2019-10-18_REPORT - M1978208

• Permit No: M1978208
• IBM Index Class Name: REPORT
• Doc Date: 10/18/2019
• Doc Name Note: Unofficial Report/Maps
• Doc Name: Annual Fee/Report/Map
• From: Elk Creek Sand & Gravel, LLC
• To: DRMS
• Email Name: ECS
• Email Name: MAC
• Media Type: D
• Archive: No

T
DRMS SUPPLEMENTAL REPORT:Concerns in re COMPLIANCE RE BENCHING within HIGHWALL
12/6/18 MLRB 1978-208 Shaffers Crossing
consider a waiver under the Rules allowing for a minor modification under a technical reviiso
supporting a more vertical highwall.
Operator submits as evidence for the above as follows:
a) Operator provides Division Staff by electronic submittal on or proximal to 4/13/18 surface
topographic detailing the countours of a drone flyover on or around September 2017. No
changes to the finished highwall have taken place between Septmeber 2017 and May 2018,for
the section of the highwall in question. Such fivover by Alnhapixel Services Inc_, Evergreem CO;
was converted to surface topgraphic contours on a 2'-0" interval I a CAD format,however,
asince Alphapixel is not certified land surveyor in accordance with State regulations,the work
product could not be verified and was indeed generated at 8 degrees fromvertical in the
oblique.Given the potential for discrepancy and the lack of resolujtion on the final work product
this was rejected by Division staff. Operator also requested an additional extension of 60 days'
time to pursue a reasonable remedy in the alternate. (EXHIBITS 1, 2,3)
b) Operator pursued a second drone survey with resulting topographic survey through Falcon
Surveying, Inc., Principal Jeff McKenna.The Falcon crew was mobilized in June 2018 and had
mixed success in obtaining data given a wind event interrupting data collection at the site. Of
the three drones employed,only one had a reasonable level of success. Following this the crew
extrapolated data and developed a full size CAD rendering of the property overlain by a certified
survey of the property and anchored on a state registered memorial within the CDOT ROW at
the NW corner of the property.The Data was provided to the Operator in July 2018.This data
employed a 5'-0"contour interval.The Operator provided the results of the survey to the State
Inspector at the Division thereafter. (EXHIBIT 4)
c) Operator submits to the State Inspector as evidence that it is compliance the following
• 2018 TOPO Certified Survey on 5'4' intervals(as detailed EXHIBIT 4) (Falcon Surveying
2018)—indicating 5 sets of benches (variable) in compliance with the plan as approved by
State and in accordance twitch the Rules,given those sections where mining is complete
• Geotechnical and slope stability report and GEOLOGIC REPORT(2006) (prepared by Alan
Howard, PE., Brierley and Associates) (EXHIBITS)—indicates through a Mohs Coulomb
curve and phi values that the slopes as indicated fall within the recommended design limits
(restrictions)as provided for in the report and are thus not subject to potential overturning
or toppling.
• Geologic Report(Fox and Assis 1978) (EXHIBIT 6)—indicates values within the materials
more specifically where those values are defined by the more exposed westerly weathered
colluvium and other material characterized by a more decomposed feature, presenting
more potential for failure and toppling. Given that this layer is given as between 5'-0"and
10'-0"think generally speaking in those areas where it existed (along the Elk Creek side of
the properties)this material has thus been mined out and no longer exist and therefore,by
definition,cannot be considered to form part of the rock mass in question
Operators submits various annual inspections of the
Highwall ((1)2018 ANNUAL HIGHWALL INSPECTION AND SLOPE STABILITY ANALYSIS)
(EXHIBIT 7)and