Considering the Ice Excavation Required to Establish and Maintain an Open Ice Pit
Publication: Journal of Cold Regions Engineering
Volume 28, Issue 3
Abstract
Several factors are increasing the likelihood of open ice pit mining adjacent to the Greenland ice sheet. This study employs a fully transient one-dimensional (1D) (depth-averaged) ice flow model, which includes a first-order longitudinal stress gradient approximation, to estimate the ice excavation required to establish and maintain an open ice pit. An idealized open ice pit geometry and purely deformational flow are assumed. A Monte Carlo approach is used to quantify the cumulative uncertainty in total ice excavation resulting from four key parameters: (1) ice temperature, (2) ice thickness, (3) equilibrium line altitude, and (4) surface mass balance gradient. Two scenarios of ice pit slope (2H:1V and 3H:1V), excavation method (constant and progressively steepening slope), and surface ablation enhancement ( and ), are considered. Total ice excavation is more sensitive to parameters controlling deformational velocity (1 and 2) than parameters controlling surface mass balance (3 and 4). Enhancing surface ablation by a feasible amount offers the potential to decrease total ice excavation by over mine life. Progressively steepening the ice pit slope offers the potential to limit variability in ice excavation rate, and reduce velocity and ice thickness gradients conducive to crevasse formation.
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Acknowledgments
The author thanks Tad Pfeffer for bringing this curious engineering problem to his attention, and Sam Colbeck for reviewing an earlier version of this manuscript. The author also thanks two anonymous reviewers and editor Jon Zufelt for their assistance in improving this manuscript. This paper is published with the permission of the Geological Survey of Denmark and Greenland.
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Published In
Journal of Cold Regions Engineering
Volume 28 • Issue 3 • September 2014
Copyright
© 2014 American Society of Civil Engineers.
History
Received: Feb 21, 2013
Accepted: Jan 29, 2014
Published online: Apr 7, 2014
Published in print: Sep 1, 2014
Discussion open until: Sep 7, 2014
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