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Cost of Mining. —The cost of clay delivered at the works is stated as, at the Brunner Mine, 7s. per ton; North Brunner Mine, Bs. 3d. per ton. Number of Men employed. —There are no men employed underground in producing fireclay alone, as it is mined by the colliers with the coal and handled by the coal-truckers. The work done underground, however, is equivalent to the work of six men at North Brunner Mine, and four men at Brunner Mine. The men employed on the surface are, at North Brunner, nine; at Brunner, eleven. Method of 'Treatment. —The fireclay on coming from the mine is stacked at the surface and exposed to the weather until it begins to crumble, when it is said to be tempered. It is then crushed under heavy rollers and passed through fine screens. The crushed clay passes into a pug-mill, where it is mixed with water to the necessary consistency for moulding. The moulded bricks or other articles are placed on a heated floor to dry, and when dried they are stacked in kilns and burnt hard. Classes of Brick, &c, manufactured. —Firebricks are made in all required shapes, also tiles, locomotive-blocks, air-pit fire-grates, flue-covers, &c. Any article required in fireclay can be made. Plant in Commission. —The plant in use at each mine consists of a set of steam-driven roll screens, elevator and pug-mill, drying-sheds, and kilns. Moulding is at present done by hand. Estimated Life of the Industry.- —The present output of clay from the mines is about 6,000 tons per annum, and if that rate of consumption be maintained there is enough clay proved to last for, say, fifty years; but this will depend upon whether the demand becomes greater or less than at. present, and also upon whether the cost of mining clay apart from the coal will prove low enough to enable the industry to be carried on after coal-mining ceases. If our anticipations regarding probable clay be realized the supply of raw. material will last for several generations.