Permafrost

Given the risks of potential deterioration in the integrity of containment structures and
enhanced metal leaching associated with permafrost thawing, great caution must be taken in
devising mine waste management schemes that rely heavily on the persistence of frozen ground.
The possibility of a warming climate leading to permafrost degradation must be duly
considered in developing a proper strategy for a particular site, especially those located in
terrains with discontinuous or scattered permafrost.
Key Words:Thawing permafrost, tailings stability, metal leaching, mine waste management
94
Cryosphere and permafrost change resulting in slope instability in
Hindu Kush and Western Himalaya
John Shroder, Michael Bishop, Henry Bulley, Umesh Haritashya, Jeffrey Olsenholler
(GLIMS (Global Land Ice Measurements from Space) Regional Center for Southwest Asia (Afghanistan and
Pakistan); Department of Geography and Geology, University of Nebraska at Omaha, Omaha, NE 68182
USA )
Abstract: Manifold climate changes in Quaternary time are well known to have influenced
landform stability. In the Hindu Kush and western Himalaya GLIMS researchers are
identifying past and present-day examples of slope instabilities resulting from combinations of
monsoon fluctuation and ancient and modern permafrost degradation in bedrock and
regolith-covered slopes, as well as downwasting glaciers that debuttress valley walls, and
increased melt-water breakout floods that undercut valley walls. Increased global warming
may be causing monsoon fluctuations and multiple instabilities in cryospheric/permafrost
systems in high mountain regions that will result in many more natural hazards for residents
and adventure tourists to deal with, while at the same time providing opportunities to study such
dangerous phenomena. In the Afghanistan Hindu Kush, because of ongoing political
uncertainties significant fieldwork is limited. Landsat and ASTER imagery, however, coupled
with older topographic maps from Soviet and Anerican government sources, plus prior field
assessments, enable GLIMS researchers to pinpoint cryospheric changes that are indicative of
the overall condition of ice resources that control downstream water resources in a chronically
arid area. In the Pakistani Karakoram Himalaya we are especially interested in cryospheric
controls of slope stability and instability, as well as in measurable fluctuations of debris-covered
glacial ice that we can detect in satellite imagery, coupled with field assessments. In summer
2005 in the Shigar, Braldu, and Baltoro valleys we investigated four major mass-movement
complexes (Ghoro Choh rock avalanche complex, Busper sackung, Gomboro slope failure
complex, Urdokas rockslide complex) that are associated with canyon-wall debuttressing,
undercutting, and permafrost degradation resulting in reduced rock strength. The 3-4 km of
relief, coupled with steep slopes, and high to intermediate magnitude and frequency snow and
rain storms provide considerable potential, gravitational, kinetic, and thermal energy sources
that drive the varied mass-movement processes. The products of such mass movement are
ubiquitous, including failure of massive crystalline rock (gneisses, metasediments, granites) to
depths of hundreds of m, piling up considerable mass on valley floors and sidewalls, causing