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c c ; Mr. J .A . Brown Mr. D.H. Cochran Mr. I K E , Edlund Mr. J .T . L ing Mi1, H.S. Parkinson May 15, 1962 R,C. C o llin s MINNESOTA MINING & MANUFACTURING COMPANY GEOLOGY DEPARTMENT Report No. 6l-22 Supplement S u b je c t: Introduction = R eference: C onclusions: Pond s e a la n t study We have been r e q u e s te d by th e W ater and S a n ita r y E ngineering Department to run a couple of a d d itio n a l f i l t r a t i o n columns in reg ard to t h e i r E ngineering s tu d y f o r th e Woodbury dump s i t e . L ast December v ario u s s e a la n t m a te ria ls were stu d ie d and i t was found t h a t a 10# B e n to n itic c la y mixed w ith th e top one foot of th e sandy g la c ia l d r if t would g iv e an e f f e c tiv e pond s e a l f o r p la in w ater. T h is s tu d y was made to e v a lu a te th e wet s c ra p ' c u r r e n tly b e in g dumped a t th e Woodbury s i t e . The 'wet w aste" c o n ta in s a h ig h p e rc en ta g e o f v o la tile s p rin c ip a lly acetone and a very l i t t l e w ater. This stu d y was conducted to d e te rm in e i f th e wet s c ra p would r e a c t w ith th e b e n to n itic c la y and g iv e an effectiv e seal. Geology R eport 61-22, December 18, 1962 Geology R eport 62-9.. M archS?, 1962 , Wet S c r a p ' s u p p lie d by J . L . , May 2. 1962 A. The s ta n d a r d f i l t r a t i o n column c o n s i s t i n g o f a 33 mm. d ia m e te r g la s s tu b e ( s e e d raw in g a tta c h e d to r e p o r t 62- 9 ) was ch arg ed w ith one f o o t o f sandy g la c ia l d r i f t m a te ria l and f i l l e d w ith wet scrap to head h e ig h t o f th r e e f e e t . I t was d e te rm in e d t h a t th e wet sc ra p would p e rc o la te a t a r a te in excess of 250 g a llo n s p e r day p e r sq u are fo o t o f s i t e a re a . B. The s ta n d a rd f i l t r a t i o n column was charged w ith a one fo o t m ixture of 10# B en to n itic clay and th e sandy g la c ia l d r i f t and s lig h tly packed. The f i r s t 72 hours w ith a wet s c ra p head o f th re e f e e t, th e m a te r ia l seep ed o n ly one in c h . The column was th e n extended and a 7 f o o t wet s c r a p head was m ain ta in e d fo r fiv e d ay s. The wet scrap only seeped an a d d itio n a l 3/4ths of an Inch in th e sand-clay m ixture. For th e l a s t 24 hours of th e 5-day p e rio d , no v is u a l in c r e a s e was n o tic e d . C. A s e r i e s o f sam ple t e s t s w ere made u s in g A cetone and B e n to n itic c la y and i t was found t h a t th e r e wan a s lig h t reactio n or sw elling but not nearly to the e x te n t as a w ater and B e n to n itic clay,. 3MA00335853 Trial Exhibit 491 3M MN00000380 G eology R e p o rt Mo, 6 1 -2 2 S u p p lem en t May 15, 1962 Recom m endations: Prom th e above t e a t s . I t i s co n clu d ed t h a t a tem p o rary s o lu tio n in th e v e t w aste s c ra p problem can be made by s e a lin g th e pond o r tre n c h e s w ith a 10# m ixture of B e n to n itic c lay and sand. The c o n s tr u c tio n o f th e s e p i t s o r tre n c h e s would be o f th e u tm o st im portance and in t h e i r o p e ra tio n so as n o t to b re a k down th e 3 id e s of the tre n c h e s, i t is suggested th a t b efo re th e tren ch es a re a c tu a lly put in to o p e ra tio n that, th ey be sprayed w ith w ater to re a ct the B en to n itic clay. I t s t i l l is th e consensus o f th e Geology D epartm ent in re g a rd to safeguarding th e underground w ater supply of th e area , r th a t th e company s e r io u s ly c o n sid e r th e i n s t a l l a t i o n o f an in c in e r a to r o r o th e r means whereby th is wet w aste m a te ria l w ill n o t have an o p p o r tu n ity to seep in to the s o il. RCC/eb 3MA00335854 3M MN00000381