Art. XLIV.—On the Occurrence of Tellurium in the Thames Lodes.
[Read before the Auckland Institute, 22nd October, 1888.]
In the year 1884 I received some rich stone from Mr. E. H. Whitaker, whose assay showed it to contain silver to the extent of 3,928oz., and gold 234oz. to the ton. This was from the Moa Claim, at Te Aroha. The suggestion to examine these specimens for tellurium was given by Sir James Hector, to whom I submitted them, and who confirmed the fact of tellurium being present on his return to Wellington. In the meantime I had determined the constituents of the ore, the analysis of which I append.* This exceptionally rich stone naturally led to further investigation of the ground, showing that it occurred in exceedingly narrow veins, occasionally widening to the width of an inch, or slightly more. In the richer portions the telluride is accompanied by anti-
[Footnote] * Analysis not received.—Ed.
monide of silver and free gold. The telluride is irregularly disseminated throughout the stone in the massive state and also in fine granules. In colour it is steel-grey, with metallic lustre, and it is readily crushed. It is always accompanied by magnetite in fine grains, and sometimes by ilmenite.
Anticipating that it would be found in other portions of the district, I have examined a large number of the richer portions of the lodes, with the result of finding it in combination with the silver in the Crown, Woodstock (Maria Reef), and Ivanhoe Mines, at Karangahape; in the Champion and Lord Nelson Mines, at Te Aroha; and as a trace only in the Rosemont Mine, at Waihi. That this metal is present in much larger quantities than is generally anticipated I feel convinced, and when proper examination of the ores is made before treatment we shall find a great deal more consideration given to the presence of tellurium than has hitherto been the case. Experience already gained elsewhere has shown this metal to be very inimical to the saving of gold or silver combined with it; and, as I have found it present in some of the Crown ore to the extent of 4·18 per cent, it will be seen that it is a factor which will require to be considered when an economical and satisfactory mode of saving the riches of our lodes is adopted.