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predominant valley wind patterns in the vicinity of the licensed facilities. Specifically, the valley experiences diurnal wind patterns such tt,at the primary wind direction during some portions of the day is down valley and at other times is up valley. Since the licensed facilities are located near the valley floor, environmental releases are affected by these wind patterns. Accordingly, the sampling location proximate to the west properly boundary rs located such that it is virtually unaffected by the valley wind patterns and is expected to yield airborne particulate concentrations uninfluenced 6y the licensed facilities. Addendum; The above rationale f.or the use of Lbe sarnpliny (1993) location proximate to the west property boundary is considered valid when viewed in its intended context concerning tt~e establrshment of a site background for tt,e licensed Facilities, however concerns have been voiced about the potential undue influence of non-licenser! facility radiation sources on this location, R review is now in progress to address those concerns. In the interim the sampling location ofEsite on Pine Ridge Road will be used as a background level because it is definitely not affected by either the licensed facilities or non-licensed radiation point sources. IV. Pathways A. External Dose - Direct Gamma Radiation The mineralogy surrounding the licensed facilities makes the determination of a "net" dose for gartuna radiation from l.he licensed facilities difficult. The mineralogy of the opposing valley slopes at the site is quite differet,t. Specifically, the valley side east-northeast of th,~ site is much younger than the valley side nest-northwest of the siCe. The age of the east-northeast side is nn the order of millions of years, while the wr.st-northwest side is about. q to 4.5 billion years old. Needless to say, this leads to a vastly different mineralogy. Tt,e east-northeast ~:ide i:r comprised mostly of sandstones, mudstones, clay and conglomerates, while the west-northwest side is made up o[ metamorphosed gneisses and sc6ists, Geology types sorb as sandstones, mudstones, and clays ate historically associated with higher "background" gamma counts than the metamorpl',used types. This diFference in mineralogy substantially limits the use of a thermoluminescent dosimeter (TLD) Eor background subtraction. To address this problem, Cotter proposed the placement of ten TLDs on the east-northeast vallr.y side f.or a