Projects
Laramide's staff has worked on environmental projects located throughout
the United States. Descriptions of representative project experiences
are provided below. Please contact Laramide
with any questions regarding our experience and capabilities to perform
specific projects.
Abandoned Lead/Zinc/Gold Mines, Colorado
Laramide was retained by the landowner to develop reclamation plans
for two abandoned mines near Breckenridge, Colorado. Historical mining
and milling activities had produced waste-rock and tailings piles that
impacted stream-water quality in neighboring streams.
Based on previous
data-collection and site-characterization results, we developed plans
for site reclamation to be implemented under Colorado’s
Voluntary Cleanup Program (VCUP). The plans included limited regrading
and covering of exposed tailings that contained metals above relevant
risk-based standards; development of wetlands to intercept adit discharges
and improve the quality of water entering the stream and alluvial aquifer
system; relocation of stream segments away from waste rock and tailings;
and institutional controls to limit access to the sites while maintaining
the historical character of the sites.
The plans were accepted by the
VCUP program. This acceptance was critical to completing transfer
of the property from the landowner to the county
government for inclusion in its open-space program. The reclamation
will be implemented by the county government after the property transfer
is finalized.
Abandoned Copper Mine, California
Waste rock from past mining operations had been disposed
of by dumping on a steep hillside adjacent to a stream. Water quality
in the stream was adversely affected by erosion from the waste rock
materials. We provided hydrologic and project-management support
to mitigate stream impacts and develop a waste-rock repository at
the site.
The waste-rock repository was located near the abandoned
mine. The chosen site was located well above the local groundwater
table to avoid potential problems with inundation of the waste rock
materials. The "high-and-dry" location also allowed the specification
of a less complex liner system.
The repository design included a cap and cover system to limit infiltration
into the waste rock in this area of relatively high annual precipitation.
The cover included the use of large cobbles and boulders to provide
erosion control as well as discouraging the operation of off-road
vehicles on the waste repository.
We worked closely with the project engineer in Denver, a local engineering
firm in California, and the state regulatory agency to ensure that
the design met all
local
construction
regulations. The design was submitted for implementation by the property
owner.
Chlorinated Solvent Remediation, New Jersey
We povided hydrogeologic evaluations to assist with the remediation
of trichloroethene (TCE) at an active manufacturing facility in
New
Jersey. TCE was found in groundwater over 20 years ago at concentrations
suggestive of residual free product in the fractured bedrock beneath
the facility. An established groundwater pump-and-treat system had
been ineffective in reducing concentrations or meeting remediation
goals.
We designed and supervised a combined soil-vapor extraction (SVE)
and air sparging (AS) pilot test at the facility. The objective
of
the pilot test was to determine if this aggressive approach could
significantly enhance mass removal from the subsurface. A helium
tracer
was used in addition to pneumatic pressure and flow measurements
to determine the effective remediation zone of the pilot system.
The
system was found to be effective and a full-scale SVE/AS system was
designed by the project engineer and implemented at the site.
Our staff also implemented a numerical model of groundwater flow
and contaminant transport at the site to evaluate suitable remedial
action
goals for the facility. The model was used to demonstrate that natural
attenuation would control off-site transport at a residual TCE concentration
much higher than the default state standard. Results of the modeling
also indicated that an off-site source was likely responsible for
a portion of the on-site groundwater contamination. The model results
were used to support a higher, site-specific remedial action goal
for groundwater concentrations that was eventually accepted by the
state regulatory agency.
Groundwater Flow and Contaminant Transport Modeling, California
Laramide provided numerical modeling and technical support to evaluate
the potential historical impacts of groundwater contamination on
municipal
water-supply and irrigation wells. The work was performed to assist
the designated expert witness in his evaluation of historical conditions
pursuant to litigation. MODFLOW and MT3D were used in the GMS modeling
environment to complete the project.
An existing regional groundwater flow model was used as the basis
for the modeling effort. The groundwater flow model was re-calibrated
to improve its predictive power in the main area of interest. A contaminant-transport
model was developed based on the physical system represented by the
flow model and further calibration was performed using both water-level
data and an extensive database of contaminant concentrations.
Results of the flow and transport modeling were used in conjunction
with measured data to predict wellhead concentrations at a number
of wells of interest in the potentially affected area. We collaborated
with the designated expert to develop a post-processing spreadsheet
that incorporated information about the physical layout of the wells
along with the data and model results to estimate the most likely
wellhead concentrations. The results of the evaluation were presented
by the designated expert in extensive deposition testimony.
Technical Review of RI/FS and EE/CA Documents, Illinois
Laramide and a team of risk-assessment experts are providing
technical review of RI/FS and EE/CA documents under contract to the
United States Army Corps of Engineers on behalf of the USEPA.
The site includes several unlined landfills containing a variety of
chemical wastes. An estimated 1 million cubic yards of waste materials
are included in the landfill areas, with the bases of most of the landfills
beneath the water table. Discharges from the landfills have severely
degraded groundwater quality with a variety of organic and inorganic
contaminants, threatening a nearby stream, lake, and the Mississippi
River.
Laramide has provided technical comments on the results of groundwater
investigations and on proposed remediation activities. Along with
its subcontracted experts in risk assessment, Laramide has reviewed
and commented on baseline and residual ecological risk assessments
performed by the Potentially Responsible Parties (PRPs) for the site.
We have participated in several conference calls and meetings with
the PRPs to
help streamline the project planning and review process and improve
the quality of future data collection efforts.
Ongoing project phases include assessment of source-area DNAPL contamination
and finalization of sediment and impacted-soil removal
from a creek bed at the site. We continue to work with the USEPA,
the Illinois Environmental Protection Agency, and the PRP group to
help
ensure the soundness of the technical approach while satisfying federal
and state environmental regulations.
Additional Examples of Past Project Activities:
- Evaluation of groundwater and surface-water contamination
due to tailings piles at an operating copper mine in Arizona.
- Assessment and mitigation of nitrate contamination
in groundwater due to waste-rock disposal at an operating gold
mine in South Dakota.
- Evaluation of groundwater contamination due to unlined
evaporation ponds, optimization of groundwater monitoring network
in Wyoming.
- Technical review on behalf of landowner of Engineering
Evaluation/Cost Analysis documents prepared by state regulatory
agencies for abandoned mine sites in Colorado.
- Project management for post-remediation groundwater
monitoring at a Superfund site in Wyoming.
- Groundwater flow and transport modeling to evaluate
potential historical impacts of perchlorate and NDMA contamination
on a public water-supply well in California.
- Groundwater flow modeling to evaluate regional impacts
of coal-bed methane development on water resources in Wyoming
and Montana.
- Feasibility study of innovative in-situ remedial technologies
for chlorinated solvents in groundwater to accelerate cleanup
at an active manufacturing facility in Washington.
- Environmental permitting for acquisitions of existing
manufacturing facilities by client company at sites across the
United States.
- Conceptual design of soil-vapor and groundwater extraction
systems under Superfund. Optimized designs resulted in substantial
capital and operational cost savings at sites in Wisconsin,
Indiana, and Ohio.
- Remedial investigations and feasibility studies under
Superfund and state regulations.
|
