The URL can be used to link to this page

Home My WebLink About1.30 ImpactAnalysis-MineralResourcesEvaluationMINERAL RESOURCE STUDY Respectfully Submitted RMG ENGINEERS GROUP Kelli M. Swick, P.G. Professional Geologist Principal Geotechnical Engineer River Edge Colorado Garfield County, Colorado PREPARED FOR: Carbondale Investments LLC 7999 Hwy 82 Carbondale, CO 81623 JOB NO. 128775 December 3, 2010 Nathan A. Dowden, P.E 2910 Austin Bluffs Parkway Colorado Springs, CO 80918 719.548.0600 Fax 719.548.0223 910 Nottingham Road, Suite N3 P.O. Box 7026, Avon, Colorado 81620 970.949.1970 Fax 970.949.1179 App. P-2 TABLE OF CONTENTS GENERAL PROJECT INFORMATION 3 Project Location 3 Project Description 3 STUDY OVERVIEW 3 SITE EVALUATION TECHNIQUES 4 SITE CONDITIONS 4 Land Use and Zoning 4 Topography 5 Vegetation 5 PREVIOUS STUDIES AND FIELD INVESTIGATION 5 Previous Studies 5 Field Reconnaissance 6 GENERAL GEOLOGY AND SUBSURFACE CONDITIONS 6 General Geology 6 Soil Conditions 7 GROUNDWATER 7 NATURAL RESOURCE DATA - GARFIELD COUNTY 7 RECOVERABLE RESOURCES 7 CONCLUSIONS 8 ADDITIONAL INVESTIGATIONS 8 CLOSING 9 REFERENCES 10 FIGURES Site Vicinity Map 1 Aerial Photograph of Site 2 Aggregate, Sand & Gravel Potential, General 3 Aggregate, Sand & Gravel Potential, Roaring Fork Detail 4 Gas and Oil Well Locations, County Wide 5 ATTACHMENTS Garfield County letter dtd August 18, 2010 RMG Engineers Group -2 App. P-3 GENERAL PROJECT INFORMATION Project Description River Edge Colorado is a proposed residential development comprised of approximately 160 acres lying between the Roaring Fork River and Hwy 82 in Garfield County, Colorado. The property is currently occupied by one single family home and has been previously utilized for agricultural purposes. Although portions of the property are intended to be sold prior to making application to Garfield County for land use approvals required for River Edge Colorado, as of the date preparation of this report, the proposed development lies within a larger 281 -acre parcel owned by Carbondale Investments, LLC. This report addresses the entire 281 -acre parcel. The proposed development will generally consist of installation of underground utilities, overlot grading, construction of residential streets and construction of detached and attached residential structures and community facilities. Project Location The project lies in portions of Sections 7 and 18 Township 7 South, Range 88 West and Sections 1 and 12 Township 7 South, Range 89 West of the 6th Principal Meridian in Garfield County, Colorado. The site is located approximately 5 miles northwest of the Town of Carbondale. The site is bounded on the east by Hwy 82 and on the west by the Roaring Fork River. The approximate location of the site is shown on the Site Vicinity Map, Figure 1 (Ref. 1). An aerial photograph of the site is shown on Figure 2 (Ref.1). STUDY OVERVIEW The purpose of this study is to review available geologic information and existing mapping of commercial mineral resources to develop an opinion regarding the presence, if any, of such resources on the subject property and determine their commercial viability under C.R.S. 34-1-301 et seq. This report has been prepared in support of an application for PUD Plan Review (Rezoning) and Subdivision Review (Preliminary Plan) for the proposed River Edge Colorado development in accordance with the requirements of the Garfield County Unified Land Use Resolution of 2008 (ULUR), as Amended. The Analysis specifically addresses the requirements of Section 5-502.E of the ULUR and C.R.S. 34-1-301 et seq., as requested by Kathy Eastley in a letter dated August 18, 2010 and attached hereto. RMG Engineers Group -3 App. P-4 C.R.S. 34-1-305(1) states in pertinent part that no board of county commissioners shall by zoning, rezoning, granting a variance, or other official action or inaction, permit the use of any area known to contain a commercial mineral deposit in a manner which would interfere with the present or future extraction or such deposit by an extractor. A "Commercial mineral deposit" means