2024-12-16_REVISION - M1977410 (26)

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Page 5 of 18 quality standards for drinking water found in Rule 41 as the mine is not located in a classified area found in Rule 42. Based on site-specific conditions, regional to local studies of surface and groundwater quality, baseline sampling for this plan, and the lack of observations of acid-rock drainage or seepage over the 150-year history of the Caribou and Grand Island mining districts, GIR does not believe that operations at the Cross Gold Mine have the potential to impact water quantity, or groundwater quality beyond standards imposed by the WQCC. The site-wide hydrogeologic characterization is ongoing at the property. The current understanding is sufficient to support development of a groundwater monitoring plan as it covers areas and activities currently permitted at the Cross Gold Mine. GIR is expanding the characterization by: x collecting existing water well and in-mine water level data using equipment downloaded at regular intervals, x testing aquifer properties at water wells and core holes, x evaluating in-stream flows and groundwater surface water interaction as part of a separate investigation to support water court determinations, and, x an engineering evaluation of in-mine groundwater flows to be expected under different underground development and mining scenarios. 2 CLIMATE AND PHYSIOGRAPHY Colorado is divided into two major geographical regions, the Eastern Plains, and the Rocky Mountains. The facility is located along the eastern flank of the Front Range of the Southern Rocky Mountains at an elevation of 9,000 to 10,500 feet above sea level. The facility is located in sub-alpine terrain upslope of the Town of Nederland, Colorado, in the Coon Track Creek sub-basin of Middle Boulder Creek basin. The topography of the mine site is fairly gentle however many of the surrounding mountains are steep and rugged. Similarly, many of the nearby drainages are deeply incised. The hills and ridges are covered mainly by residual soil and glacial till, which is drained by slightly to deeply incised creeks. Rock outcrop is generally rare, perhaps 5% or less over the entire property. The climate of this sub-alpine zone is cool, with summer highs reaching 75 °F only on the warmest days. Frost may occur any day of the year. High winds are common throughout the year, with potential gusts up to 130 miles per hour. Snow is a common occurrence for most of the year, except for July and August. Average minimum winter temperatures are 20 to 30 °F and maximum summer temperatures are 65 to 75 °F. Annual precipitation averages 18 inches of rain and 139 inches of snow. April and May have the most precipitation; summers are generally dry with brief but intense thunderstorms associated with the Southwestern US Monsoon season.