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MEMORANDUM At Adrian Brown To: Gabe Racz, Vranesh and Raisch, LLP Gene Riordan, Vranesh and Raisch, LLP CC: Margaret Burt, Newmont Mining Inc. From: Adrian Brown, P.E., Adrian Brown Consultants, Inc. Re: Additional Information Request—Natural Water Level Date: August 11, 2016 Groundwater Flow in the Cripple Creek Diatreme The groundwater flow regime in the Cripple Creek diatreme is dominated by geology.The diatreme is located on a hill, and receives precipitation of approximately 20 inches per year(ABC, 2015).The volcanic rock in the diatreme is of moderate to low permeability, and in general approximately 6 inches per year of that incident precipitation infiltrates to the diatreme,with the balance evapotranspiring (ABC, 2015). However, small surface runoff occurs in some areas of the diatreme during high precipitation or thaw events, which results in a modest reduction in the amount of infiltration and evapotranspiration within the diatreme. The diatremal rock is surrounded by low permeability Precambrian gneiss, schist,granite, and granodiorite,which serves as a container for the groundwater in the diatreme (Lindgren and Ransome, 1906). The geology of the Cripple Creek mining district is shown in Plate 1. The extent of the diatreme is presented in Plate 2. The diatreme comprises three steep-sided eruptive centers, at the north,west, and south, where upwelling volcanic matter was ejected. In addition,there is a gently thinning volcanic rockmass to the east,where volcanic material flowed after being discharged from the volcanic centers.This overflow apron is generally devoid of economic gold. Historic (Pre-Mining) Groundwater Elevation The elevations of groundwater in the Cripple Creek mining district prior to the inception of mining were obtained in the pioneering study of the (then) 277 underground mines in the district performed by Lindgren and Ransome(1906).The district and the mines they inspected are shown in Plate 3. During the study of the mines Lindgren and Ransome carefully recorded the hydrogeology of the "wet" mines in the district, collecting information relating to the water level prior to and during operation,which is reported in detail in Chapter XII—Underground Water.This information is summarized on Plate 4,taken from Pages 240- 241 of Lindgren and Ransome (1906). In addition, Lindgren and Ransome provide a diagram showing this information,which is presented in Plate 5 of this memorandum.At the base of Plate 5 is a summary of the name, location, pre-mining water elevation estimate, and first water encountered. The pre-mining water level data that is presented in Plate 5 is plotted on a map of the diatreme in Plate 6.The following observations are made: Page 1 Adrian Brown Consultants, Inc. 130 W.4ch Ave., Denver CO 80223 303-698-9080 www.abch2o.com