Sulfur Mine Remediation, Construction and Closure

Sulfur Mine Remediation, Construction, and Closure, Oakland, CA

Insight performed remedial closure and creek restoration activities at a sulfur mine to 1) isolate mine tailings, 2) reduce acid mine drainage (AMD), and 3) restore a creek.  Insight was the environmental construction contractor.

Mine Tailings Isolation/AMD Reduction – Insight increased slope stability to prevent further erosion of mine tailings, encapsulated mine tailings to mitigate AMD, removed tailings deposits from a creek channel, consolidated all tailings beneath a 60-mil geomembrane cap and placed 12-inches of topsoil that was hydroseeded with vegetative cover.

Creek Restoration – Insight restored a creek channel to accommodate a 100-year flood event, constructed drop structures (steps, step pools, and cascade features) within the restored channel, reinforced soil slopes (RSS) along the restored channel, installed subsurface drainage systems beneath the cover and behind the RSS to route subsurface flows into the channel, and diverted storm water runoff into the creek channel.

Insight performed the following tasks:

  • Erosion and Sediment Control – implemented stormwater BMPs – straw waddles, silt fencing, and geotextile fabrics.
  • Temporary Diversion of Creek – performed excavation of a spring, and performed temporary diversion of Leona Creek during construction.
  • Mine Adit Closure – controlled seep drain, excavated and closed air shafts and mine adits by backfilling with large boulders and compactable material.
  • Mine Tailings Isolation – Excavated and stockpiled over 10,000 CY of mine tailings, replaced and compacted the tailings in 1-foot lifts, installed subsurface drainage, and installed 1.9 acres of geomembrane.
  • Reinforced Slope Stabilization – Installed a HDPE geogrid in 1-foot lifts to stabilize final slopes of 1:1 and 1:2 (H:V).
  • Creek Channel Restoration – Excavated mine tailings from the creek channel, installed channel filter fabric and constructed drop/cascade structures, and imported and placed 2,000 tons of boulders and riprap in the creek bed to manage a 100-year flood event.
  • Site Restoration – Imported, placed, and compacted 4, 000 tons of soil vegetative cover layer, hydro-seeded the cover with native grasses and repaved 4,900 SF of asphalt roadway.

Contract Value $1.4 Million

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Remedial Action for Five Burn Ash Sites

Remedial Action for Five Burn Ash Sites, Two UST Sites, and Pesticide Impacted Soil, MCB Camp Pendleton, CA

Insight removed and disposed 170,500 tons of CERCLA regulated metals-contaminated soil from five burn ash IR sites, characterized and segregated/wastes, collected confirmation samples, backfilled with clean soil, and re-vegetated the sites.  We handled and loaded wastes into trucks or rail cars and coordinated off-site disposal of 7,000+ loads.  When unexpected buried drums were encountered, we removed and treated contaminated soil and groundwater from the leaking drums.  As part of Navy-initiated options and modifications at other base locations, we conducted several emergency removal actions at several underground storage tank (UST) sites, and removed soil at an agricultural field under a fast-track schedule.

Work features that Insight performed on this project included:

  • Prepared a Site Management Plan, SAP, H&S Plan, EPP, SWPPP, waste management plan, and transportation/ traffic control plan.
  • Used excavators, front-end loaders, and dump trucks to excavate soil to a maximum depth of 19 feet bgs at 5 burn ash disposal sites.
  • In order to reduce fuel emissions, we used rail cars rather than trucks to transport excavated soil at certain sites.  We also used biodiesel in selected heavy equipment to reduce air emissions.  NAVFAC Southwest and MCB Camp Pendleton received the Clean Air Award for this project from US EPA at a ceremony held at the MCB.
  • Treated over 380,000 gallons of extracted groundwater onsite using GAC and ion exchange, allowing for discharge to the wastewater treatment system instead of costly off-base disposal, resulting in $300K cost savings.
  • Developed and then implemented a biological avoidance and mitigation plan to protect federally endangered species (light-footed clapper rail, arroyo toad).
  • Provided an archaeologist to ensure areas of historical significance at IR Site 30 were not affected.
  • Re-vegetated sites with native plant species to re-establish critical habitat that was temporarily impacted during construction.
  • Constructed and maintained temporary roads, security fences, temporary utilities, trailer, and decontamination areas, as well as rerouted a 10-inch water line.

Contract Value $33.1 Million

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Contaminated Sediment Removal

Contaminated Sediment Removal, Omega Aircraft Crash Site at Naval Base Ventura County, Point Mugu, CA

Insight performed wetlands sediment sampling, contaminated sediment removal, and wetlands restoration at the site of a Boeing 707 refueling aircraft crash and debris field in a wetlands area near the end of a runway at Naval Base Ventura County, Point Mugu, CA.

