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<br />aquifer in this area. Many of the surrounding landowners have irrigation wells into this <br />unconfined aquifer, with depths going from 4 or 5 feet below the surface to about 25 to <br />35 feet below ground level, depending on location. There is concern that during <br />dewatering for mining activity, the groundwater level will be depressed, creating <br />damages to the neighbors. Also, it is believed that at some later time, a future owner of <br />the site may intend to line the reclaimed pit to create water storage. This may create a <br />bulge and shadow effect producing damages both upstream and downstream of the site. <br />Computer modeling has borne out this potential as a real one. <br />Stakeholders, including Lafarge, Larimer County, and a Neighborhood Issues Group, <br />' formed at Lafarge's request and consisting of a number of the surrounding land owners <br />acting as liaisons to the neighborhood, generally agree that a well monitoring program is <br />necessary to insure that adverse affects to the groundwater levels created by mining <br />activities are properly mitigated. This protocol is intended to provide answers for some <br />parts of that approach. <br /> 1.3 Information Goals <br /> As alluded to earlier, it may be useful to begin with some description of what a <br />' monitoring protocol can realistically produce. It is well known that groundwater levels <br />fluctuate for a variety of reasons, many having nothing to do with mining activities. A <br /> dry year may drop groundwater levels. Water running in irrigation ditches (several are <br /> located in the area) may raise the water level in their vicinity. River flow, in this case <br />heavily controlled by snow pack depths in the high mountains and upstream irrigation <br /> diversions, will affect groundwater levels in this area. In other words, a variety of causes, <br /> many hard to measure or quantify, affect existing groundwater conditions. These natural <br />conditions may generally be described as seasonal, but may also have long term effects <br /> carrying over from season to season and year to year. A monitoring program cannot <br /> discern whether changes in groundwater levels (the variable being measured) have <br /> occurred due to a particular cause. Awell-designed monitoring system will, however, <br /> determine within a certain confidence level, what the condition was before mining began <br />' and what it is like after mining has commenced, and whether the difference is significant. <br /> There are several layers of information needs pertaining to this proposed mining <br /> operation. Putting aside the question of cause for a moment, groundwater levels are of <br /> concern to several stakeholders. Obviously, Lafarge is interested in an accurate estimate <br /> of any impacts its operation may behaving. Neighbors are concerned that they are able <br /> to irrigate from their existing wells at the same rate and quality as they had prior to the <br /> start of mining. They aze concerned about loss of sub-imgation for lawn cover, trees and <br /> pasture grasses. Neighbors upstream of the site are concerned that if a liner is used, the <br /> bulge effect could raise groundwater levels high enough to cause harm to structures and <br /> even flood leach fields causing public health problems. Neighbors also have concerns <br /> that open ponds that provide wildlife habitat and amenity will be affected. <br />' From a regulatory standpoint, Larimer County has expressed concern inasmuch as the <br /> neighbors' interests are protected. The underlying legal authority for mining in the state <br /> <br />1 2 <br />