a natural mineral deposit of limestone used for construction purposes, coal, sand, gravel, and quarry aggregate, for which extraction by an extractor is or will be commercially feasible and regarding which it can be demonstrated by geologic, mineralogic, or other scientific data that such deposit has significant economic or strategic value to the area, state, or nation. Although requested by Garfield County staff pursuant to C.R.S. 34-1-302(3) the provisions of C.R.S. 34-1-302 are only applicable to populous counties. A "populous county of populous counties of the state" means any county or city and county having a population of sixty-five thousand inhabitants or more according to the latest federal decennial census. As of the rezoning of the property to Residential Suburban in 2008, Garfield County had a population less than 65,000 according to the 2010 census. Although the 2010 census has not been issued to date, current estimates by the State of Colorado (Department of Local Affairs) and U.S. Census Bureau indicate that Garfield County's population is still below the minimum threshold for when these specific statutory provisions apply. SITE EVALUATION TECHNIQUES The information included in this report has been compiled from field reconnaissance, review of available reports of previous studies conducted at the site, geologic research and analysis, a of maps of the site, including natural resource maps compiled and produced by Garfield County, and a review of surficial deposits in Garfield County. SITE CONDITIONS Land Use and Zoning The site is identified as Parcel Number 239318200102 in Unincorporated Garfield County. The site was zoned "Residential/Suburban in 2008 by the Garfield County Board of Commissioners under Resolution 2008-112. As such, Garfield County has already taken action to zone the property for use which would prohibit extraction. Such action was consistent with C.R.S. 34-1-301 et seq. since the RMG Engineers Group -4 App. P-5 provisions of the statute were not applicable. In addition, if the 2010 Census showed that the population of Garfield County exceeds 65,000 persons the zoning would stand as an applicable and allowable use of the property. Topography In general, the site slopes gently to the north and west with a relatively steep escarpment along the westerly boundary dropping down to the river terrace of the Roaring Fork River. Vegetation Most of the site consists of native grasses, weeds, cacti and trees and appears to be denser in the westerly portion near the river terrace. PREVIOUS STUDIES AND FIELD INVESTIGATION Previous Studies Reports of previous geotechnical engineering/geologic investigations for this site were reviewed and are listed below. 1. Geotechnical Engineering Study, Proposed River Edge Colorado PUD and Preliminary Plan Highway 82 and Cattle Creek, Garfield County, Colorado, HP Geotech, Job No. 110 337A, November 10, 2010. 2. U.S. Geological Survey Minerals Yearbook — 2007, Colorado [Advance Release], U.S. Department of the Interior, U.S. Geological Survey, September, 2010 3. Update of Sinkhole Setback Information, Proposed Cattle Creek Crossing Project, Garfield County, Colorado, HP Geotech, Job No. 107 0267, November 30, 2007. 4. Geotechnical Review of Proposed Grading and Erosion Plan along Highway 82, River Bend Development, Garfield County, Colorado, HP Geotech, Job No. 107 0267, August 30, 2007. 5. Preliminary Geotechnical Study, Proposed River Bend Development, Highway 82 and Cattle Creek, Garfield County, Colorado, HP Geotech, Job No. 107 0267, July 17, 2007. 6. Summary of Subsurface Exploration, Proposed River Bend Development, Highway 82 and Cattle Creek, Garfield County, Colorado, HP Geotech, Job No. 107 0267, June 11, 2007. RMG Engineers Group -5 App. P-6 7. Summary of Subsurface Exploration, Proposed Bair Chase Development, Highway 82 and Cattle Creek, Garfield County, Colorado, HP Geotech, Job No. 101 586, December 21, 2001. 