2021-05-05_REVISION - M1983033 (3)

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Walstrum Spur Amendment, Exhibit D—Mining Plan May 2021 Mining of the affected area of the 8-acre Parcel B2 will occur in conjunction with mining of the west side of the Existing Quarry. A portion of this parcel, depicted on Exhibit C-3, will remain undisturbed as a screening buffer as viewed from Highway 6. The overall timeline for mining the Spur Amendment is 30 to 50 years. Existing Quarry Timetable Mining in the Existing Quarry will occur concurrently with mining in the Spur Amendment area. The reason for mining both areas at the same time is that the resource quality in the two areas is different. Material in the Spur Amendment is of a higher quality and will be blended with material from the Existing Quarry. In this manner, mining in both areas will occur at roughly half the rate that would occur if only one area was being mined. In general, the Existing Quarry will be mined in a counterclockwise manner. Current mining will continue with the existing benches on the east side, then the north side, then the west side. The overall timeline for mining of the remaining areas of the Existing Quarry is 20 to 50 years. 3.6 Nature of Deposit (1) A map (in Exhibit C - Pre-Mining and Mining Plan Maps(s) of Affected Lands, Subsection 6.4.3) may be used along with a narrative to present the following information: (i) nature, depth and thickness of the ore body or deposit to be mined and the thickness and type of overburden to be removed(may be marked "CONFIDENTIAL,"pursuant to Paragraph 1.3(3)); (ii) nature of the stratum immediately beneath the material to be mined in sedimentary deposits. Exhibit C-3 shows the Affected Lands. In the Spur Amendment area, there is typically less than 1 foot of topsoil overlaying 4 feet of silty sand colluvium followed by 5 feet of weather gneiss before hitting competent bedrock at approximately 10 feet. The majority of the disturbed area has a soil classification of Cathedral-Rock outcrop complex. This soil type typically has only a 10-to 20-inch depth to lithic bedrock and no soil over bedrock in the rock outcrop areas which cover a substantial portion of the disturbed area (see Exhibit I Soils Information). Topsoil is relatively absent from this operation as confirmed by test pits dug on-site in 2020 (see Geotechnical Stability Exhibit). The bedrock is a metamorphic rock including layers of Biotite Gneiss, Feldspar Gneiss, Hornblende Gneiss, and Interbedded Gneiss. The average thickness of the deposit is more than 600 feet. The Geotechnical Stability Exhibit included in this application presents a summary of the geologic investigation describing the nature and depth of the aggregate material and overburden in more detail. 3.7 Commodities to be Mined 6.4.4(g) Identify the primary and secondary commodities to be mined/extracted and describe the intended use; The primary products produced from the Existing Quarry are and will continue to be aggregates for use as construction materials. No secondary commodities will be extracted. 3.8 Intended Use of Incidental Products 6.4.4(h) name and describe the intended use of all expected incidental products to be mined/extracted by the proposed operation The overburden will be manufactured into road base product. The gneiss rock will be manufactured into the aggregate products. No other incidental products will be produced. 3.9 Explosives 6.4.4(i) Specify if explosives will be used in conjunction with the mining (or reclamation). In consultation with the Office, the Applicant must demonstrate, pursuant to Subsection 6.5(4), Geotechnical Stability Exhibit, that offsite areas will not be adversely affected by blasting. DTETRA TECH P a g e 6 19