IV. — CHEMISTEY. 



Art. XLIII. — Oji the Manganese Deposits of the Auckland 



District. 



By J. A. Pond. 



[Bead before the Auckland Institute, 17th December, 1888.] 



The existence of manganese in various parts of this district 

 has been recorded for many years, but it is only during the 

 last ten or twelve years that any large quantity of it has been 

 dealt \\ith commercially. It was first mined on a large scale at 

 "Waiheke, and next at the Bay of Islands, since which consider- 

 able quantities have been sent from Whangarei. The mines 

 at the Bay of Islands, and also at; Waiheke, have been worked 

 extensively, and have yielded a large tonnage of excellent ore 

 while luider the successive managements of Mr. Stovin, Cap- 

 tain Phillips, and Mr. Kersey Cooper. At the former place 

 the chief workings were connected by a wire tram with the 

 water, the motive-power being obtained from a stationary 

 engine secured upon a moored punt, the manganese ore being 

 discharged into punts, from which it was transferred to vessels 

 for transmission to Auckland, the shallow water of the bay 

 making it necessary to adopt this tedious method of loading. 

 At Waiheke the ore was carted for some distance to the 

 water's edge, where it was placed directly in the cutters and 

 transferred to Auckland. At this port the ore was discharged 

 into homeward-bound vessels, where it was of value in stiffen- 

 ing the ships which w^ere loading home with wool, and was 

 consequently taken at low freights, proving a valuable ballast 

 owing to its high specific gravity. 



In the mines the ore was found in bunches sometimes 

 yielding several hundred tons of ore, which was brought to 

 the dressing-floor and carefully picked over, as it was seldom 

 possible to ship it direct owing to nodules of haematite and 

 clay-masses, together wdth a good deal of siliceous gangue — the 

 " flucan " of the miners — which tended greatly to reduce the 

 value of the ore unless removed. Sometimes this siliceous 

 gangue was stained black by the peroxide of manganese, 

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