8. Phase 1 Geologic Investigation, Sanders Ranch, Garfield County, Colorado, CTL/Thompson, Inc., Job No. GS -1888, July 26, 1996. The findings, analyses and conclusions contained in these reports were considered during the preparation of this report. Field Reconnaissance Site observations were conducted on June 15th and October 12th, 2010 by Nathan Dowden of RMG. Based on our observations, it appears that significant site grading excavation has been previously completed. Visual evaluation of existing site contours and topography compared to the original topographic information presented in the above -referenced reports noted that a considerable amount of the surficial soils appear to have been excavated and either stock -piled on site or transported as "borrow" material elsewhere. GENERAL GEOLOGY AND SUBSURFACE CONDITIONS General Geology Based on the information presented in the HP Geotech reports, the geology of the site is described as Pleistocene (10,000 to 1.8 million year old) and Holocene (less than 10,000 year old) deposits of clays, silts, sands, gravels, cobbles and boulders overlying the Eagle Valley Evaporite bedrock. Review of the Geologic Map of The Cattle Creek Quadrangle (Ref. 4) notes the following surficial deposits mapped on this site: Qa — Stream -channel, flood -plain, and low terrace deposits (Holocene and Late Pleistocene) Qty — Younger terrace alluvium (late Pleistocene) Qtm — Intermediate terrace alluvium (late Pleistocene) Qc — Colluvium (Holocene and late Pleistocene) Qdfy — Younger debris flow deposits (Holocene) Qac — Alluvium and colluvium, undivided (Holocene) The bedrock underlying the surficial soils is noted to be (Ref. 4): IPee — Eagle Valley Evaporite (Middle Pennsylvanian) RMG Engineers Group -6 App. P-7 The surficial deposits are consistent with the information presented on the Surficial Geology Map prepared by Garfield County shown on Fig. 4 (Ref. 5). Soil Conditions As noted in the HP Geotech reports, "...The subsoils encountered throughout the development area typically consist of topsoil and fine-grained soils overlying relatively dense, slightly silty sandy gravel alluvium containing cobbles and boulders. Siltstone /claystone and gypsum bedrock was encountered between 32 and 112 feet below the ground surface...." (HP Geotech, 7/17/07) Based on our field reconnaissance and review of the referenced data, it is our opinion that this is a generally accurate characterization of the site geology and subsurface soil materials. GROUNDWATER Groundwater was reportedly encountered in the soil borings by HP Geotech during their previous field investigations. The groundwater was encountered at depths as shallow as 8 feet and varying to approximately 40 to 80 feet below the ground surface at the time of the previous soil borings. NATURAL RESOURCE DATA - GARFIELD COUNTY As a component of this study, we have reviewed and incorporated mineral resource data and mapping compiled and produced by the Garfield County Building and Planning Department. Specifically, we incorporated pertinent information presented in the Garfield County Comprehensive Plan 2030, adopted November 10, 2010 (Ref. 4). County -wide aggregate, sand and gravel potentials are presented in Figure 3. Figure 4 presents aggregate, sand and gravel potentials in the Roaring Fork river valley. Gas and oil well locations throughout Garfield County are presented in Figure 5. RECOVERABLE RESOURCES Based upon review of the data and maps referenced above, surficial soils throughout the proposed development area have been mapped as clays, silts, sands, gravels, cobbles and RMG Engineers Group -7 App. P-8 boulders. These materials are generally considered suitable for use as interior and exterior backfill, but are considered to be an uneconomical industrial resource due to the current zoning of the property,. developing residential and commercial uses surrounding the property, natural resources values associated with Conservation Easement along Castle Creek and Roaring Fork River, the proximity to and dissection of the site by the Roaring Fork Transit Authority (RFTA) right-of-way which is used as a apart of the Rio Grande recreational trail and preserved by the