  • Characterizing Impacts to Wetlands Sediment/Soil and Surface Water – Insight collected samples at the crash site and associated debris field, evaluated sediment sample data, and evaluated remedial alternatives.  Insight performed activities to minimize additional impacts to wetlands vegetation and wildlife, coordinated extensively with multiple military and other agencies for this sensitive emergency response project, and coordinated the tight schedule due to its active airfield location and presence on a military base.
  • Contaminants:  Jet fuel (JP-8) and associated fuel VOCs including BTEX and semi volatile organic compounds (naphthalene, etc.), TPH-extractable, and metals (especially antimony, arsenic, cadmium, lead, molybdenum, vanadium), fuel and oils (TPH-motor oil, TPH-diesel, TPH-kerosene range)
  • Removal Action – Insight excavated 2,035 cubic yards (CY) of contaminated sediment (1,965 tons) over 34,000 square-foot area.  Confirmation sediment sampling and over-excavation of additional sediment was performed as needed to achieve cleanup goals, backfilled the excavation area with suitable sediment, and transported and disposed waste at an off-site disposal facility.
  • Work features performed included:
    • Planning Documents – Work Plan, Site Safety and Health Plan, Sampling and Analysis Plan that included a QA Plan, Accident Prevention Plan
    • Contaminated Sediment Characterization – 27 samples
    • Contaminated Sediment Removal – 2,035 CY
    • Confirmation Sampling – 21 samples
    • Waste Disposal – 80 truckloads
    • Backfilling and Site Restoration – 2,070 CY
    • Licensed land surveying
    • Coordinated laboratory analysis

Contract Value $0.70 Million

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Demolition and Waste Abatement

Demolition and Waste Abatement of Desert Vista Housing Complex, Mountain Home AFB, ID

Insight performed demolition for 184 housing units, 199 foundations including all utilities, site vegetation, associated site features, playground areas, asbestos abatement, abatement of universal waste and hazardous materials, demolition, excavation and disposal of pesticide contaminated soils, landscape design and green-space construction of the 42-acre former Desert Vista Housing complex, Mountain Home Air Force Base (MHAFB), Idaho.

  • Prepared Demolition, Landscape and Management Plans
  • Asbestos Survey – identified housing units with ACM such as roof shingles and floor tiles, and other universal waste (e.g. mercury switches, fluorescent lights, light ballasts)
  • Landscape Preservation – identified trees for preservation, installed high visibility fencing, and performed tree preservation measures.
  • Landscape Demolition – removed 674 trees, weeds, rocks, invasive plants, and undesirable shrubs.
  • Above Ground Utilities Demolition – removed all overhead utilities and associated components, utility poles and light posts, and transformers.
  • Demolition of Housing Units – abated, removed, and disposed of all hazardous materials from housing units based on Asbestos Survey Report.  Demolished and removed all housing unit superstructures.  Removed all demolition waste and debris from site.
  • Demolition of foundations – removed and disposed of all pesticide contaminated soil, then demolish and removed all concrete foundations and underground utilities and re-established an 8-inch water main across the site.
  • Demolition of asphalt roads, concrete curbs and gutters
  • Demolition of playgrounds
  • Removal of appliances including stoves, dish washers, refrigerators, water heaters, heating & air conditioning units.
  • Salvaged, reused and recycled building materials and appliances.
  • Installed and maintained landscaping and irrigation for 2 years

Contract Value $3.8 Million

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Performance-Based In Situ Groundwater Bioremediation

Performance-Based In Situ Groundwater Bioremediation of TCE and Excavation of PCB Impacted Soil, Sites SS014 and SS015, Scott AFB, IL

In-Situ Groundwater Remediation – Enhanced Bioremediation (SS-14)

To remediate chlorinated solvent contaminated groundwater in three distinct hot spots, we designed, installed, and operated an in-situ groundwater remediation system that involved injecting EOS® substrate, bacterial culture, and amendments to promote bio-augmentation and bio-stimulation.  We also injected sodium bicarbonate buffer solution to maintain pH conditions conducive to microorganism growth.  The system included an initial injection as well as a second injection 18 months later to enhance bio-stimulation.  Insight performed pre and post-injection performance sampling by monitoring groundwater at 39 wells.  We performed the following:

  • Prepared Remedial Action Work Plan, QAPP, SSHP, Waste Management Plan, and CQC Plan
  • Prepared remedial design documents
  • Installed 296 DPT injection wells at 3 different groundwater depth zones and 68 permanent remediation injection wells to target three separate hot spot areas
  • Injected 280,000 gallons of an emulsified oil substrate (EOS®)/sodium bicarbonate buffer solution, 320 liters of KB-1® bacterial culture, and anaerobic chase water (EHC®)
  • Monitored injection pressures, times and volumes
  • Performed maintenance of remedial systems and post-injection performance sampling
  • Achieved average 70% TCE decrease after initial 4-month injection event, prepared remedial action reports

