On its own, a horizontal directional drill (HDD) shot spanning more than 1,500 ft (457 m – the length of the average Par 5 golf hole), while long, can be relatively straightforward. That is until volcanic and clay ground conditions are added in, a tight deadline is required and on an environmentally protected jobsite.
This was the mission Jerry’s Trenching Service was tasked with in Clear Lake,
California, USA. The underground construction company, with a history dating back
to 1964, was called to the site to move an existing AT&T intercontinental fibre line in
order for a bridge expansion to take place.
“When my father founded Jerry’s Trenching, he focused on efficient and creative
solutions to problems.” said Jerry Berlin Jr, CEO of Jerry’s Trenching Service. “When I
think about jobs that test those values, the Clear Lake job is the right at the top of the
list. We encountered a variety of issues and we needed to trust our technology and
our crew.”
A Long List of Challenges Requires the Right Equipment
When the crew, led by Jose J. Sandoval, arrived on-site in Clear Lake, they quickly
realised the challenges they were facing for the job. To start, they would be drilling under an environmental reserve, eliminating the possibility of excavation or potholing to provide visibility or relief. The good news was that there were not any existing lines in the area outside of the original line that the crew was splicing over to, and they were allowed to trench in the last 15 ft (4.5 m) of the job to make sure the tedious splicing process was safe. That said, the reserve also happened to be full of poison oak, forcing the crew to wear personal protective equipment from head-to-toe to protect themselves.
The ground conditions added further difficulty. While HDD jobs of this length are
commonly through dirt (soil), this job was through hard volcanic rock, with scattered
pockets of clay along the route. The rock would test the horsepower limitations of
any machine, but the clay pockets complicated matters further.
Each time the crew found clay, they needed to completely pull out of their established hole, clean the hole and then mix new drilling mud to drill through the new conditions. Then they would need to retool and repeat for the hard rock once they returned to those ground conditions.
Lastly, the clock was ticking. The team had an extremely tight deadline they needed to meet in order to accommodate scheduled downtime for the existing intercontinental fibre line, which was responsible for transferring vital information to companies throughout the United States. The downtime had been planned months earlier and missing the mark would be extremely costly financially and operationally to the businesses that depended on that fibre line. “The jobsite was a challenge.” Berlin said. “We knew it was a long drill shot going in, but as we got to work and found out about the other factors, we knew it would be difficult. Once we fully realised the challenges of the conditions, we got on the phone with Ditch Witch.”
Counting Down to an All-Terrain Solution
Jerry’s Trenching Service turned to the Ditch Witch AT40 Directional Drill for the project. Designed for increased control and productivity when drilling in hard rock conditions, All Terrain technology would limit the impact of the ground conditions on the job.
“We have always used AT30s, but we really wanted the AT40 for this job because
the larger 15 ft (4.5 m) bore rods would help us on the longer shots.” Berlin said. “Also, the AT40 has an inner pipe that we could get air through, so we could run an air hammer with it. We knew the AT40 would help us out. It got to the point where we were counting days and shipping hours until the AT40 would arrive.”
The arrival of the AT40 and its All-Terrain technology opened up the opportunity to use much less drilling fluid than is needed with typical mud motors. The compact size of the AT40 also minimised the overall footprint of the job, an important benefit due to the environmentally sensitive nature of the jobsite.
With the use of All Terrain technology and the crew’s expertise, they hit their mark in just over three weeks. The 1,540 ft (470 m) bore was a new record for Jerry’s Trenching Service, beating out the previous mark by over 300 ft (91 m), a mark that had been set two decades ago in dirt, not volcanic rock.
Jerry’s Trenching Service Hits the Road
The knowledge and experience that comes with using All Terrain technology on complicated rock drilling jobs is now an asset for Jerry’s Trenching Service. Furthermore, since many cities do not have an abundance of rock jobsites, Jerry’s team decided to take their skills on the road by forming a travelling rock drilling team to support jobs across the region.
“We have always had All Terrain technology on site for when we were faced with rock, but now we have seen how it can help on difficult, unpredictable rock drilling jobs.” Berlin said. “We also now have an experienced, energetic crew that wants to travel. Now we can find and conquer any rock drilling job.”
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