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SUBSURFACE LANDFILL FIRE
SUPPRESSION AND MONITORING
A Case Study at the Campbell
Mountain Landfill, Penticton, British Columbia
The Drilling
Program.
There are several special safety considerations that apply when
drilling on a landfill site. Since there was also an underground
refuse fire, the number of special considerations increased. Some
of the most important considerations included:
- Ground conditions may contain
cavities that can give way under the weight of a drill rig.
- Methane gas is explosive between
5-15% by volume, which is well within a typical concentration
range found in landfill sites (40-60% by volume).
- Hydrogen sulphide and carbon
monoxide, which were both detected at the site, are toxic at
sufficient concentrations.
In order to provide a flat and stable
working base for the drill rig, a construction firm who was familiar
with the design and construction of roadways under similar conditions
was retained to install a series of access ramps along the face
of the north ravine. The thickness and design of the access ramp
pad was sufficient to support a truck mounted drill rig. The application
of the material was accomplished by pushing the material from the
top of the ravine, rather than by directly dumping the loads onto
the work area, as the load distribution of a wide track dozer is
substantially less than that of a truck.
A auger rig was used to execute
the drilling contract because they have the lowest risk of creating
sparks that can ignite the venting methane gas, and unlike air
rotary rigs, they do not inject air into the refuse. High volume
ventilation equipment was used in the working area in order to
dilute any methane emissions venting through the borehole to below
explosive levels.
All workers were required to follow
the protocols laid out in a detailed Health and Safety Plan (HASP)
created for the project. The HASP included, among other things,
the following:
- Training requirements for the
workers, which included Self Contained Breathing Apparatus (SCBA)
training and first aid instruction
- The requirement to designate
a safety officer for the project.
- Details on safety equipment
to be worn and hazards that may encountered.
- Emergency response procedures
          
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the
drilling program continued
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