Soil Excavation and Transportation & Disposal (SS-15)
To address PCB-contaminated soil at a transformer site, we performed a deep excavation, removing over3,500 tons of impacted soil, including areas along utility lines.  Our work at SS-15 included:

  • Excavated soil to as deep as 20 feet bgs, including up to 15 feet below the water table
  • Performed hydraulic containment measurements by pumping out/dewatering excavation cavities below water table and rainfalls events
  • Satisfied both CERCLA and TSCA requirements
  • Collected 100 post-excavation soil samples to verify impacted soil above cleanup limits had been excavated
  • Used field test kits to analyze soil samples for PCBs, allowing real-time in-field decision-making
  • Performed waste characterization  and managed T&D of soil to an approved offsite disposal facilities

Contract Value $3.5 Million

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Design-Implement, NAPL Treatment Pilot Study

Design-Implement, NAPL Treatment Pilot Study, IR Site 03 – Former Oily Waste Ponds, Parcel E, Hunters Point Naval Shipyard, San Francisco, CA

Designed and performed a pilot test to test a) in-situ thermal remediation (ISTR) using thermal conductive heating (TCH) to aggressively remove mobile non-aqueous phase liquid (NAPL) oily waste to protect San Francisco Bay, and b) in-situ solidification/stabilization to reduce NAPL migration to nearby ecological receptors in the San Francisco Bay.  The phases of work consisted of design, field implementation, data evaluation, reporting and recommendations.

  • Prepared planning documents, including a Work Plan, SAP/QAPP/FSP, Health & Safety Plan, Waste Management Plan, Environmental Protection Plan, QC Plan, and Radiological Material Management Plan
  • Pre-design characterization included tidal influence study and pump test (24-hour constant rate test, using 16 transducers) to facilitate remedial design
  • Soil and groundwater characterization, including 60+ soil and 13 baseline groundwater samples
  • In-situ Thermal Remediation (ISTR) using Thermal Conduction Heating (THC) Pilot Test
    • Designed remediation system for 46 heater wells, 46 co-located vacuum extraction wells, 14 MPE wells, 7 re-injection wells, 10 temperature and pressure monitoring points, and off-gas vapor treatment system including manifold piping network, vapor liquid separator/knock out tank, air heat exchanger, blower, and GAC
    • Installed an used 46 TCH heater wells to generate heat to produce steam agitation/ stripping and to reduce NAPL viscosity
    • Performed NAPL extraction from 14 MPE wells
    • Horizontal vacuum extraction wells at ground surface provided pneumatic control of upper zone during subsurface heating
    • Re-injected treated warm water into 7 wells to retain heat optimization system and provide hydraulic control
    • Design included two heat exchange units which allowed formation temperatures to reach 100 degrees C within the two weeks of start-up
  • Sampling and analyses to assess effectiveness
  • In-Situ Solidification/Stabilization (ISS) Pilot Test
  • Coordinated with USEPA Region 9, state EPA (DTSC and RWQCB-SF), and San Francisco Redevelopment Agency

Contract Value $3.7 Million

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Landfill Construction and Corrective Measures Implementation

Landfill Construction, U.S. Army Garrison, Redstone Arsenal, AL

  • Landfill construction and corrective measures implementation for an inactive 50-acre sanitary and industrial landfill
  • Construction Surveying of pre-construction conditions, landfill boundary, excavation and consolidation limits, soil placement and foundation layer, geosynthetic clay liner (GCL), final cover, and permanent survey and settlement monuments
  • Erosion Control – prepared SWPPP, implemented stormwater BMPs, including straw wattles and management of silt fencing
  • Earthwork/Excavation – Insight excavated approximately 64,000 cubic yards of landfill waste, to a maximum excavation depth of approximately 12 to 14 feet, and consolidated waste materials.
  • Placed a 24-inch foundation layer using soil imported from a borrow pit, then compacted, graded, and rolled to a smooth finish
  • Installed GCL
  • Placed a 12-inch imported clean topsoil cover layer and spread amendments to support vegetation
  • Performed final backfill and compaction, and performed geotechnical testing including density tests
  • Revegetation – Hydro-seeded the site, added soil amendments, and installed fiber rolls
  • Drainage Control – Excavated trenches, installed concrete drain inlets and corrugated metal pipe, backfilled and compacted trenches, and performed final grading of runoff diversion channels and riprap outfalls
  • Contract Value $1.1 Million
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