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SECTION 4.0 GEOLOGY 4.1. INTRODUCTION Federal Sodium Leases C-0118326, C-0119986, C-37474 and C-0118327 properties controlled by Natural Soda, Inc., are located in the north-central portion of the Piceance Creek Basin near the center of saline mineral deposits within the Eocene-aged Green River Formation (Figure 4-1). Leases consist of 8,222.6 acres and are situated between Piceance Creek and Yellow Creek. All of the leases are within T1 S, R98W, 6th Principal Meridian (Rio Blanco County). Meeker, Colorado, lies approximately 41 miles to the northeast. Surface elevation ranges from 6,240 to 6,775 feet; topography is characterized by shallow alluvial valleys and broad soil- covered ridges and mesas. Pinyon, juniper and sagebrush are the dominant plants. The Green River Formation, a thick lacustrine unit deposited in ancient Lake Uinta, contains all of the important oil shale and saline mineral deposits in the Piceance Creek Basin. In the Lease area, the Green River Formation is more than 3,900 feet thick and is overlain by the Uinta Formation (Eocene) and underlain by the Wasatch and Fort Union Formations (Eocene-Paleocene). The Parachute Creek Member of the Green River Formation is the principal resource interval. It averages about 1,746 feet thick in the Lease area and consists primarily of oil shale, marlstone, leached oil shale and saline oil shale (Figure 4-2). Saline minerals in saline oil shale include nahcolite (NaHC03), dawsonite (NaAI(C03)(OH)2) and halite (NaCI). Saline oil shale is located only in the lower part of the Parachute Creek Member in the R-2, L-2, R-3, L-3, R-4, L-4, R-5, and L-5 oil shale stratigraphic zones. This interval, known as the Saline Zone, ranges in thickness from approximately 986 to 1,060 feet thick in the Lease area, and averages approximately 1,011 feet thick. Daub & Associates, Inc. Page 4-1 NSI Mine Plan 2010 Rev. Printed: 7/5/2010 Section 4 Geology