Mt. Princeton, Colorado

Key Project Information

Purpose: Geothermal Exploration for Electric Power Generation
Method: Magnetotelluric (MT) and Shallow Temperature Probe (STP) surveys / Broadband Magnetotellurics (BMT) and Low-frequency Magnetotellurics (LMT)
Location: Mt. Princeton, Colorado Client: Mt. Princeton Geothermal, LLC
End-User: Mt. Princeton Geothermal, LLC
Dates: 2011 - 2012
Main Survey Area: 14 km2
Extended Survey Area: 32 km2
Total number of MT Stations: 164
Total number of STP Stations: 77
Client Reference: Mr. John H. Held Mt. Princeton Geothermal, LLC 5005 Christensen Dr. Littleton, CO 80123 (303) 748-0001 (M) (303) 789-7604 (O) hheld@burt.com

Project Summary

Dewhurst Group, LLC (DG) was competitively selected by Mt. Princeton Geothermal, LLC to confirm resource potential for geothermal power generation. DG exclusively provided all 3-D resistivity imaging and shallow temperature information used for the project. Mt. Princeton, CO is located approximately 26km Northwest of Poncha Springs, CO, 14km Southwest of Buena Vista, CO and 119km West of Colorado Springs, CO. DG was responsible for locating sub-surface structure, potential geothermal source, and plumbing systems for commercial exploitation. Survey activities were coordinated with Mt. Princeton Hot Springs Resort.

Statement of Work

Work was performed using a phased approach:

™™Phase 1: Test and Design

  • Calibration, geo-electric strike and dimensionality analysis
  • Survey Design

™™Phase 2: Field Work

  • 164 BMT stations (soundings)
  • 77 Shallow temperature probe observations
  • Near-real time processing in the field

™™Phase 3: MT Data Analysis

  • Calculation of transfer functions
  • 1-D station inversions
  • 2-D profile inversions
  • 15 BMT Profiles

™™Phase 4: 3-D modeling and Final Report

  • 3-D renderings from 1-D results (e.g., 1.5-D inversion)
  • 3-D renderings from 2-D results (e.g., 2.5-D inversion)
  • 3-D unconstrained inversion

™™Phase 5: Comparison of all results for robust resistivity imaging and interpretation.

Environment, Safety, and Cultural Awareness

DG is committed to minimally disrupting the land, stimulating the local economy and respecting native culture. DG’s methods 1.) are non-ground disturbing, 2.) did not require an Environmental Impact Statement under the National Environmental Policy Act of 1969 and 3.) qualified for a casual use permit within the Bureau of Land Management (BLM). Further, DG coordinated all field work with the State of Colorado and private stakeholders. DG hired and trained three previously unemployed Jemez Tribal Members. Despite adverse winter weather conditions, no significant injuries were incurred during this accident-free survey.

Schedule and Budget

All field work was completed within six weeks and final results delivered within 60 days of data acquisition. All work was completed with a multiple-survey discount. Survey was coincidental with survey performed at Poncha Springs, CO.

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