ANNUAL ADDRESS. XXXI. 



making our engineering shops busy constructing machinery for 

 dredging gold bearing wash-dirt 1 ? 



This industry appears to have originated in New Zealand, not 

 earlier than twenty years ago. The appliances then used were 

 the old "spoon and bag," worked from a pontoon, and as much 

 as thirty ounces of gold per week has been won with this primitive 

 appliance, having only one man at the pole, and one at the 

 windless. In 1876 current wheel dredges were introduced; these 

 had a large paddle or undershot wheel, moved by the current 

 which worked the dredge buckets ; it also raised the water for 

 sluicing. Some of these machines are still at work. 



The first steam dredge for gold seeking was built in 1881, the 

 dimensions of the hull being 75 ft. by 18 ft. by 3 ft. 6 in., the 

 capacity of the buckets If cubic ft. each. The largest gold dredge 

 at present in existence, is said to be 120 ft. by 10 ft., with buckets 

 each of 7 cubic feet capacity, and capable of lifting 180 cubic yards 

 per hour. The average cost of this dredging is about 4d. per 

 cubic yard, but it can be done for Id. in favourable ground. The 

 greatest depth at present worked is 45 ft. under water, the greatest 

 height delivered 25 ft. above water, or 70 ft. in all. But depths 

 have been worked to 60 ft., and tailings have been lifted to 40 ft. 

 Seven men will attend to the largest dredge working continuously, 

 that is, a general manager, and two men for each of the three 

 shifts, every necessary operation being performed by the machinery. 

 These dredges are now being worked in nine different countries 

 by men from New Zealand ; probably because New Zealand was 

 the first to start dredging for gold. In New South Wales, Mr. 

 Garland was the first to introduce a dredge on the Macquarie 

 River. Up to the presnt time over 32,000 acres have been applied 

 for in the State under dredging leases, by 460 applicants. An 

 average size gold dredge costs about £6,000, and the largest and 

 most perfect ones double the amount. 



This industry has led to an entirely new branch of engineering 

 being established in Sydney, and I am indebted to Mr. C. E. 

 Richardson, of the firm of Richardson and Blair, who are specialists 



