Clear Creek has managed the evaluation of groundwater supply resources for a confidential mining client in southeastern Arizona since the mid-1990s in order to identify and develop groundwater resources for their copper mines in the area.
Beginning in March 1995, during the permitting phase of the project, the client began field investigations to identify up to 5,000 gpm of groundwater resources to supply their first mine. Clear Creek staff participated in this field investigation, which was conducted in 3 phases:
* Phase I consisted of geophysical surveys and the installation of 17 test-wells.
* Phase II included the installation and testing of four (4) pilot-wells. This phase included several months-long, high rate pumping tests to test the aquifer’s sustainability
* Phase III included additional gravity and seismic geophysical surveys and the drilling of 27 boreholes (18 of which were completed as test-wells), and the installation of two (2) pilot-wells.
During the period from November 2007 through September 2008, Clear Creek conducted field work for another groundwater exploration project in the area for the same client. The extent to which groundwater resources in deep alluvial and/or bedrock aquifers at the project could be developed was contingent upon possible impacts to the shallow alluvium aquifer and surface water resources.
The project included the installation of 15 exploration borings, five (5) test wells, and two (2) piezometers. Clear Creek selected well sites based upon 1) a review of existing geologic and hydrogeologic data, 2) the results of surface geophysical surveys, and 3) discussions with the client.
A variety of drilling methods were employed during the groundwater exploration project, depending on the expected geology and function of the boring/well. Drilling methods used were direct rotary drilling, dual tube reverse circulation with air, and flooded reverse circulation drilling. Clear Creek managed subcontractors, logged the borings, and was onsite during all drilling and testing activities.
Borehole geophysical logging was conducted on several of the exploration boreholes. The typical geophysical logging suite consisted of caliper, natural gamma ray, electric, guard, sonic, and acoustic borehole imaging (ABI) televiewer. Airlift testing was conducted on each of the exploration borings. Constant rate aquifer testing was conducted on the test wells to allow for calculations of transmissivity. Clear Creek staff provided oversight during all geophysical and aquifer testing work, and they analyzed the data (including fracture orientation analyses based on the ABI data) to select and refine drilling locations.
Several promising targets were identified as a result of this work. The client suspended activities related to water resources evaluation for the project due to economic conditions at the time. However, should the project be resumed, our client is well-positioned to identify a sustainable water source for their project.