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California Gulch CERCLA Site, OU6 – Lake
County, CO (2004)
Project engineers of
Frontier Environmental Services, Inc. provided design and engineering
support, design drawing development, work plans and project specifications
for the EPA removal Action at the California Gulch CERCLA Site OU6:
Lake County, Colorado, for the Ponsardine Mine waste rock relocation and
consolidation and the Robert Emmet crib wall and mine structure
rehabilitation project summer 2004.
Frontier’s project engineer designed a precast concrete retaining wall
system as well as a drainage system behind the wall to alleviate
hydro-static pressure. Clean imported fill was added to help support the
structure.
 
Pride of the West Mine, Cunningham Gulch –
San Juan County, CO (2005)
Frontier
Environmental was retained by the State of Colorado Division of Minerals
and Geology for remediation services at the Pride of the West Mine, a
remote site accessed only by foot or helicopter. All tools and equipment
were flown in to the site. The purpose of the project was to seal off water
infiltration through the stope and reduce or eliminate heavy metals loading
to the Animas River Watershed. The project involved a three step process
which entailed drilling the rock surfaces to accommodate the steel beams
that would span the 40 foot width of the stope. Installation of the 49
W12X65 steel beams and ¼” custom cut steel plate was done with a KMAX
helicopter and fastened to the cliff walls with 1” Williams bolts and
concrete. The final stage of the project included welding the steel,
spraying on anti-corrosion protection, and sealing the edges of the stope
with grout. Over 243,000 pounds of steel was used to fabricate this cover.
Frontier personnel worked four months to successfully complete this
project.
 
 
Gateway - Davis Mill Remediation Project – Mesa County, CO (2006)
Frontier
Environmental was retained by the Colorado Department of Public Health and
Environment for the systematic cleanup and disposal of Uranium mill
tailings at the Davis Mill site and adjacent CDOT facility in Gateway,
Colorado. Frontier relocated large amounts of debris in order to have
access to areas of concern. Contaminated soil on the property was carefully
excavated with heavy equipment, stockpiled, and loaded onto trucks for
transport to the Umetco Repository located 38 miles away in Uravan Colorado. Frontier initiated the
implementation of the work plan with the excavation and disposal of more
than ~26,000 CY of contaminated soils between the two sites. NaI
scintillometers were used to screen areas of contamination on the site. The
project included post cleanup verification surveys, calculation and
presentation of post cleanup site risks that still remain. Frontier
regraded the site to near pre-construction grades and re-installed fences
and corrals for livestock and property boundaries.
Joe & John/Lark Mine, Prospect Gulch –
San Juan County, CO (2006-2007)
Frontier
is currently retained by the State of Colorado Division of Reclamation,
Mining, and Safety (DRMS) for abandoned mine reclamation services at the
Joe and John / Lark mines and associated dumps located in Prospect Gulch in
San Juan County, Silverton, Colorado. Frontier
constructed a PVC lined 100’ x 100’ x 22’ deep earthen repository with
under drain system for the storage of mine waste rock / spoils derived from
the Joe and John waste pile and the Lark dump. Frontier used conventional
earth moving equipment to relocate portions of the Lark dump in order to
construct a large repository on the side of the mountain. An existing abandoned
mine access road to the upper Joe and John waste pile was improved to gain
access to the pile for the load out with heavy equipment. Accessible
material was trammed down the mountain and stockpiled at the Lark dump for
future placement into the repository located near the Lark dump. Due to
inclement weather in the Fall of 2006 (heavy rains and snow), Frontier had
to suspend the project for the winter. Frontier is planning on resuming the
final phases of this project in the Spring of 2007.
 
London Mine Extension, Mosquito Gulch – Park County, CO (2006-2008)
The
London Extension Mine located in Park County, Colorado is an abandoned
gold and silver mine drain tunnel owned by a private client who is
responsible for the treatment of the AMD effluent emanating from the
underground workings. Frontier has provided ongoing operations and
maintenance on this mine site since 1997, and in the fall of 2006, Frontier
provided new treatment upgrades including: new in-line pH and flow meters,
two new electric actuated control valves, a new treatment tank, a SCADA
monitoring system, misc. piping and valves associated with drain and
conveyance systems, coffer dam installation, sediment pond improvements and
new repository construction. Frontier’s efforts required surface and
underground work with conventional heavy equipment and trained underground
workers. 2007 saw continuing improvements to the surrounding sediment ponds
and transport of contaminated pond sludge and soils to the repository. 2008
will see rehabilitation to collapsing mine sections and continued
improvements to the treatment system.
 
 
Golden Mile, Clear Creek – Jefferson County, CO (2008)
The
Golden Mile is a project located in and around Golden, CO along Clear Creek
directed toward improving fish habitat and providing a better width to
depth ratio of the stream. Frontier was retained by the West Denver Chapter
of Trout Unlimited for the design and implementation of the project
drawings. In Phase 1 of the project, Frontier used heavy equipment to
install five rock structures with the purpose of improving trout spawning
habitats as well as protecting against stream bank erosion. Phase 2 of the
project will involve installing more of these rock structures further up
stream and will be carried out in late 2008 or early 2009.
 
Trout Creek Pond Rehab – Park County, CO (2006-2008)
Another project that Frontier’s design team has worked
on for Fall 2006 and Spring 2007 is the Trout Creek Pond Rehabilitation
Project located south of Fairplay, CO in Park County. Past pond
modifications have left the pond shallower than historic high stages. A
re-design and re-construction of the outfall from the dam to raise the
water level is being engineered along with sediment catches and drop pools
(fish ladders) for fish migration. Three islands were constructed in the
pond area to not only provide more nesting habitat but also protect against
predation of the waterfowl.
 
Schwartzwalder
Mine – Golden, CO (2007-2008)
Beginning in the summer of 2007, Frontier was retained
by Cotter Corporation to decommission their site at the Schwartzwalder Mine
located northwest of Golden, CO. The mine was the highest producer of
Uranium ore in the state for several decades. Frontier accomplished several
tasks including installation of safety closures to several mine adits,
demobilizing all equipment in the site’s bone yard, decommissioning and
demobilizing all equipment from underground as well as many other duties.
Pikes Peak America’s
Highway – Colorado Springs, CO (2007-2013)
In the Spring of 2007, Frontier worked with Pikes Peak America’s
Highway (PPAH) to re-grade and re-pave the Pikes Peak Highway from 12,000ft
to the summit at 14,530ft. The project is scheduled to take place over the
next 6 years. The first phase of the project was located near “Devils
Playground” at 13,000ft. The area was named for its propensity to be struck
by lighting. The project consisted of constructing an elaborate storm water
drainage system which included: concrete-reinforced ditches, rip/rap-lined
sediment traps with weir overflows, concrete culvert inlets, rip/rap-lined
culvert outlets, re-grading of the
highway with the addition of Class II road base, and paving the highway.
Drainage ditches were lined with dyed concrete to simulate natural
surroundings and reduce erosion during spring runoff and heavy storms.
Challenges of the project were extreme weather and high tourist traffic
through the jobsite. The project was an exciting new challenge for Frontier,
we look forward to another work season on “America’s Mountain” in Spring
2008.
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