An integrated assessment of potential granular aggregate resources in Northwest Territories
Authors: Smith I R , Lesk-Winfield K 
Published: January 2011

Granular aggregate (e.g., sand, gravel, boulders, and crushed bedrock) is critical to all manner of community, regional, and commercial infrastructure development including roads, airstrips, concrete production, petroleum well and building pads, and pipelines.
Typically, granular aggregate is mined from glacial deposits such as eskers, kames, and sub- and pro-glacial meltwater channels; it can also be mined from modern or paleo-river deposits such as raised terraces. As the greatest economic cost of granular aggregate resources is typically associated
with its transportation, and this cost increases exponentially with distance, undertakings that identify new potential sources in proximity to communities and prospective infrastructure development projects is regarded as being of particular benefit.
This study uses drillers' logs from past seismic operations throughout the Northwest Territories as a means of identifying potential surface and subsurface (buried) granular aggregate resources. During the auger drilling of seismic shotholes, drillers logged the earth materials they were drilling
through at varying degrees of resolution and accuracy. Past success using seismic shothole drillers' logs to identify a large buried granular aggregate deposit in northeastern British Columbia has demonstrated the efficacy of this type of investigation. Using a database of &amp;gt;275 000
archival shothole drillers' log records (Open File 6049), this project has queried, sorted, and interpreted the data from which databases and shapefiles of "gravel" (including boulders and rocks), "gravel + sand" and "sand" deposits have been integrated into a regional Geographic Information System
(GIS). Relevant data from a geotechnical borehole database (Smith, 2005) and a separate database of seismic shothole drillers' logs from the Mackenzie Delta region (Côté et al., 2003) has also been interpreted and integrated into the GIS. This publication also includes granular
aggregate-associated map polygons (e.g., glaciofluvial deposits, alluvial terraces) extracted from existing surficial geology maps. At present this is confined to the northern part of the Mackenzie corridor (many more surficial geology maps are being completed for the central and southern part of
the Mackenzie corridor, and will be integrated into a revised publication at a later date). The benefit of including the map polygon data is that it can be used to confirm or question the identification of potential granular aggregate deposits from coincident shothole records; it also can give a
sense of the potential geographic extent of what is otherwise point-source shothole data. The GIS created by this project is designed to give the user a visual sense of the distribution and size of potential granular aggregate deposits, while at the same time providing the ability to search and
query the actual records throughout the geographic extent of the data. In all cases, users are cautioned that seismic shothole-associated deposits identified in the GIS should only be considered "potential" granular aggregate resources - all deposits require field verification, as well as a proper
assessment of their sedimentological and lithological characteristics prior to their engineering application, or inclusion as part of a regional resource inventory. That said, past success in using this kind of information to prospect for granular aggregate resources, and the shear volume and
geographical extent of new information provided by this project is likely to make this a particularly invaluable resource for the Northwest Territories.
Purpose: Produced as part of Natural Resources Canada's Secure Canadian Energy Supply Program, Northern Energy Development - Mackenzie Valley Pipeline project and Program of Energy Research and Development (PERD) Pipelines Program 1.2.5