LIMONITE FOR STOCK-LICK PURPOSES

New Zealand Journal of Agriculture, Volume 54, Issue 3, 20 March 1937, Page 175

LIMONITE FOR STOCK-LICK PURPOSES

Chemistry Section, Department of Agriculture, Wellington

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 million 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 million. A sample of such ground material ready for distribution gave a figure ■of 210 parts per million. 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 million of cobalt, but it is quite probable that deposits of higher cobalt content may exist in this locality. There are 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 stock-lick purposes solely on its cobalt content. The determination of some of these trace elements in a variety of limonites is in progress, and the results will be reported later.