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EXHIBIT D -MINING PLAN ,. _ . ~~ Unless specifically discussed in the following text, the mining methods described in the original permit application and approved under Colorado Mined Land Reclamation Board (CMLRB) Permit #M-77-526 for the existing Worthing Pit will remain unchanged. Under this amendment, additional sand and gravel will be dry mined by dewatering at the Worthing Pit, the post-mining land use for Worthing Pit will be modified to increase the remaining lake surface area, and an additional 50.3-acre Expansion Area will be added to the mine permit area as illustrated in Exhibits B-1, C-1, C-2, and C-3. The Expansion Areas will be dewatered and dry mined. The Expansion Area will be mined in two phases. First, a 21-acre area immediately adjacent to the existing south permit boundary and designated as "Expansion Area North" will be mined (Years 0-3). Afrer Expansion Area North is mined out, a 29.3-acre area south of Expansion Area North and designated as "Expansion Area South" will be mined. General Geology The Expansion Areas consists of Quaternary age sand and gravel deposits similar to those being mined in the adjacent Worthing Pit. Deposited by the South Platte River and its tributaries, these aggregates are of the Post-Piney Creek Alluvium and form a surface cover on the Louviers Alluvium. Louviers Alluvium overlies the sandstones and shales of the Cretaceous Denver- Arapahoe Formation, the oldest unit in the Expansion Areas. This is the bedrock formation for the Expansion Areas and is composed of very thin to thick-bedded clayey, silty sandstone and sandy siltstone with interbedded carbonaceous silty shales and claystone. The carbonaceous shale is light to medium dark grey and locally contains plant fragments with few poorly preserved leaf imprints. The well-graded sand and gravel in this formation consist of approximately 65 percent quartz, 15 percent feldspar, and 20 percent rock fragments made up of granite, argillite, very weathered metamorphics, chert and claystone. Overburden on the Expansion Areas consists of unconsolidated materials of an A soil horizon, ranging from 0 to 1.0 feet. Where available, the topsoil will be removed and stockpiled for later distribution during reclamation. No other overburden such as shale or subsoil unconsolidated material is present above the tnineable area, and no blasting is required. Existing Conditions and Technical Revisions The existing permit area at Worthing Pit is 110.6 acres. Over 25 years of mining activities at the Worthing Pit have produced three pit lakes, totaling approximately 57 acres as shown on Exhibit G-2. Pit Lake I is 44.7 acres, Pit Lake 2 is 9.5 acres and Pit Lake 3 is 3-acres. Per Technical Revision (TR 9/84), dated September 7, 1984, a total lake surface area of approximately 27.5 acres is to remain with no backfilling at mine closure. TR-2, dated November 28, 2000, authorized dewatering and then dry mining of the pit lakes at Worthing Pit. To date, Worthing Pit has not yet implemented dewatering for dry mining. Per the TR-2 request submittals, dated November 1, 2000, no surface water wells would be impacted by dewatering of Worthing Pit. In 2000 there were three surface wells within 600 feet of Worthing Pit; however, these wells have now been plugged and abandoned. The pre-1981 iota] exposed lake surface area at Worthing Pit was approximately 24 acres. Expansion Area North has apre-1981 pit lake of approximately 3.6 acres. The pre-1981 total exposed lake surface area for the amended permit area is approximately 28 acres. 1898-Frei 112 Exhibits_(4.20.05).doc D-1