Project Name

Project Location

Client / Division

Grapevine Mine Reclamation Project

Jefferson County, Colorado

Colorado Mine Land Reclamation Department

David H. Scriven was the design engineer and construction manager of the reclamation of the Grapevine Uranium Mine, Jefferson County, Colorado. He was responsible for the radiometric survey, design of clay lined pit for uranium dump rock disposal, shaft and adit closure. The assignment also included reconstruction of approximately º mile of Sawmill Creek with compacted embankment, riprap protected slope and toe drain installation.

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AML Projects 16-A, 16-D and 16-E-2; Gas Hills Uranium Reclamation

Fremont and Natrona Counties, Wyoming

Wyoming Department of Environmental Quality Land Quality Division

David H. Scriven was the geotechnical consultant for the reclamation of the John Gunnel, Veca Pit, B Pits, and Tee Pits and a radiometric consultant for the reclamation of the B and Tee Pits. He was responsible for the subsurface geotechnical and radiometric investigations, stability analyses of the highwalls and surface radiometric surveys of the spoil piles and surrounding areas. As part of the Design Investigation Report, he coordinated the geotechnical testing program and performed analysis associated with the backfill operations of the reclamation plan and prepared radiometric isopach maps of the spoils and areas surrounding the pits showing various levels of radium 226 contamination.

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AML Projects 16-C; Gas Hills Uranium Reclamation

Fremont County, Wyoming

Wyoming Departement of Environmental Quality Land Quality Division

David H. Scriven was project manager for the reclamation of the North Rex and Utah Pits and the Rox, Thunderbird and Atlas-Peach Underground uranium mines. He was responsible for subsurface geotechnical investigations, reclamation designs and bid document preparation. He coordinated the work of several sub-consultants performing ground and surface water studies, geomorphologic investigations, wildlife and plant studies, radiometric surveys and revegetation designs.

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Riley Pass Reclamation Project

Hardin County, South Dakota

Custer National Forest Billings, Montana

David H. Scriven was project manager for the investigation and design for the reclamation of the Riley Pass Uranium Mine, Hardin County, South Dakota. He managed a team of soil scientists, geomorphologists, biologists and health physicists to develop design alternatives for the project. The Riley Pass Mine was a surface mine, circa late 1950's, mining uranium associated with a thin coal seam overlying the rimrock. Spoil material was pushed over the rimrock creating an unstable and highly erosive surface. Several highwalls were left standing and ponded areas were created in the spoil piles. The project included the development of several reclamation alternatives. The alternatives were presented to the client to determine the one most suitable to their needs. Final design and bid documents were then prepared for the reclamation.

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Surface Drainage Design and Landslide Stabilization; Seneca No. 1 Mine Reclamation Project

Routt County, Colorado

Colorado Department of Narural Resources/Mined Land Reclamation Division

Several final pits in the Seneca No. 1 Surface Coal Mine were abandoned in the 1960's without being reclaimed. In addition, a progressive landslide aggravated by the abandoned mine land conditions threatened a county road, private property and a major stream course. The reclamation design included routing storm runoff through the reclaimed areas which were typically situated in steep terrain. The construction of numerous drop structures, rip rap lined channels, subsurface drains and compacted dikes was required. Approximately 200,000 cubic yards of earthwork was involved in the project. David H. Scriven was staff engineer for the field investigations, analysis and designs for stabilization of the landslide and the reclamation of the mined-out areas. Mr. Scriven assisted in the preparation of construction bid documentation (drawings and specifications) and assisted the State of Colorado in the pre-bid conferences and bid evaluation (the project was divided into two construction contracts). Mr. Scriven was on the project's construction management team.

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Client / Division

Superior AML Project 6B

Sweetwater County, Wyoming

Wyoming Department of Environmental Quality Land/Quality Division

The Town of Superior is located in a major turn-of-the-century coal mining district in southwestern Wyoming. Several hazards to the public associated with the abandoned underground coal mines had to be addressed. Our work included the following investigations, design, development of construction documents and construction management: o Subsidence control by grouting beneath commercial structures and an undermined public school. A specialized grouting technique and grout mixture were used beneath the school because of the nature of the trough-type rock collapse and the weakened soils. The ground improvement involved the use of Tube-a-Manchette grout casing which allows for considerable control of the "zone" in which the grout is injected. The cement-fly ash grout base was designed for the special ground and injection conditions by incorporation of admixtures for strength (silica fume), fluidity and plasticity (polyethylene glycol), and set retardant (sugar). o Closures for 32 abandoned coal mine openings (exposed adits and inclines, sink holes into mine workings). o Reclamation of four coal waste areas. o Closure of a concrete lined ventilation shaft.

