LIMONITE STOCK LICK

Otago Daily Times, Issue 23118, 18 February 1937, Page 3

LIMONITE STOCK LICK

DEPARTMENT OF AGRICULTURE BULLETIN VALUABLE COBALT CONTENT Samples of limonite rock from the Okaihau quarries recently tested have been found to be very variable in cobalt content. Among the deposits being worked are some that contain over 250 parts per 1,000,000 of cobalt. To secure reasonable uniformity the company working the deposits is now selecting the rock so as to result in a product of anticipated cobalt content of 200 parts per 1,000,000. A sample of such ground material ready for distribution gave a figure of 210 parts per 1,000,000. The Department of Agriculture has arranged for systematic supervision of the commercial samples of limonite offered for sale to ensure that the specified content of cobalt is satisfactorily maintained. Recent experiments indicate that cobalt is the element present in limonites which is chiefly responsible for their beneficial effect when used as stock lick in bush-sick country. Ruatangata limonite, which has given such good results, usually contains from 50 to 100 parts per 1,000,000 of coball but it is quite probable that deposits of higher cobalt content may exist in this locality. There arc some indications that nickel, zinc and perhaps other trace elements may exert a beneficial effect in addition to that of cobalt, so that it is impossible at present to evaluate a limonite for slock lick purposes solely on its cobalt content. The determination of some of these trace elements in a variety of limonites is at present in progress and will bo reported upon later.