Laserfiche WebLink
demonstrated when the well completion report shows that the cementing of the annulus <br />between the well casing and the borehole is adequate to prevent fluid movement into a <br />USDW through vertical channels adjacent to the injection well bore. Upon completion of <br />the proposed injection well, Permittee submitted a Well Construction and Test Report to <br />the Colorado State Engineer. The same report was submitted to EPA as part of the Class <br />V permit application. According to a December 23, 2010 email from an EPA official, the <br />Region 8 UIC program has adopted the State Engineer's requirements for the proposed <br />injection well, and "the injection well was constructed according to the State Engineer's <br />requirements." The completion report for the proposed injection well indicates that the <br />well was grouted with 829 gallons of "Bent-cem" with a density of 13 lbs., and that the <br />grout was pumped into the well using the Halliburton method of placement. This appears <br />to be a sufficient volume of grout to seal the annulus. However, the grout mix is also an <br />important factor to consider when determining a well's mechanical integrity. The <br />Colorado State Engineer's "Water Well Construction Rules" contains a "Table 3 - <br />Grouts" which defines approved grouts for sealing well annuli. For a pumped cement- <br />bentonite grout to be approved, it cannot contain more than 8% bentonite per dry weight <br />of cement. Section 10.5.1 of the rules requires that "the volume percent of each additive <br />used in the grout mixture shall be reported on the well construction report." The well <br />construction report submitted by Permittee does not specify the volume percent of <br />bentonite used in the grout mixture, and therefore is not in compliance with the State <br />Engineer's requirements. In addition, the addition of bentonite to a grout mix allows the <br />contractor to use less cement and more water (bentonite acts to keep the cement <br />suspended in the mix until setting.) As the percentage of bentonite in the mix increases, <br />6