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Client / Division

Geotechnical, Hydrological and Mining Engineering Support

Clear Creek/Central City Site RI/FS

Camp Dresser & McKee Inc. (CDM)

D.H. Scriven was staff engineer for the geotechnical subcontractor to CDM on the Remedial Investigation/Feasibility Study at five Superfund sites in Clear Creek and Gilpin Counties, Colorado. The sites included mine waste rock and tailings dumps, several adjacent to perennial streams. Mr. Scriven performed subsurface investigations (borehole drilling and sampling), piezometer installations, sample selection for physical testing, analysis of laboratory results and slope stability analysis. Stable configurations were determined and alternative remedial methods were evaluated. A comprehensive geotechnical report was prepared in support of and complementary to CDM's RI/FS efforts.

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Project 16-III, Gas Hills Uranium District

Fremont County, Wyoming

Wyoming Department of Environmental Quality

D.H. Scriven performed the baseline investigations, analysis, designs and developing the bid documents for the reclamation of two abandoned uranium pit mine and spoil areas, and three abandoned underground uranium mines. Reclamation included elimination of public hazards such as highwalls, unstable ground and water hazards, and containment of toxic and radioactive materials. Underground mine sites reclamation includes sealing of mine shafts and containment of toxic and radioactive materials.

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Reclamation Plan and Bond Calculation

Green River, Wyoming

General Chemical Corporation

WSMC completed the five year reclamation plan and reclamation bond calculations to be presented to the Bureau of Land Management and the Wyoming Department of Environmental Quality for General Chemical Corporation. The study included designing the final contour of the surface disturbance, developing methodology for reclaiming tailings and evaporation ponds and identifying soils for cover material and topsoil. In addition, costs to reclaim the property to grazing land were calculated. The study resulted in lowering the in place reclamation bond by nearly 50%.

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Project Location

Client / Division

Pond 1 Modification

Green River, Wyoming

Tenneco Soda Ash Company

WSMC provided design and permitting services for Tenneco Soda Ash Company to modify their evaporation pond and increase its storage capacity. The assignment included design of two auxiliary embankments with cementacious grout curtains for seepage control, a five to six foot downstream raise of the main embankment including installation of a chimney drain, and the design of two interceptor trenches and pumpback system. The modification constructed during the summer of 1992, added approximately 1300 acre feet of storage capacity to the facility. The project also included installation of eight monitor wells around the perimeter of the facility and five piezometer wells in the embankment.

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Due Diligence Environmental Investigation

Casper, Wyoming

Malapai Resources

David H. Scriven was the project manager for the due diligence environmental investigation at the Iragaray and Christensen Ranch in-situ uranium sites and the Willow Creek research and development site. The investigation was completed prior to the sale of Malapai Resources to Total. The project included complete testing and environmental assessment of all plants, ponds and leach fields. Staff included a wide variety of engineering and scientific disciplines to cover all aspects of the environmental assessment of the site including health physicists, biologists, hydrologists, soil scientists and environmental engineers.

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Pennsylvania Mine

Clear Creek County, Colorado

Colorado Mine Land Reclamation Department

David H. Scriven was the lead engineer in charge of designing an acid mine drainage collection and neutralization system for the Pennsylvania Mine. The system required the capacity to collect transport and neutralize 100 GPM of acid mine water (pH 3.0). The project included the relocation of several 1880's patented mining claims, the design of a collection and piping system, a turbine mill, a 24-hour detention pond and a five acre man-made wetland to complete the neutralization prior to discharge of the water into Peru Creek.

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Shaft and Adit Closures; Abandoned Mines Lands Program

Denver, Colorado

Colorado Mined Land Reclamation Division

David H. Scriven was Project Design Engineer in the closure of several hundred shafts and adits throughout Colorado's gold and silver mining districts. He developed several techniques in shaft closures which both protected the environment and preserved the historical values of the districts. He authored the article "Polyurethane Foam used in Shaft Closures" printed in Mining Engineering detailing the method to preserve headframes while sealing the shafts. Shaft closure designs were always sensitive to future mining activities. Many designs included locked grated doors which provided safety from accidental entry but allowed access for future exploration projects. On most of these projects, Mr. Scriven did the initial investigation, provided the design and technical specifications, conducted the pre-bid tours and performed construction management for the projects.