RFTA and Public Utilities Commission as a rail corridor and the potential presence of groundwater as indicated in the HP Geotech Preliminary Geotechnical Investigations. It is our opinion that more economical sources of sands, gravels and quarry aggregate for industrial/commercial mineral extraction are available elsewhere within Garfield County. As a result, in terms of commercial viability, these deposits have limited potential viability when considered within the context of Garfield County's overall resources and development. The on site deposit does not constitute a deposit that has significant economic or strategic value to the area, state, or nation. The data does not indicate that limestone or coal are located on the property. CONCLUSIONS Based on our field observations, review of the referenced geotechnical/geologic investigations and other data noted herein, it is our opinion that development of the property for residential purposes will not prohibitively impact Commercial Mineral Deposit resources in Garfield County. While most of the surficial materials at this site appear to be suitable for use as grading fill, utility trench backfill and roadway subgrade materials, their commercial viability is significantly impacted by a variety of issues including existing zoning, surrounding development, conservation values, groundwater, and the location and preservation of a rail corridor. ADDITIONAL INVESTIGATIONS The findings, conclusions and opinions presented in this report are based upon the provided information, referenced documents, field observations and our experience. The suitability of the specific soil and rock materials for any intended purpose must be evaluated based upon field investigations and testing as deemed necessary by the responsible entity. RMG Engineers Group -8 App. P-9 CLOSING This report has been prepared for Carbondale Investments, LLC in accordance with generally accepted geotechnical engineering and engineering geology practices. The conclusions and recommendations in this report are based in part upon data obtained from review of available topographic and geologic maps, review of available reports of previous studies conducted in the site vicinity, a site reconnaissance, and research of available published information. Our professional services were performed using that degree of care and skill ordinarily exercised, under similar circumstances, by geotechnical engineers and engineering geologists practicing in this or similar localities. RMG does not warrant the work of regulatory agencies or other third parties supplying information which may have been used during the preparation of this report. No warranty, express or implied, is made by the preparation of this report. RMG Engineers Group -9 App. P-10 REFERENCES 1. MSN/Google Earth`, 2010, as of Nov. 12, 2010. 2. Garfield County 2008 Unified Land Use Resolution, Updated Through July 2010. 3. Geologic Map of the Cattle Creek Quadrangle, Garfield County, Colorado by R.M. Kirkham, et al, 1996, Colorado Geologic Survey. 4. Garfield County Comprehensive Plan 2030, adopted November 10, 2010, Garfield County Planning Commission, Garfield County, Colorado. 5. Geotechnical Engineering Study Proposed River Edge Colorado PUD and Preliminary Plan Highway 82 and Cattle Creek, Garfield County, Colorado, HP Geotech, Job No. 110 337A, November 10, 2010. 6. U.S. Geological Survey Minerals Yearbook— 2007, Colorado [Advance Release]. 7. Update of Sinkhole Setback Information, Proposed Cattle Creek Crossing Project, Garfield County, Colorado, HP Geotech, Job No. 107 0267, November 30, 2007. 8. Geotechnical Review of Proposed Grading and Erosion Plan along Highway 82, River Bend Development, Garfield County, Colorado, HP Geotech, Job No. 107 0267, August 30, 2007. 9. Preliminary Geotechnical Study, Proposed River Bend Development, Highway 82 and Cattle Creek, Garfield County, Colorado, HP Geotech, Job No. 107 0267, July 17, 2007. 10. Summary of Subsurface Exploration, Proposed River Bend Development, Highway 82 and Cattle Creek, Garfield County, Colorado, HP Geotech, Job No. 107 0267, June 11, 2007. 