Document jgykpM0nnnj6K4bGb35J9ko9k

ccs Mr. h.c. uollins to. M.C. Goldsmith. r. toller Proposed Gump tote July lj, 1960 TO 1 Mti. HAaS WETSEL - SMGXKGSRiNO C3PX, - 207-1 PROMl {jQHfiA. BROwT)- GEOLOGY DEPT. - Z7-c Reference: Geology Dept. Report #60-10 This Is to acknowledge your request of July 3th concerning the geology and aubaurfsee drainage of a new proposed dump site. The proposed 2jj.O acre site is located in the southern one-half of aection 35# T27N R21W, or approximately one mile north of Cottage Grove in Woodbury U S , Washington County. This area is principally agricultural with the lsnd parcels averaging approximately 100 acrea each. A faw commuters have taken over acme of the farms as well aa building suburban homes on a few of the small nearby lakes. As ws understand it, this property has been secured by a 30-day earnest money contract between oarl Ryan (of Terminal Warehouse) and tha present land owner, a to*. Dahm. Mr. Ryan la holding the papers on this property in his own name to minimise publicity. It is fur ther understood that Terminal Warehouse Co. will secure written per mission from the Woodbury TWS Committee for this proposed lend usage. Terminal warehouse also will engage people for the teat drilling* We also understand that this proposed dump site will or may be used by all plants in the St. Paul area. There will be wet acid and phenol waste > wall as dry waste material. At this time there are no plans to construct a drainage pond or to provide burning facilities. The wet waste material will be dumped in long trenches and allowed to seepInto the ground and aa soon as one ares becomes saturated, It will be coveredover and another trench dug.ibe dry waste material will be buried. Geologically speaking, the general area has a typical glacial ground moraine topography with a maximum relief of about 100 feet. The prin cipal bed rock formations underlying thla area are the St. Peter sand stone intermittently covered with rlattvllle limestone. These bedrock formations are overlain with 30 to 80 feet of glacial drift, ihe St. Peter sandstone la one of the aquifers in the Twin City area. It is not used too extensively in the downtown metropolitan areas but la used to a large degree for shallow walla in the rural areas. Jinere are undoubtedly numerous wells in Cottage Grove, one mile to the south, which obtain their domestic wster from the St. Peter sandstone. This 3MA00335961 Trial Exhibit 3 3M MN00000135 Ar. Hans weasel - 2- July 13, I960 aquifer is not protected ay e shale or a limestone layer over the top except on the very eastern edge of the proposed site. In general, this area lies on the west flank of the Alton anti-eilne and this sandstone formation dips slightly in a westerly direction and it is felt that the principal water seepage would be along that lins towards the center of the Iwin City basin. Along tha eastern edge of the proposed site, there is s band of Platt- villa limestone which is probably not over 20 feet thick overlying the St. Peter sandstone. I h a limestone also dips in a slight westerly direction. From our preliminary investigation it appears as if there la 10 to 20 fast of ovarburden or drift along the west edge of the property and there is considerable gravel and reworked drift as you proceed into the valley or pocket near the center of the site (see map). On tha eastern 30 acres there could well be 30 to 75 feet of glacial drift. The exact depth of the location of these formatIona1 contacts will have to await boring information. From a geological standpoint this area would not be Ideel in our opinion; however, from the other merits of this location we feel it should satisfy our demands. If there is a large volume of acid waste dumped, it would be better if the area ware immediately underlain by a thick formation of llmestons or dolomite. This would help neutralize the acid before getting into the ground water, dries cottage 'drove is at least a mile aws y, it is felt that the water would have sufficient distance to purify itself. Other wet wastes, not neutralized nor deposited within rock or soil pore spaces, will eventually reach the water table and pollute domestic wells. It appears that the ground water elevation in this area la approximately 360 feet above sea laval and our principal dumping ar* will be at about 900 feet, xherefore, waste seepage will travel considerable distance before reaching the water table. eventual pollution of adjacent domestic wells will depend upon time, geologic conditions and rate of wet waste dumping.r when waste seep age reaches the water table certs In solids by that time may be ren dered harmless while others will remain to pollute wells. The geologic conditions that will effect pollution ere location and thickness of the limestone cap over the St. Feter sandstone, to neutralize acids and prevent early contamination of aquifers; direction of dip of feeds and direction of flow of the ground water; and amount and porosity of glacial drift. Five or six borings will answer most of these questions. The other fector, rate of dumping, will hasten or prolong pollution, degree of pollution will in turn indicate the time when dumping should cease. It may be that other factors will signify a time to abandon the site prior to maximum pollution, .hose factors would be housing devel opments, publio relatione, end new zoning regulations. The zoning problem alone merits s good deal of attention. Lew level lend usage such es dumps, and gravel pita generally brings condemnation from nearby residents and population centers. This cannot be over emphasized after past experience with cur eastern zoning problems. 3MA00335962 3M M N00000136 3 Mr* Hans vessel July 13, I960 It Is imperative that we have absolute freedom to use the land for dumping before purchase and use. After this is obtained, the land purchased and holes bored, the geologic conditions should be utilised to plan dumping in such a manner as to realise the longest possible life for the dump with the least possible aquifer pollution. In conclusion, we would like to recommend that four to six borings be made along an eaat-weat line In approximately the center of the property (see map), This will give information on the formations! contact between the St. Peter sandstone end the Plsctvllle limestone and the exact depth of glacial drift. It is felt that if at all p o s sible, our wet waste trenches should be constructed over the Plattkllle limestone bedrock. Observation wells should be maintained and periodic analyses made to determine the extent of pollution. These wells may be the wells already on the property, eased exploratory bore holes, neighboring wells or wells drilled expressly for the purpose, rhese would give us information on rate of pollution and allow us to predict a time to cease dumping. Prom our preliminary survey we feel that this area will make suitable dumping site. This report is a result of field survey and study by the Geology Department. JAB/eb 3MA00335963 3M M N00000137