1986-12-08_GENERAL DOCUMENTS - M1977493 (2)

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i was applied to the moistened tailings in amounts costing 1 cent • adhesive type, re yard. This stabilization procedure generally is best +I ' or less per squa y � applied in the fall of the year so as to achieve some growth before the onset of winter, thus allowing the root system to develop under a cover of snow an ` with good moisture conditions. •'� ; Field Tests A combination system involving vegetWinonuntilathe application coverfwCsherex able to stabilize the surface against sand blowing to take over that function itself was developed from knowledge acquiredfrom a the Bureau laboratory and outdoor trials. That system was applied 10-acre plot of Kennecott's McGill, Nev. , tailings in mid-September of 1967. The McGill tailings are located in a climatically harsh site for vegetation. The growing season is short, the temperature range is wide, and pubescent , is only 8.4 inches per year. Different proportions of western, pjr;,, , and tall wheatgrasses , Russian wild rye crested, intermediate, , Ladak and i4i,'+i',1 y Ranger alfalfas , yellow sweet clover, winter wheat, and Siberian pea tree �: ; ;4. seeds were mixed and planted by drill seeder at a rate of about 15.5 pounds per acre foot. Prilled urea and superphosphate far- or 37 seeds per square tilizers were added to the seeding mixture at a rate of about 45 pounds per „ mixture s planted in acre each of P205 and nitrogen. rior to discovering- furrows ing- thatnitrogencins apart. (This field test was conducted p Aweek after the area was this quantity tends to inhibit legume germination.) F= ;. seeded, Coherex diluted with 4 parts of water was applied over the entire area. indicated that approximately 0.25 gallon per square Laboratory studies had would satisfactorily stabilize McGill tailings. To hard of diluted Coherex 2-1/2 and 2-1/2 acres were sprayed # corroborate these laboratory finds, 5, ! ! with 0.25, 0.18, and 0.67 gallon per square yard, respectively. tcI ith An accounting was kept of material and application costs associieCiable treatment of the 10-acre plot. During a year of observation, no appreciable differences were noted in the stabilization of plots treated with the differ- amounts of Coherex. This indicates tha ent t the preselected quantity of ent solution could be reduced to 0.25 gallon per square yard of dilute Coherex 0.18 gallon per square yard with a savings in cost. The estimated cost of $1,355 for the 10 acres could probably be reduced if larger acreages were :ill treated or if proper equipment were available. Such a cost for the chemical- vegetative procedure compares favorably with that of chemical stabilization only, which cost $335 per acre in the Tuba City test. Many violent windstorms have passed through the McGill area during the I ' 6 years since planting, without raising dust clouds from the stabilized plot. The Coherex satisfactorily maintained the surface until the vegetation grew and the chemically and vegetatively stabilized tailings now appeary resistant to wind erosion. No irrigation was applied to the plot during the 6years , but the growth was excellent. The plot, as of September 1972, sho�aed that a line of vegetative ecological succession had been established in that approximately 27 different plant species were on the area and growing well, 17 of which were encroaching native species. The success of the combined chemical-vegetative stabilization procedure at McGill, Nev. , prompted testing of that method in other localities with