Title : Blasting for fill rock, McMurdo<
Type : Antarctic EAM
NSF Org: OD / OPP
Date : June 1, 1993
File : opp93008
DIVISION OF POLAR PROGRAMS
OFFICE OF SAFETY, ENVIRONMENT AND HEALTH
202/357-7766
MEMORANDUM
Date: October 2, 1990
From: Environmental Officer, DPP
Subject: Environmental Action Memorandum (Blasting for, and
Placement of, Fill Rock at McMurdo Station,
Antarctica During the 1990-1991 Season)
To: File S.7 (Environment)
The U.S. Antarctic Program (USAP) has developed a policy, and
implementing procedures, to minimize the potential environmental
and aesthetic impacts associated with gathering of local fill.
The policy recognizes that the collection and use of local
antarctic fill materials for use in construction and other
purposes poses potential environmental and aesthetic impacts and
is controversial. Nonetheless, the USAP recognizes that there is
a genuine need for such material in construction and other
purposes and believes that the collection and use of this natural
resource can be managed with the goal of minimizing such impacts.
The policy's goal is being achieved through: 1) a system for
considering, authorizing and reporting all instances of fill
gathering (including such activities as use of explosives to
facilitate fill gathering, and grading); 2) evaluation and
utilization of other materials, approaches or technologies that
lead to minimization of fill gathering; and, 3) collection and
maintenance of information on collection of fill and associated
activities at McMurdo Station.
This Environmental Action Memorandum (EAM) is intended to
document how the various requirements of the policy are being met
in light of needs for fill materials at McMurdo Station during
the 1990-1991 season.
Authorizations are now required for blasting and fill gathering
activities not already addressed in a project-specific
environmental impact assessment or in the U.S. Antarctic
Program's Programmatic Environmental Impact Statement: These
include obtaining rock fill for:
o Construction of McMurdo Station's submerged domestic sewage
outfall quay;
o Maintenance to counter erosion of McMurdo Station's potable
water intake quay; and
o Finalizing grading at McMurdo Station's new Science Facility.
Also, documentation is required for gathering and placement of
fill for such non-project-specific activities that occur on an
annual basis at McMurdo Station as:
o Provision of fill for utility road crossings; and
o Provision of fill for road maintenance.
USAP's civilian contractor was tasked with answering the
following questions to aid decisionmaking on the potential
significance of environmental and aesthetic impacts associated
with gathering (i.e., blasting) and placement of fill materials:
Question 1: Which areas will be affected (include areas of
removal or placement, and where blasting and grading will occur)?
Response 1: The areas to be blasted are included in McMurdo
Station's Blast Site No. 2 (shown on Map 1). Specific areas
where fill will be placed include: 1) the sewage outfall quay;
2) the potable water intake quay; and the site of the new Science
Facility. General areas of fill placement will be at utility
road crossings and on road surfaces.
Question 2: What is the nature of disturbance that the areas
have experienced in the past?
Response 2: The areas to be blasted have been scraped in past
years for gathering of fill. The areas near the sewage outfall
and water intake quays both have been disturbed by placement of
rock and fines fill during construction of the quays; also, the
marine environment near the outfall quay receives inputs of
sewage-related nutrients and sediments (the environmental impacts
of these inputs as well as of actions to mitigate the impacts
were assessed previously). The area around the new Science
Facility is a site of continuing construction; and, the impacts
of this project have been assessed previously. Finally, fill
is placed annually at utility road crossings and on road surfaces
around McMurdo Station.
Question 3: What indications are there that antarctic wildlife
may inhabit the affected sites?
Response 3: Antarctic wildlife do not normally inhabit or
traverse the site of the proposed blasting which has been
previously scraped; and, such wildlife are not found at
terrestrial sites of fill placement. Antarctic marine biota
(i.e., primarily, phyto- and zoo-plankton, benthic and pelagic
organisms) are present, however, in McMurdo's nearshore waters--
and at the sites of fill placement for quay construction and
maintenance. Potential impacts to these organisms was assessed
in the environmental impact assessment on wastewater noted above.
Question 4: What alternatives to the collection and placement of
local fill have been considered?
Response 4: The civilian contractor has considered importation
of fill materials. Import of such materials was found to be
prohibitively costly and logistically infeasible. An old rock
fill quarry located at Observation Hill was noted to contain good
rock; but, this area was not chosen due to potential
environmental and safety risks. Blast Site No. 1 (see Map 1)
contains suitable fill material; however, its proximity to fuel
lines poses safety risks. Areas at Arrival Heights, near the
station, were explored but suitable rock material was not found.
An area near the termination of the Pram Point fuel line
contained suitable rock; collection of that material would
require coordination with the New Zealand Antarctic Research
Program's Scott Base and would require moving collected material
greater distances than from the Blast Site No. 2 area.
Question 5: How much fill material would have to be collected?
What will this fill material be used for specifically?
Response 5: Approximately 4,000 cubic yards. That is, ~2,500
yards3 at the outfall quay and ~500 yards3 at the intake quay;
~100 yards3 to fill gabions at the outfall quay; and, ~900 yards3
for such miscellaneous, annual projects as fill for utility road
crossings and road maintenance, and for final grading at the new
Science Facility.
Question 6: Describe the work plan for blasting operations.
Response 6: Three explosive shots will be accomplished to
establish a working face on the parent material. Each shot will
cover an area 80' x 6' deep (~142 yards3) using 106 pounds of ICI
AN95-65mm explosive, 250 feet of detcord, 9 surface delays, and
one electric cap. An area will be excavated from Blast Site No.
2, back toward Blast Site No. 1.
On the working face, six shots each of area 80' x 24' x 8' will
be made, using 425 pounds of AN95-65mm explosive, 3,600 feet of
detcord, 250 surface delays, and 6 electrical caps. Holes will
be 8 feet deep with 8 foot spacing and 6 feet of burden.
Upon completion of quarry operations, approximately six shots
(similar to those for establishing the working face) will be
required to remove the face, slope the area, and reduce future
hazards to pedestrian and equipment traffic. Then the site will
be graded (re-landscaped) to its original aspect to blend with
the surrounding area. No waste materials will be left at the
site.
FINDING: There is no question that operations required for the
collection (i.e., blasting of bare rock surfaces) and placement
of fill will engender genuine environmental and aesthetic impacts
to the chosen area; however, the blasting and collection are not
new uses of that land parcel, and do not change the traditional
use of the site. Blasting and removal of rock from the location
does not pose a risk to any significant assemblages of antarctic
wildlife. Such wildlife as rock surface-inhabiting mosses and
lichens do not exist at the site. Collection of this fill
material will help to continue operational and maintenance
aspects of the U.S. Antarctic Program without posing a
significant or undue impact to the antarctic environment. The
policy and procedures now established for the consideration,
justification and documentation of fill gathering activities will
help USAP to minimize the need for, and potential impacts of,
these activities.
The Operations Research Analyst, DPP, shall compile pertinent
information on this activity in a "local fill collection
database" to inform future authorizations and decisionmaking as
instructed by Safety, Environment and Health Program Policy
Memorandum 90-2 (October 1, 1990).
Approval is granted for collection of fill materials, according
to the plans outlined by the civilian contractor (and as digested
in this Environmental Action Memorandum).
Sidney Draggan
cc: Safety, Environment and Health Officer, DPP
Acting Manager, Polar Operations Section, DPP
Facilities Engineering Projects Manager, DPP
Head, Safety, Environment and Health
Implementation Team, DPP
Environmental Engineer, DPP
Operations Research Analyst, DPP