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DEVELOPMENT OF DEPOSITS Another basic assumption made in setting up the Colorado State University project was that once the deposits of suitable clay were located> they would be developed commercially. Excellent pro- gress in this direction has been made--especially in the Arkansas River and Colorado River areas. A major part of the development work has been done by local earth-moving contractors--wit h lesser amounts by irrigation companies, local pros- pectors, and lease speculators. Since, in general, the market for the clay product, as well as the deposit itself, must be developed, the major tonnage of clay has been sold by those equipped to install as well as mine and process the clay. As perhaps to be expected in any new industry, the quality of the produced material varies widely. Quality control is needed and those of you that are potential buyers of clay can help by buying on a basis of quality rather than price alone. In addition to the characteristics discussed previously under CLAY TESTING, a high quality clay will have the following characteristics: 1. Low impurities content -- If the deposit is clean-stripped of overburden materials before mining of the clay. this normally will control this quality problem. 2. Low moisture content - - The clays in the deposits commonly have from 20 to 50 per cent mois- ture content. Before use the moisture content shoukl be lowered to less than 20 per cent. With proper mining procedures, the mois- ture problem and several other problems, such as variability of clay and size of lumps, can be con- trolled satisfactorily. An adequate mining operation will he characterized by the following: 1. Overburden - - The overburden should be removed over a large area rather than one small or several separate small areas. 2. Air-drying -- During dry weather, the clean-stripped clay layer should be harrowed or loosened to assist in the air-drying process. A south-facing slope will work best for the air-drying process. 3. Stockpiling -- To assist in mixing the clays to obtain a uniform clay product, the clay should be stockpiled after air-drying. 4. Lumps -- With adequate air-drying, most clays will break down to fragments of 1/2-inch or less in diameter. If larger lumps are present. additional processing is needed. The amount of processing required to pro- duce a uniform clay material for sealing purposes can be reduced significantly by the mining procedure, but since the air-drying operation in the open pit mine is vulnerable to weather, processing equip- ment for artificial drying, grinding and screening will be desirable in the advanced developments. Limited investigations into processing equipment have been made and one experimental set-up of grinding equipment in a clay processing mill is being observed and evaluated. As to future work in this regard, when requested, assistance will be provided to clay pro- ducers including both laboratory testing and develop- ment recommendations. In addition. the possibili- ties of specifications for clay sealing materials will be explored during the coming year--both with the clay producers and with the SCS, ASe. and Extension people in areas where Clay-sealing work is being accomplished with federal cost-sharing assistance. 1052 5