11. Summary of Subsurface Exploration, Proposed Bair Chase Development, Highway 82 and Cattle Creek, Garfield County, Colorado, HP Geotech, Job No. 101 586, December 21, 2001. 12. Phase 1 Geologic Investigation, Sanders Ranch, Garfield County, Colorado, CTL/Thompson, Inc., Job No. GS -1888, July 26, 1996. RMG Engineers Group - 10 - App. P-11 FIGURES RMG Engineers Group -11- App. P-12 r Glenwood 5p i nq s NOT TO SCALE Colorado Springs: (Main Office) 2910 Austin Bluffs Parkway Colo. Spgs., CO 80918 Voice (719) 548-0600 Fax (719)548-0223 Summit County: 202 Main Street#22 Post Office Box 4038 Frisco, Colorado 80443 (970) 668-4530 Fx (970) 668-4589 Rig Qy APPROXI V ATE SITE LOCATIO\ Carbondale Structural • Geotechnical ENGINEERS El Jebel REFERENCE: MSN MAPS 2010 SITE VICINITY MAP RIVER EDGE COLORADO GARFIELD COUNTY, COLORADO L. gais.alt JOB. No. 128775 FIQ. No. 1 DATE App'11A2/10 r NOT TO SCALE Colorado Springs: (Main Office) 2910 Austin Bluffs Parkway Colo. Spgs., CO 80918 Voice (719) 548-0600 Fax (719)548-0223 Summit County: 202 Main Street#22 Post Office Box 4038 Frisco, Colorado 80443 (970) 668-4530 Fx (970) 668-4589 Structural • Geotechnical ENGINEERS REFERENCE: MSN MAPS 2010 JOB. No. 128775 FP. No. 2 DATE AP P11/42/10 AERIAL PHOTOGRAPH OF SITE RIVER EDGE COLORADO GARFIELD, COLORADO 71 CA) 0> mO) m Qo 300 rt G 0 z m :1vuiwans of/ZL/L l :31va A8 03N133H3 ij AGGREGATE, SAND & GRAVEL POTENTIAL RIVER EDGE COLORADO GARFIELD COUNTY, COLORADO Colorado Springs: (Main Office) 2910 Austin Bluffs Parkway Colo. Spgs., CO 80918 Voice (719) 548-0600 Fax (719) 548-0223 Structural • Geotechnical Summit County: 202 Main Street #22 Post Office Box 4038 Frisco, Colorado 80443 (970) 668-4530 Fx (970) 668-4589 ENGINEERS App. P-15 07 c m m0 (n D ,-Dj Qo Z G) G)_ -n 0 m 0 z 1Hll warts :Aa a3NO3H0 Aa NMVLI0 0 m m oI/ I/ll 3110 ON :2l33NIJN3 AGGREGATE SAND & GRAVEL POTENTIAL Colorado Springs: (Main Office) 2910 Austin Bluffs Parkway Colo. Spgs., CO 80918 Voice (719) 548-0600 Fax (719) 548-0223 Structural • Geotechnical RIVER EDGE COLORADO GARFIELD COUNTY, COLORADO Summit County: 202 Main Street #22 Post Office Box 4038 Frisco, Colorado 80443 (970) 668-4530 Fx (970) 668-4589 MG ENGINEERS App. P-16 5 m m 0O O 0O X� z>O -< O ow m m O z lVlll J flS :AS O3)1O3HO 0 z co GAS AND OIL 75 m 014Z L/ l l :31HO ON :2i33N1`JN3 WELL LOCATIONS Colorado Springs: (Main Office) 2910 Austin Bluffs Parkway Colo. Spgs., CO 80918 Voice (719) 548-0600 Fax (719) 548-0223 Structural • Geotechnical RIVER EDGE COLORADO GARFIELD COUNTY, COLORADO Summit County: 202 Main Street#22 Post Office Box 4038 Frisco, Colorado 80443 (970) 668-4530 Fx (970) 668-4589 App. P-17 ATTACHMENTS RMG Engineers Group - 12 - App. P-18 BUILDING & PLANNING DEPARTMENT August 18, 2010 Rockwood Shepard, Project Executive Carbondale Investments, LLC 7999 Highway 82 Glenwood Springs, CO 81601 rshepard@westpacinv.com Re: River Edge Development Application Dear Rocky, As you may be aware, the Garfield County Planning Commission is in the process of considering an updated Comprehensive Plan for Garfield County. During this process, there has been renewed interest in the requirements of Article 34 of the Colorado Revised Statutes, particularly the provisions relating to preservation of commercial mineral deposits, § 34-1-301, et seq., C.R.S. (2009). Under the provisions of § 34-1-305(1), C.R.S., the board of county commissioners may not permit the use of any area known to contain a commercial mineral deposit in a manner that would interfere with present or future extraction of such deposit by an extractor. Thus, we are requesting that in any future land use application you address the issue of the existence of commercial mineral deposits on any property for which development is proposed. Sincerely, Kathy Eastley, AICP CC: Don Deford, County Attorney Deb Quinn, Assistant County Attorney Fred Jarman, Director of Building and Planning 108 Eighth Street, Suite 401 • Glenwood Springs, CO 81601 (970) 945-8212 • (970) 285-7972 • Fax: (970) 384-3470 App. P-19