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<br />1,
<br />RATIONALE FORW[THDRAWAL tA~~~lC1~
<br />(Howe Pit, Permit M-78-052, 12/12/01) ~'( ~ r
<br />l . 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 [o [he 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 [hat approved in the Mined Land Reclamation Permit. The letter further cited MPC's failure to properly install other
<br />associated drainage control structures as required by the permit. In its RTB letter the Division described a possible
<br />violation of C.R.S. 34-32.5-1 16(4)(1) and Rule 3.1.5(3) for failure to protect areas outside the 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 to the prevailing
<br />hydrologic balance of the affected land and of the surrounding area and to [he 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 [he October 17, 2001 meeting the Mined Land Reclamation Board continued the scheduled hearing a[ the request of
<br />[he Division. The basis for [he continuance was that the Division needed additional time [o review technical information
<br />submitted by [he 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 34-32.5-116(1), 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 l5, 2001 demonstrates that there was a
<br />pre-existing breach in the levee (this levee is referred to by the Operator as a repaired riverbank - not 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 the Bul] Seep Slough area resulting from the May 5, 2001 event would have been similar in magnitude
<br />regardless of the 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 [o MPC requesting itiona fo ion relating to the Operator's analysis of the May 5, 2001 flood and
<br />le at ure. his le[ from the iv~onso ~ is da d November 21, 2001. The Operator's responses to the letter
<br />ere provi~ed ir~eparat ubmi als o~ecember~!4, 7 d 10, 2001. In addition, the Division met with consultants to
<br />PC on Beee°vrnber-3•, 2001 o dis s the nature and come t of the pending submittals. The Division's evaluation of
<br />th subminals and other t chnical in in t file, both pre-dating and post-dating the May 5, 2001 flood
<br />even[, mbined wit bservations 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 [hat there may have been on-going erosion of [he
<br />inboard side of the levee at the location of the 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 not these other considerations, were the
<br />primary cause of the May 5, 2001 failure and related erosion off [he 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 the 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 the 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 ]4, 2001 RTB letter
<br />be withdrawn from consideration.
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