|
Massive Seepage Reduction
|
Limestone Quarry, Eastern US
|
| |
| August 1997 - February 1999 |
| |
During a routine mining operation in an existing limestone
quarry, a karstic feature was encountered some 200 feet below the level
of the Shenandoah River. The hydrologically dormant feature was connected
to the river and soon became active causing excessive inflows into the
quarry. The inflow was over 50,000 gpm which surpassed the capacity of
the quarry dewatering system and extensive flooding occurred.
It was determined that karsts, as high as 70 feet were acting as direct
river water seepage conduits. Geosystems was responsible for assessing
the geological and hydrological conditions, guiding and interpreting
the site investigation programs and helping establish contractor selection
criteria for the owner. During the work, Geosystems provided project
design, management, coordination, and technical services. Upon the
completion of each phase of the work, Geosystems also wrote detailed
technical reports.
Special techniques that were designed and supervised by Geosystems
included:
- Hydrothermal mapping to differentiate between river inflow and
static groundwater.
- Hot bitumen grouting in conjunction with cement
grouting. This type of grouting technology was necessary to stop
the major seepage pathways.
- Compaction grouting to stabilize the overburden and low flow karsts.
- Downstream
well pH monitoring to determine the amount of cement washout during
grouting operations.
- Permeation grouting with custom tailored water
repellant cement based grouts in areas with low flow.
- Custom designed dual zone bitumen stingers used to provide
simultaneous injection of bitumen and cement based suspension
grouts to targeted
zones.
- By the conclusion of construction, a grout curtain 1050
feet long by 200 feet deep was successfully installed
and the
quarry inflow
from
the river was successfully reduced back to production
levels. Upon completion of the project in December 1998, the river
inflow had
been stopped.
|
| |
Contact
|
Available on request. |
| |
Technical Papers
|
Bruce, D.A.,
R.P. Traylor, and J. Lolcama. (2001). “The Sealing of a Massive
Water Flow through Karstic Limestone.” Foundations and Ground Improvement,
Proceedings of a Specialty Conference, American Society of Civil Engineers,
Blacksburg, VA, June 9-13, Geotechnical Special Publication No. 113,
pp. 160-174. |
Bruce, D.A., Chan, P.H.C., and Tamaro,
G.J. (1991). “Design Construction and Performance of a Deep Circular
Diaphragm Wall.” Proc. ASTM International Symposium on Slurry Walls,
Atlantic City, NJ, June 27-28, 12 pp. |
Bruce, D.A. and Pratt, J.W. (1990). “A
Hydraulic Cut-off through Unconsolidated Mine Dump Material.” Association
of State Dam Safety Officials, 7th Annual Conference, New Orleans, LA,
October 14-18, pp. 417-430. |
|
|
