How To Have a Blast as a National Park Service Employee

New employees of any company or organization are faced with digging their way through various policy and procedure handbooks.  Typical tomes requiring shoveling include volumes on workplace health and safety, anti-discrimination policy, sexual harassment, and most recently the dos and don’ts of bullying.  These manuals are typically painful to read and require some sort of mandatory testing to artificially infuse interest.

NPS Handbook CoverOne employee handbook I recently came across, however, sparked my attention like no other.

National Park Service Handbook for the Storage, Transportation, and Use of Explosives

Now I have been fooled by YouTube™ videos where the advertised title and actual content were not in the least bit related.  I carefully kept my giddy expectations in check as I followed this link to the online book:

http://www.nps.gov/history/history/online_books/npsg/explosives/

It is quite possible that clicking this link blasts an automatic warning message at the Bureau of Tobacco and Firearms.  But even if it does, it also magically summons an eleven chapter, 221 page bible of wilderness pyrotechnics.

Many of us who have spent significant time in granite country have wondered in amazement at the trail excavation and armory work of various switchbacks and trail ledges.  We imagine the blood, sweat and tears exerted from the working end of a Pulaski, Mattock, or McLeod.

Blast HoleIn these areas of obvious labor, we occasionally stumble upon mysterious worm holes, the apparent effects of some giant silicon based life form.  Or is it?  Is it possible that in addition to exerting sweat, a subset of these NPS employees is actually having a blast?!

If the official job titles provided in the handbook are any indication, it seems there is no lack of people wanting at least a part of the action.  With no exaggeration positions include:

  • Park Service Blasting Officer
  • DSC Blasting Officer
  • Blasting Inspectors
  • Regional Blasting Officers
  • Chief Park Blasters
  • NPS Blasters
  • Explosive Handlers
  • Magazine Operator

I assume the latter is operating a device that holds explosive charges, as opposed to the latest issue of Field and Stream.

I confess to being a tad confused as to the target audience.  The same manual that explains the formula for calculating borehole depth when subdrilling:

(H = 2.5 x Ve x (B² + J²)½ + T) / Vr

Also explains:

Allow no one to handle explosives while under the influence of liquor, narcotics or prescription drugs that impair performance.

As a side note, I found no guidelines regarding performing the actual borehole calculations while under the influence.  Go figure.

Blastbore RemnantFor the backpacking layman, these procedures and people have something to do with removing big rocks by drilling holes in them and blasting them into new locations.  Pretty cool.

Most of us have seen remnants of these endeavors, without ever considering the science.  Let’s consider at least a portion of that burden.

In rock blasting, the term burden refers to the rock between the borehole and the open face or edge.  To successfully move it requires knowledge of the interrelations between the depth of the hole, the velocity of the explosive, and the velocity of the rock.

Blast Bench UpBy delaying charges in the boreholes, the total burden can be increased and direction controlled.  For example to move a large burden up off the bench, a series of rows can be timed in sequence.  The borehole row 1 is discharged, removing the burden from it to the face, freeing up the second discharge to take the burden from row 2 to 1, followed by row 3 to 2 and so on.

Edge Bench DiaganolSimilarly, if delaying in diagonal rows, the burden can be moved up and to the right.

So there really is a science to blowing up rocks.  So much so there are multiple levels of certification programs (NPS/65) for people who do this for a living.

All this requires basic physics and applied mathematics.  It occurred to me that if more teenaged boys were allowed to apply math in this explosive way, this next generation would be prepared to easily blow away our countries competition.  With burden removed, we would rock!

Leave a Reply