Core Repository and Exploration Records

The Maine Geological Survey maintains a repository of geological drill cores and samples for research purposes. These collections are focused on hard rock mineral resources and represent projects widely scattered about Maine in both time and space. Perhaps 100,000 feet of core representing millions of dollars in recovery expense are preserved in the facility. All cores and related documentation were donated to the State at various times by their rightful owners and are now considered State records, available for public inspection. The map shows townships where Maine Geological Survey has cores, or in some cases both cores and core logs.

Core Locations

  • Cores shown on the map were approximately located using project maps from various exploration programs. Location information was georeferenced using ArcMap, USGS topographic quadrangles, and aerial photography. Locations should be considered approximate and for general reference only.

View Map Full Screen

Core Logs

  • As rock core is obtained by drilling, it is examined by a geologist who keeps a record, or log, of features of interest along the length of the core. Such drill logs are paper records which may be best used to direct investigators to particular segments of the rock core for further study or analysis, and to connect structural or mineralogical features at depth from one hole to another.
  • The Maine Geological Survey has copies of many such exploration logs. Some of the rock core in the repository has corresponding logs, but there are also some cores for which we do not have logs. Also, there are some logs in our records for which we do not have rock core.
  • Individual core logs, maps and cross sections have been scanned for many of the exploration projects and consolidated into project files. The files may be viewed or downloaded by clicking on the interactive map above or in the tables below.

Driller Project Project File Town(s)


Core Repository Box Inventory

  • Core is stored in boxes arranged by drilling depth in the repository locations listed below. The data table can be used to search for core and verify its location by correlating the Core Building and Footprint Number values with the building diagrams accessed by clicking the Core Building link. Contact MGS to make arrangements to review any of the core.
  • Core Building Layout Diagrams:
Driller Project Project File Town(s) Hole Number Core Building Footprint Number Footprint Type Shelf Stack Box Number Depth Top Depth Bottom Location Map Drill Logs Comments
Driller Project Project File Town(s) Hole Number Core Building Footprint Number Footprint Type Shelf Stack Box Number Depth Top Depth Bottom Location Map Drill Logs Comments