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"tajor products produced at the Hill between 1930 and 1953 ~. were lead and zinc concentrates utilizing a differential flotation F' ~ process. Of the 700 tons of ore processed per day, approximately 5% was recovered as merchantable product. The remaining 95%, r, primarily ground-up host rock was diverted to the mill waste or ~' tailings circuit at the final stage of the flotation process. The ~. mill tailings stripped of desirable mineral content was then com- biped with mill process wastewater forming a slurry which was pumped ~- to the tailings disposal sites. During the Mayflower Mill operating period, 1930 to 1953, two ~' tailing impoundments, identified as Pond No. 1 and Pond No.2 in Exhibit A (legal descriptions), were constructed employing a gravity launder and decant system. Tailings slurry was pumped from the mill into wooden launders set on a downhill grade, following the disposal site perimeter. The slurry was then discharged from the launders and onto the disposal site perimeter through spigots placed at regular-intervals in the launder. Variation in specific gravities I' of slurry. particles was used in engineering pond construction, with the heaviest particles being deposited first, forming the tailings retention dam or berm. The smaller particles and slurry water were then deposited in sequence toward the pond interior. Decar~t towers were constructed at locations farthest from tailings slurry entry points, and were used to decant clarified water from the pond interior, allowing maintenance of specified berm free board as the impoundment increased in height. By 1953, tailings deposi- tional practices conducted on impoundments Nos. 1 and 2.. had affected approximately 5o acres at the Mayflower Mill site. i• 23.