160 likes | 170 Views
Edwardsport IGCC Mine Stabilization Project. Construction at the Largest Remediation Mine Grouting Project in North America. Presented by: Howard Concrete Pumping Co., Inc. • Lynn Crayne • Frank Howard III. Acknowledgments. Jeff Fields, Senior Engineer
E N D
Edwardsport IGCC Mine Stabilization Project Construction at the Largest Remediation Mine Grouting Project in North America Presented by:Howard Concrete Pumping Co., Inc. • Lynn Crayne • Frank Howard III
Acknowledgments Jeff Fields, Senior Engineer Jim Sublett, Senior Sourcing Specialist GAI Consultants, Project Designer Bob Turka, Senior Project Manager
Mining History at the White River Mine • Mined in the 1920s and 1930s using the room and pillar method • No evidence of retreat or split pillar mining • Mine was flooded • To this day • The pillars are mostly in place • Sinkholes onsite indicate shallow cover and mine subsidence
The Existing Edwardsport Plant • A 160-megawatt coal combustion plant • The original unit was built in 1918 but is no longer operational • Three other operating units were built between 1944 and 1951 • It currently operates at a fraction of its capacity Jack Stultz, General Manager of Duke Energy Indiana, will be able to update you to the benefits of the new proposed facility.
Construction Overview • Construction includes grouting beneath nearly ±30 acres of the proposed IGCC facility • Drilling into the abandoned deep mine using both track-mounted and tire-mounted drill rigs • Grout is to be manufactured onsite by two volumetric mixing plant • From the point of manufacture, grout is pumped by a Schwing BPL 4000 pump via 4-inch steel slick line to second pump at the point of placement • The second pump has a 39-meter placing boom with an attached tremie pipe for ease of placement
Construction Overview (Continued) • All materials for the grout are delivered and stored onsite, including cement, sand, and fly ash • Fly ash to be mined from the existing fly ash pond onsite • Cement from local plant • Water for the grout manufacture is obtained from the mine pool • An observation well is used to monitor the mine pool height and water pH • If the mine pool rises one foot, a pump installed into the mine is used to remove mine water to retention pond • Estimated completion date is February 2008
Drilling Specifics • The construction includes nearly 2,500 boreholes • Holes are approximately 6-inch in diameter • On average, they are 45 to 50-feet deep • That’s over 115,000 linear feet of drilling • Holes are cased to the top of rock using plastic (PVC SDR 35) casing • Casing is 6 inches in diameter and is manufactured in 10 feet sections • Casing is installed to an average depth of 20 feet
Drilling Specifics (Continued) • Holes are plotted on a grid with 25-feet spacing • Approximately 220 holes are drilled on angle • Angles of inclination vary from 22º to 45º • Angles are necessary because of site access issues due to existing 345 kV power lines
Angle Drilling Beneath Power Lines Leave a blank slide for the insertion of a typical boring log to be inserted by us
Grouting Specifics • There are two types of grout to be used: • Barrier Grout – to be used on the perimeter of the mine limits • Consists of Type I cement, sand, Type “F” fly ash, and water • Has an 8-inch slump • Production Grout – to be used on the interior • Consists of Type I cement, Type “F” fly ash, and water • Has a 60-second flow
Grouting Specifics (Continued) • All grout has a design strength of 200 psi at 28 days • Actual design strengths are averaging 450 psi at 28 days using cubes for compressive testing with an onsite lab • Total grout quantity estimated for the project’s completion is 180,000 cubic yards • Average production is 2,000 cubic yards per day • Fly ash for the grout manufacture is mined and dried from the existing fly ash pond • Increased pond storage is a secondary benefit for Duke Energy
Key Points • The existence of abandoned deep mines creates surface subsidence problems which complicate development in many regions of the country • As development locations become limited, mine stabilization construction is becoming more common • Mine stabilization construction can effectively allow development on abandoned mine land • Even for very high-value structures
Thanks to The Indiana Society of Mining and Reclamation Special Thanks to: Colleen Baughman Ron McAhron