Monthly Archives: July 2018

Silica Exposure Control Programs in the Drilling Industry

Silica Exposure Control Programs in the Drilling Industry

We are all gaining familiarity with “Table 1. SPECIFIED EXPOSURE CONTROL METHODS WHEN WORKING WITH MATERIALS CONTAINING CRYSTALLINE SILICA” of OSHA’s Crystalline Silica Rule for Construction –  a title that kind of rolls right off the tongue.  Table 1 was OSHA’s attempt to guide contractors in reducing silica exposure below the new permissible exposure limit (PEL) of 50 ug/m3.  For most of the construction industry, it largely works and boils down to two things – use water or use a vacuum.  Common tasks such as cutting, chipping, drilling and grinding concrete are listed in Table 1 along with the precautions the contractor must do to stay below the PEL.  Do these tasks with these precautions and you’re all set.  But what happens when your task is not listed?  This is the place that the drilling industry finds itself.

The tie-back and micropile industry drills rock on a regular basis.  According to Encyclopedia Britannica, “The mass of Earth’s crust is 59 percent silica, the main constituent of more than 95 percent of the known rocks.”  OSHA requires that exposure to safety or health hazards be eliminated through administrative or engineering controls if possible.  Our industry most commonly drills rock with down the hole hammers.  These hammers are single pistons at the bottom of the drill rods that actuate a bit up and down through the power of high pressure, high volume air compressors.  The primary engineering control is to drill with water.  The volume and pressure of the water must be sufficient to reduce silica exposure below the PEL.  So how do we know that we are protecting our workers during drilling?  We test.

The OSHA rule for silica exposure has two options for assessing employee exposure when not following Table 1 – the Performance Option and the Scheduled Monitoring Option.  The Performance Option requires assessing employee exposure based on any combination of testing and objective (read industry) data.  Unfortunately, we don’t have industry data, but we’re working on it.  More from ADSC on this in the future.  At Subsurface Construction are focusing on the Scheduled Monitoring Option for drilling.  Scheduled Monitoring means testing for respirable silica on individual employees while drilling with engineering controls in place.  Depending on the results, OSHA guides the employer as to what additional testing is required.  Unfortunately, monitoring is not a one-time event as the rock formations and drilling conditions can vary site to site.  To date, we have not been over the PEL when drilling rock with water, but we will continue to wear respirators as we gather more data.

Recommended reading: https://www.osha.gov/Publications/OSHA3902.pdf
Recommended action: Join an upcoming Silica Competent Person class through ABC, AGC or local safety training partners.

Leadership Development

Recently our Regional Managers, Alex Smith, PE and Jodie Nixon, PE, attended the Bell Leadership Institute’s Achievers™ conference in Raleigh, NC.  The Bell Leadership Institute is a leading organization in executive education and development helping organizations through its programs and services since 1972.  The focus of the Achievers™ conference is “become a great leader by building yourself first”.  The three-day training conference is designed to help you lead like the best in the world with a deep understanding of your personal strengths, weaknesses and motivations.

The training program is based on a half century of research and consulting with thousands of leaders across the world.  Achievers™ is unlike other programs in that it goes deeper, providing key understandings of why you behave as you do. Knowing yourself deeply and how your behaviors affect others enables you to develop your unique leadership style.  With Bell’s model, personal assessments and those from invited colleagues, attendees are provided with a deep understanding of their behaviors, thought patterns and then a plan for developing into a well-balanced leader.

“I am glad that I invested the time to go through the Achievers™ training program.  I was encouraged by receiving a better understanding of my strengths and challenged to make improvements with a better understanding of my weaknesses.  My eyes were opened and I now have a better understanding of why I think and behave certain ways.  With knowledge, the path of improvement is much easier to follow.  I would encourage other companies to invest in their team members with Bell’s Achievers™ program.” – Jodie Nixon, PE

To learn more about this program visit https://www.bellleadership.com/seminars/achievers/

Virginia War Memorial Shoring Support

VA War Memorial featured in Foundation Drilling Magazine

Subsurface Construction is honored to have the Virginia War Memorial as a Technical Featured article in Foundation Drilling Magazine July 2018, a publication of the Association of Drilled Shaft Contractors (ADSC). Subsurface designed and constructed a permanent anchored secant pile wall and a temporary soil nail wall for the expansion project.

For the secant pile wall, Subsurface teamed up with the experts at Equipment Corporation of America (ECA) to supplement its own experience with this construction method. From the initial bidding process to the wall’s construction, Subsurface worked closely with ECA’s Gordian Ulrich and Jeff Harmston to assess the appropriate drill rig and tooling needs. Casing was required due to the soft ground, presence of groundwater, and accuracy of the alignment of the piles. Subsurface used a Bauer BG 20 rig with 35-inch sectional casing and an earth auger for secant pile installation. The process alternated between 1-2 days of primary pile construction and 1-2 days of secondary pile construction spaced at 6 ft. on center. The construction of the secant pile wall as a success and was completed two weeks ahead of schedule.

For the temporary shoring, Subsurface designed and installed a hybrid pipe pile and conventional shotcrete soil nail wall had an overall retained height of approximately 35 ft. A primary challenge with design and installation was coordinating the location of soil nails (+/-45 ft. long) to miss existing utilities and soil nails on the opposing side of an outside corner. Subsurface was concerned that despite engineering the nails to miss, slight drilling deviations would inevitably cause damage to previously installed nails. To mitigate this risk, significant effort was spent on the layout of each
soil nail while continuously monitoring during drilling to ensure the original alignment was maintained. In addition, the shotcrete facing was not applied until all drilling within the zone of opposing nails was complete for each lift.

To learn more about the installation, project challenges and modeling/measuring of deflections please read more:

Foundation Drilling Magazine