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~~ ~ <br />~m l~--C S <br />s-l4-a~ <br />s'E„NcEa Seneca Coal Company <br />May 9, 2006 <br />Mr. Daniel Mathews <br />Division of Minerals and Geology <br />101 South 3^~, Suite 301 <br />Grand Junction, CO 81501 <br />(970) 242-5025 <br />RE: Seneca II-W Mine (Permit G1982-057) <br />Report Pursuant to Rule 4.]2(2), Slides and Other Damage <br />Mr. Mathews, <br />Seneca Coal Company (SCC) experienced a slope failure (slide) in the Neck Pit portion of the II-W mute site. This <br />report is in response to Rule 4.12(2) addressing Slides and Other Damage, and includes the date fast observed, a <br />summary of potential factors leading to the slope failure; proposed remediation measures; and a timetable for <br />implementing the xemediation. <br />Initial Discovery: <br />The slide was first observed doting the evening of Apri120~ and the Division was alerted on Apri1215~. The failure <br />occurred prior to April 20~. SCC continues to monitor the slide as weather and access allows. <br />Location: <br />The slide/failure is located in the "Neck Pit" portion of the II-W mine site in TSN, R88W, Section 26. See Figure 1, <br />2006 Neck Pit Slide, which shows the general location of the slide and Photo #1, Apri12150 Observation that shows the <br />physical location. <br />Potenfial Cause: <br />1. The initial cause is believed to be saturated unfrozen ground on a steep slope. The winter of 2005/2006 had mild <br />temperatures and heavy snowfall. <br />2. This area was the site of a spoil failure in January 2001, which slid down over undisturbed ground. The azea was <br />remediated and remained stable until this spring. <br />3. The site had a major snowdrift form at the top of the slope over the course of the winter. See Photo #2, DMG <br />Photo (by Dan Mathews) and Photo #3, Seneca Photo (by Roy Karo). <br />4. Early and rapid snowmelt was believed to be the primary contributing factor. <br />5. A rill formed from dischazge of a culvert under the permanent "Ranch Road" provided the northern boundary of <br />the failure. <br />Extent of Damage: <br />The extent of damage includes the primary slide block and the runout of material at the toe. See Photo #4, Initial Slide <br />Runout (Apri121~t) and Photo #5, Runout Extent (May 2°~. <br />The toe of the slide extends into the aspen along the bottom of the draw covering some topsoil. <br />Only one (1) live aspen was knocked down. <br />Very little mud or debris is present below the initial toe of the slide. See Photo #6 and Photo #7. <br />Seneca Coal Company • P.O. Box 670 • Hayden, Colorado 81639 <br />Telephone (970) 276-3707 • FAX (970) 276-3014 <br />