Archives: Projects

FORMER MINE SITE PROCESS AREA RADIOLOGICAL REMEDIATION

ENTACT conducted three remedial actions at a former copper mine site in Nevada. The remediation required the removal of 6,000 tons of radiological soil, 21,000 feet of “transite” asbestos pipe, and the capping of 25 acres of tailings in two former evaporation ponds. All actions were completed in compliance with an EPA Administrative Order on Consent, ahead of schedule, and with no injuries to onsite personnel. The EPA “was particularly impressed by the strong emphasis placed on worker health and safety throughout the project.”

FORMER MGP SITE IN-SITU SOLIDIFICATION AND STABILIZATION

ENTACT completed site remedial work and in-situ solidification and stabilization (ISS) of impacted soils at an 8-acre former manufactured gas plant (MGP) site. The project was situated near industrial, commercial, and residential properties; community parking areas, a recreational park; and water district facilities, including water supply wells. Remediation included excavation, transportation, and disposal of 52,000 tons of MGP-impacted soils; in-situ solidification and stabilization of approximately 168,000 cubic yards of impacted material using cement-bentonite-slag grout; construction of a temporary containment structure

FORMER WOOD TREATING SITE CORRECTIVE MEASURES IMPLEMENTATION

ENTACT implemented corrective measures at a 52-acre former wood-treating facility that produced creosote-treated railroad crossties. We installed a 2,200 linear foot soil-bentonite slurry wall to a depth of 45 feet below surface grade and permeability of 1×10-7 cm/sec to contain the source area and control groundwater migration from it. ENTACT also excavated and consolidated 17,000 cubic yards of polycyclic aromatic hydrocarbon and phenol-impacted surface soils, subsurface soils, and sediments and dewatered and backfilled a former water supply pond located in

PICKLE POND REMEDIAL AND HABITAT CONSTRUCTION

Pickle Pond is a nine-acre urban pond created by the construction of a railroad embankment that cut off part of Barker’s Bay. The pond is in the St. Louis River lower estuary, sheltered from the main bay, and provides habitat to waterfowl, beavers, otters, and other wildlife. White Lake Dock & Dredge, Inc., a division of ENTACT, LLC, was responsible for dredging more than 16,000 cubic yards of contaminated sediments consisting of fine-grained silty clays from a shallow draft area

LNG EXPORT TERMINAL GROUND IMPROVEMENT

ENTACT performed soil improvement at this 1,000-acre site in preparation for the development of a Liquefied Natural Gas (LNG) export terminal. The project site is at an ideal location, situated on a ship channel that connects with the Gulf of Mexico. It features deep-water access, proximity to plentiful gas supplies, and ease of transport for buyers. The scope of work included soil improvement of 411,000 cubic yards of soft saturated clay to depths ranging from 4.0 to 8.5 feet, within

LNG LIQUEFACTION SOIL STABILIZATION

The Client’s project included expanding a liquefied natural gas (LNG) terminal to accommodate three LNG trains, a typical gas pretreatment unit, and a dock. Before construction could begin, the ground needed to be reinforced to support the complete turnkey LNG facility. ENTACT performed mass stabilization of over 2.3 million cubic yards of soft dredged sediment and fill soils. We accomplished in-situ stabilization with 16 excavators working atop timber mats, and the pneumatic delivery of Portland cement via custom-fabricated conveyance boxes.

LNG EXPORT FACILITY SOIL IMPROVEMENT

In preparation for future construction at this liquefied natural gas (LNG) export facility, ENTACT improved the soil in the expansion area to facilitate equipment access and support perimeter storm protection and levee system construction. ENTACT’s scope included soil improvement of approximately 1.7 million cubic yards of soft saturated dredged clay, filled to depths ranging from 3.0 to 6.0 feet within various areas of this site. We utilized Type I-II Portland cement to achieve a shear strength of 1,800 psf for

FORMER CHROMIUM ALLOY AND RADIOLOGICAL SUPERFUND SITE

ENTACT was engaged to perform a four-phased remedial action project to support the decommissioning of this former glass and super alloy additives manufacturing facility. Due to historical and metallurgical operations conducted at the site, metals and radiological impacts were present in soil and sediment on the property and off-site, consisting of wetlands, a stream channel, and wooded upland areas. Phase 1 of the project addressed the impacted materials on the property limits, and Phases 2, 3, and 4 addressed the

Aerial view of an active project site with water, bridges and buildings in the background

CHEMICAL AND RADIOLOGICAL REMEDIATION

ENTACT is performing an ecological restoration of 100+ acres previously home to several chemical manufacturers, a clay mining operation, and a disposal area for impacted soils and dredge spoils. The restoration plan includes creating a 14-acre open-water pond, 40 acres of wetland mitigation, 55 acres of upland enhancement, and close to two miles of public walking trails and boardwalks. The first phase remediated impacted sediments from a 4.9-acre lake on the site. Benzaldehyde, bis (2-ethylhexyl) phthalate (BEHP), formaldehyde, and PCB

ACTIVE STEEL MILL CREEK AND DITCH PCB SEDIMENT REMOVAL

ENTACT partnered with our Client to implement a phased solution to remove the impacted sediment and restore the river and its surroundings for a nearby community. Work included remediating 3,000 linear feet of ditch line and 5,600 linear feet of creek channel; transporting 178,500 tons of polychlorinated biphenyl-impacted sediment, clay, and native materials off-site for disposal; and treating and filtering 4 billion gallons of water using an onsite water treatment system. In addition to meeting our Client’s objectives, we managed

FORMER PHOSPHATE FERTILIZER SITES REMOVAL ACTION

ENTACT performed remediation of nine former phosphate fertilizer production and manufacturing sites to address lead- and arsenic-impacted soils, sediment, and groundwater. ENTACT partnered with our Client to navigate the complexities and requirements of this multi-facet remediation project. Sites were in commercial, residential, and industrial zones. Tidally influenced areas were located adjacent to navigable waterways, marshes, uplands, and active rail lines and major highways. While scopes varied in magnitude at each site, work typically involved excavation and off-site disposal activities, sediment