GENERAL47519 - Laserfiche WebLink

Home Browse Search

Geoloev The geology discussion centered on the fact that the Collom project area is a closed basin that is surrounded by synclines. No faulting has been observed to date. It is the Divisions understanding that the current mine plan does not propose any mining below the KM-marker bed. This bed has a permeability of less than 10"13. By staying above the KM, Colowyo is not anticipating any effects to the groundwater. The Division has previously approved the overburden sampling and chazacterization plan from June 2004. The proposed mine plan, at this time, has the initial box-cut being opened in the south azea and mining down-dip. This azea has less overburden and would create less excess spoil (-50 million cubic yards vs. 150 million cubic yards). The excess spoil valley fill would be in one of the drainages near the box-cut, possibly the upper east fork of Collom Gulch. The project is not expected to mine through Collom Gulch. Groundwater Colowyo believes at this time that the Collom project will result in a dry pit. There aze some perched aquifers in the interburden but they are limited in areal extent. Based on the extensive drilling program Colowyo has undertaken, there appeazs to be no groundwater correlation from hole to hole. The boundaries for the study azea are the Trout Creek Sandstone outcrop on the north, east and west, and the Dansforth Hills anticline crest on the south. Colowyo has been collecting baseline groundwater samples in 25 bedrock and 9 alluvial wells. Surface Water Surface water includes ephemeral and intermittent streams upstream from the Collom project azea. There are perennial streams downstream of the project area. Based on the area being a closed basin, the main hydrologic concern for the proposed Collom mine would be the surface water. All of the water that would enter and, subsequently, leave the pit, would be discharged into perennial streams. Some of these streams aze used for irrigation downstream of the proposed Collom project, including Milk Creek and Morgan Creek. Colowyo is currently collecting baseline surface water data. Soils The soils investigation and mapping scope of work was closely coordinated between Maxim and the Division, as discussed in the 28 August 2005 submittal from Maxim and the 8 September 2005 response from the Division. The Division believes that the current scope will provide a very good product with regards to the soils baseline data. It was mentioned at the meeting that more than 400 test pits were dug and that topsoil depths ranged from none/unsalvageable to four feet. Some of the azeas out of the proposed pit azeas were said to have "very deep" soils.