tailgate safety checklists, but hopefully others will follow suit and improve the process for everyone involved in undertaking drilling projects. The tailgate safety meeting process undertaken by Kodiak Drilling is only one component of the company Health and Safety Management System. For more information on this system, please do not hesitate to contact us.
Basement Drilling
Posted by: | CommentsFeature 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.
300,000 Commuters !!
Posted by: | CommentsTTC Subway Damage
It would not be a pleasant experience today, to be the contractor that undertook the excavation work that caused the damage to the subway tunnel yesterday. Although it is in the early stages of the investigation, it is obvious that someone was digging in a place where the subsurface utilities (tunnel) were not adequately identified. It will be interesting to see if the contractor had “complete locates”. Regardless, no matter what locates they had (if any) were certainly not adequate. It will also be interesting to find out if the excavation contractor is liable or the engineer/project manager or both.
Some excerpts of a Globe and Mail story are below:
A construction accident by a third-party contractor working for Enbridge forced the TTC to close part of the Yonge subway line during the evening rush hour Wednesday, stranding some 300,000 commuters. The route was shut down between Bloor and Eglinton stations for about six hours before opening last night around 8:30 p.m.
The service interruption was the result of damage caused by a construction crew that was cutting a trench on Jackes Avenue, which runs over the underground subway tracks south of St. Clair Avenue. The contractor, identified as Link-Line, was relocating an Enbridge natural gas pipeline. In the process, they cut through the street and into the subway tunnel.
“Initial reports indicate that it is something that could have been prevented with a little more know-how or preparation,” said TTC spokesman Kevin Carrington. “We really don’t know at this point why it happened, but we know that this crew was working on it, so right now the blame seems to be falling on their shoulders. Definitely it was not the TTC’s fault.”
TTC officials are considering whether to recover costs associated with the disruption, such as staff overtime, from whoever was responsible for breaching the tunnel.
“Money’s a big issue right now, and time and safety is a big issue. So eventually I think it’ll have some sort of quantitative value, so to speak,” Mr. Carrington said.
Debbie Boukydis, an Enbridge spokeswoman, said the company is co-operating with the TTC, the City of Toronto and the provincial Labour Ministry as they investigate the mishap.
“In terms of finger pointing at this time, that’s why these investigations are so important to make sure that we are able to determine exactly what happened. Number one, to learn from any mistakes, if that was the case, but also to assess what happened and who actually was at fault,” she said.
Ms. Boukydis said Link-Line was working for Enbridge and was performing an emergency relocation of a natural gas pipeline at the city’s request. Such work is closely co-ordinated with city officials, she said, including obtaining permits and determining the location of road cuts. The work started last Friday and was to have wrapped up by weeks’ end, but is now on hiatus.
The accident damaged a 22-metre long, 42-cm deep concrete slab. A small amount of debris fell onto the tracks. The TTC shut the line because it wasn’t safe to run subway trains because of the vibrations the fast-moving trains might create, fearing a worst-case scenario of a cave-in or tunnel collapse.
Field Equipment Available
Posted by: | CommentsOne of the often overlooked advantages of Kodiak Drilling, is our inventory of field equipment that is available to our clients. This equipment is not normally in the drill trucks, but can be brought with the drill crew (upon request), to sites for our client personnel to use (at no cost of course).
This equipment includes:
- PID
- GPS
- Hand sampling kit
- Water level and interface meters
- Roll-a-tape measuring wheel
- Laser range finder
- Metal detector
- Hand held soil vapour probe
- Transit with tripod and survey rod
- Total Station with tripod and stick
- Peristaltic pump with battery pack
Asphalt Analysis
Posted by: | Comments
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.
Check out Case #3 in their Volume 9, Number 2 edition of Watson’s Notes
Gas Line Hit
Posted by: | Comments“Pavement tossed 50 feet in the air when drillers hit 4inch gas line”
The title of this post says it all !
Construction Safety Association (CSAO) Article
Posted by: | CommentsLocating Underground Utilities
In the Fall 2008 edition of Construction Safety Magazine, is an article on utility locates.
The most interesting part was on fines and penalties related to violations of the Construction Regulation:
“an individual can receive a maximum fine of $25,000, a sentence of up to 12 months in prison, or both. A corporation can receive a maximum fine of $500,000″
This of course does not include the charges that the TSSA can lay.
There may be other articles in the magazine that are of interest to our clients. The article is on the second page of the document located here
For more information on utility locate issues as they relate to environmental and geotechnical drilling projects, please see other posts in this section and the locate tab in this website.
New 1-Call Features
Posted by: | Comments
This may be of interest to some of our clients – Ontario One-Call has developed a system to provide your work information to third parties (other utilities) to help you streamline your locate requests. This document also details method for you to get your work information in an excel format for your own records.