Page:Transactions NZ Institute Volume 15.djvu/476

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in composition, and, as previously mentioned, the top and bottom of the same seam will frequently be quite different:—

	Fixed carbon.	Hydro- carbon.	Water.	Ash.
Springfield	47.90	41.80	6.30	4.00
Brockley	49.99	35.22	11.79	2.80
Springfield	50.60	38.80	7.80	2.80
Ayers (thin seam)	52.01	3.69	4.89	39.41
Brockley	53-29	32.04	12.65	2.02
Hill's mine	53.30	33.97	9.98	2.75
Springfield	55.50	30.90	4.20	9.40
Hill's mine	59.39	33.78	3.89	2.94
Williamson's	61.90	26.80	.90	10.40
Kowhai	61.10	35.40	1.60	1.90
Ayers (thick seam)	62.21	18.99	5.20	13.60
Springfield	63.20	23.60	3.20	10.00
Rakaia Gorge	64.51	21.27	6.76	7.46
Acheron	65.80	5.38	4.57	24.25
Kowhai	66.10	14.10	2.20	17.60
Malvern Hills	67.49	17.89	2.12	12.50
Hart's mine	69.62	14.92	2.77	12.69
Malvern Hills	73.94	16.60	3.60	5.86
Kowhai	80.01	10.95	6.50	2.54
Malvern Hills	83.20	12.10	2.20	2.50
Acheron	88.91	—	3.17	7.92

Semibituminous Coals.—The only coals of this class of which anything are those from the well-known Kawakawa colliery at the Bay of Islands, the output from which for the year 1881 was 50,277 tons, or about ¹⁄₇ of the total quantity of coal raised in New Zealand during that year. The mine is worked in a seam which is from 4 feet to 15 feet thick, and the coal has an average composition of—

Fixed carbon	55.59
Hydro-carbon	38.10
Water	4.19
Ash	2.12
	100.00

It varies a good deal in its physical characters, being sometimes exceedingly hard and at others quite soft, but the composition is moderately constant. It is an excellent steam coal, and is largely used on the coasting steamers.

The same class of coal also occurs at Preservation Inlet in Otago, where it is found in thin impure seams, having the following average composition:—

Fixed carbon	61.37
Hydro-carbon	28.06
Water	4.37
Ash	6.20
	100.00