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<br />RATIONALE FOR WITHDRAWAL
<br />(Howe Pit, Permit M-78-052, 12/12/01)
<br />I. On September 14, 2001 the Division of Minerals & Geology sent a letter to Mobile Premix Concrete, Inc. (MPC)
<br />stating reason to believe (RTB) the Howe Pit operation was in violation and citing flood related damage that had
<br />occurred on and adjacent to the Howe Pit on May 5, 2001 when a levee failed and stating that the Division believed
<br />these damages resulted from MPC's installation of the relocated Bull Seep channel in a location and configuration other
<br />than that approved in the Mined Land Reclamation Permit. The letter further cited MPC's failure to properly install other
<br />associated drainage convol structures as required by the permit. In its RTB letter the Division described a possible
<br />violation of C.R.S. 34-32.5-116(4)(1) and Rule 3.1.5(3) for failure to protect areas outside [he affected land from slides
<br />and other damage and C.R.S. 34-32.5-116(4)(h) and Rule 3.1.6(1) for failure to minimize disturbance [o the prevailing
<br />hydrologic balance of [he affected land and of the surrounding area and to the quantity or quality of water in surface and
<br />groundwater systems both during and after the mining operation and during reclamation. A Formal Public Hearing was
<br />scheduled for October 17, 2001 in Canon City.
<br />2. At the October 17, 200] meeting the Mined Land Reclamation Board continued the scheduled hearing at the request of
<br />the Division. The basis for [he continuance was that the Division needed additional time to review technical information
<br />submitted by the Operator on October 15, 2001 and additional time to evaluate information collected during a site
<br />inspection conducted by the Division on October 15, 2001. Also at the October 17, 2001 meeting the Board conducted a
<br />Formal Public Hearing for a separate possible violation to the Howe Pit permit. During that hearing, the Board found a
<br />violation of Section 34-32.5-1 l6(I ), C.R.S. for failure to perform reclamation according to the reclamation plan.
<br />Subsequently, the Board issued Notice of Violation MV-2001-041 and ordered the payment of civil penalties and
<br />completion of corrective actions. This rationale for withdrawal in no way applies to, or affects Notice of Violation MV
<br />2001-041 found by the Board at the October 17, 2001 hearing.
<br />3. The technical information provided by the operator on and following October 15, 200ldemonstrates that there was a
<br />pre-existing breach in the levee (this levee is referred to by the Operator as a repaired riverbank - no[ a levee) at the
<br />south end of the May 5, 2001 failure area and presents a case that the pre-existing breach was the primary cause of levee
<br />failure on May 5, 2001. The information provided indicates that overtopping flow events from the South Platte River
<br />during July and August of year 2000 likely created the pre-existing breach. The Division has now concluded that the pre-
<br />existing breach was the primary cause of the levee failure on May 5, 2001 and that such failure would have occurred on
<br />May 5, 2001 even if the Bull Seep had been relocated in the approved location. The Division is also of the opinion that
<br />the erosion within [he Bull Seep Slough area resulting from the May 5, 2001 even[ would have been similar in magnitude
<br />regardless of [he location of the relocated Bull Seep.
<br />4. To facilitate the Division's consideration of the possible violation of the statutes and rules noted in Item 1 above, a
<br />letter was sent to MPC requesting additional information relating to the Operator's analysis of [he May 5, 2001 flood and
<br />levee failure. This letter from the Division to MPC is dated November 21, 2001. The Operator's responses to the letter
<br />were provided in separate submittals on December 3, 4, 7 and 10, 2001. In addition, the Division met with consultants to
<br />MPC on December 3, 2001 to discuss the nature and content of the pending submittals. The Division's evaluation of
<br />these submittals and other technical information in the permit file, both pre-dating and post-dating the May 5, 2001 flood
<br />event, and combined with observations made by Division staff during field inspections of the Howe Pit, led to the
<br />conclusions described in item 3 above. The Division does not dispute that [here may have been on-going erosion of the
<br />inboard side of the levee at the location of [he May 5, 2001 failure, and that this erosion was caused by flows in the
<br />mislocated Bull Seep, nor does the Division dispute that there was a hydraulic gradient from the river to the mislocated
<br />Bull Seep that may have led to saturation of the base of the levee and the levee foundation soils. However, the Division
<br />has concluded that the overtopping flows through the pre-existing breach, and no[ these other considerations, were [he
<br />primary cause of [he May 5, 2001 failure and related erosion off the Howe Pit permit area.
<br />5. Upon review of all evidence and information provided by the Operator, the Urban Drainage & Flood Control District,
<br />the Denver Water Board, the Brantner Ditch Company, and Mr. Ken McIntosh the Division concludes that the flood
<br />related damages noted in [he Division's September 14, 2001 RTB letter did not result primarily or directly as a result of
<br />MPC's mislocation of the relocated Bull Seep or the failure to install other associated drainage control structures as
<br />required by the Howe Pit permit. Therefore, we recommend to the Board that [he possible violation of C.R.S. 34-32.5-
<br />116(4)(1) and Rule 3.1.5(3) and C.R,S. 34-32.5-116(4)(h) and Rule 3.1.6(1) noted in the September 14, 2001 RTB letter
<br />be withdrawn from consideration.
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