|
California Gulch CERCLA Site, OU6 – Lake County, CO (1998 - 2004)
As part of a project
that spanned seven years, project engineers of Frontier Environmental
Services, Inc. provided design support, work plans and project
specifications for the EPA removal Action at the California Gulch CERCLA Site
OU6. In the summer of 2004, construction involved the Ponsardine Mine waste
rock relocation and consolidation and the Robert Emmet crib wall and mine
structure rehabilitation project.
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 completed the
final phases of this project in the Fall of 2007. Approximately 35,000
cubic yards of materials were transported including 25,000 yd3
of waste rock and spoils.
 
London Mine Extension, Mosquito Gulch – Park County, CO (1997-2010)
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 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 spoils to the
repository. 2008 and 2009 included rehabilitation to collapsing mine
sections, thermal protection for pipes, and continued improvements to the
treatment system.
 
 
Golden Mile & Mayhem Gulch, Clear
Creek – Jefferson
County, CO (2008-2011)
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 (“J-hooks” and “cross-vanes”) with the purpose
of improving trout spawning habitats as well as protecting against stream
bank erosion. Phase 2 of the project involved installing more of these rock
structures further up stream. Frontier has since completed two similar
projects on Clear Creek. One (in 2010) in downtown Idaho Springs along
Riley Cooper Park, and the other (in 2011) in Mayhem Gulch. Both projects
used similar applications of boulder structures but Mayhem Gulch also
incorporated a stream bank stabilization known as “toe-wood” which utilizes
trees (with roots still attached) laid perpendicular to stream flow,
covered by vegetation and multiple layers of wrapped soil lifts.
 
Schwartzwalder
Mine – Golden, CO (2007-2010)
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 portals,
demobilizing all equipment in the site’s bone yard, decommissioning and
demobilizing all equipment from underground as well as many other duties.
Frontier returned in the fall of 2010 to install several sump stations as
well as underground utilities to help control and treat the contaminated
groundwater that flows between the mine workings and nearby Ralston Creek.
 
Pikes Peak
America’s Highway – Colorado Springs, CO (2007-2008)
In the Summer of 2007 and 2008, 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 was scheduled to take
place over several 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 a high rate of tourist
traffic through the jobsite. The project was an exciting new challenge for
Frontier.
California Gulch CERCLA Site, OU11 – Lake County, CO (2008-2009)
Beginning in the
Summer of 2008 and continuing through 2009, Frontier was retained by
Pacific Western Technologies and the EPA for work along an eleven mile
stretch of the Arkansas River southwest of Leadville, CO. The area along the river,
encompassing irrigated and dry land pastures as well as public and private
inholdings, is used for cattle ranching and recreational fishing; however,
over the past century acid mine drainage from mining districts upstream has
spread in to tributaries and irrigation ditches and settled out over the
valley base. The result was several hundred acres of land with sediments
high in heavy metals that could not support vegetation. Frontier’s task was
to remediate these soils in place by implementing 15,000 tons of lime and
48,000 cubic yards of compost both of which had to be transported in from
more than 100 miles away. The amendments were then distributed with
agricultural spreaders and heavy equipment at precise rates and incorporated
with specialized harrows and mixers at varying depths. Over 5 miles of
either electric or barbed-wire fencing was installed to keep livestock out
of the treatment areas. More than 3,000 linear feet of Arkansas River stream banks were stabilized
through various reinforcement means. To access areas along the riverbank
that was surrounded by wetlands, Frontier constructed more than 3 miles of raised
roads with geotextile and onsite screened rock as materials. These roads
along with all treatment areas were revegetated. Challenges of the project
included extremely cold temperatures, high winds affecting lime storage, flooding
from spring runoff and beaver dams, and the compatibility of mixing
equipment with desired analytical requirements. Frontier successfully
completed all aspects of this long and intense remediation project. Future
vegetation establishment and erosion protection throughout the treatment
areas will further reinforce the success of the project.
 
 
Grange Hall Creek Channel Improvements,
Phase II – Thornton, CO (2011)
During the spring and
summer of 2011, Frontier worked with the City of Thornton and the Urban Drainage and
Flood Control District (UDFCD) to relocate an existing sewer line that was
becoming exposed to Grange Hall Creek due to excessive erosion. Frontier
also improved several vertical-cut stream banks that were also caused by
the excessive erosion. Sewer project tasks included installation of
approximately 1500 LF of sewer pipe including two crossings (underneath the
creek) requiring steel casing, 6 manholes ranging in depth from 8 to 18
feet, and abandonment of 1200 LF of existing pipe. Rock had to be imported
to stabilize the quick-sand soils that were to form the pipe and manhole
foundations. Stream work involved the installation of 2100 LF of wrapped soil
lifts and 1600 LF of biologs that were built in-situ. The wrapped soil
lifts were constructed on slopes varying from 2:1 to 1:1 using soil-riprap and
geogrid reinforced coconut to shape the contours of the lifts. Willows,
seed and wetland plants were installed in between lifts to promote
revegetation. The koirmat biologs were hand rolled “burrito-style” and
incorporated willows, topsoil, wetland plugs, wetland seed, and straw.
 
 
CC&V Structure Relocation, Morning
Glory & Doctor Jackpot – Cripple Creek, CO (2012)
CHECK BACK FOR UPDATES TO THIS PAGE
|
|
