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The bottom seam has been bored and explored in relation to its continuity and depth under the top seam, arid a recent borehole proved that the intervening post of fireclay between the seams is thinning to the east to such an extent that the future development of the bottom seam could be more advantageously followed by a connection from the top seam, and its established system of haulage and ventilation. Bv arrangement, the neighbouring colliery companies dump the bulk of their unmarketable slack coal near the Rotowaro Mine. The dump contains 50,000 tons, and vigilant attention is required to prevent the heap firinp*. 'Pulcemiro Collieries (Pukemiro Collieries Ltd., Owners). —Operations during the year have been confined to the extraction of the pillars in the east and north mine sections. In the east section the pillars have been withdrawn to the jig head, and only roadside pillars remain for extraction. In the north mine section, comprising four working districts, the work of depillaring has been continuously carried out in all districts, and-no extensive areas of solid coal remain for working. The seam varies from 8 ft. to 16 ft. in thickness, and the roof-cover averages 80 ft. At this shallow depth 30 per cent, of the coal was got by the first working, and at least 60 per cent, is now being won from the extraction of the pillars. The system of endless-rope haulage to the faces has been maintained with satisfactory results as regard haulage costs. Drainage, from the pillar sections which are liable to be flooded through breaks to the surface caused by pillar-extraction, has been discharged from the workings through the drainage pipes laid out to the surface before pillar-extraction was commenced. An average daily output of 530 tons was maintained during the year. The south mine section, with bords completed to the boundaries, was not reopened for output. This section is being maintained in working order should the demands of trade warrant additional output. Glen Afton No. 1 Colliery (Glen Afton Collieries, Ltd., Owners).—The total output since the commencement of mining operations by the company amounts to almost 2,000,000 tons; of that quantity 1,532,323 tons have been extracted from No. 1 Mine. Operations, as during the previous year, have been confined solely to the extraction of pillars in K3 and K4 Sections, the farthest inbye sections in the mine. There is a roof-cover of about 400 ft. of fireclay and limestone over the workings, and the adopted method of pillarextraction, in straight line, is resulting in a high percentage of pillar coal being extracted under favourable conditions as regards safety and control of the roof weight. The floor is yielding to the weight, and many renewals of roof-timber supports are required before the pillars are completely extracted. The dust on the roadways is dry, and increasing quantities of incombustible dust are applied to the roof, sides, and floor of the roadways in treatment of the coal-dust produced in working, and from fretting of small coal from the pillars. The panel system is adopted, and huge reserves of coal remain in the 1-chain-square pillars formed to the boundaries of the first working. Haulage and ventilation have been maintained at a high standard, and generally the mine is equipped and developed for double the present output should it be required. Glen Afton No. 2 Colliery (Mac Donald State Coal-mine Reserve under lease to the Glen Afton Collieries, Ltd.). —The output for the year, 139,985 tons, was derived from the first working. Three coal-cutting machines are employed in the faces, all of which are machine-cut. The average daily output per miner is 13 tons. The main west headings have been advanced to the dip within eight chains of the boundary. The panel system, with substantial barriers between panels and roadways, is being carried out, and modern methods of mining are practised throughout the field. The seam averages 15 ft. in thickness, and, as the coal is strong and the bords are only driven to a height of 9 ft., safe roof prevails in all the working-places. In the north section the main headings have been extended 36 chains in workable coal to an outcrop from which a drain-level can be connected for the drainage of water in the rise sections. Six panels of workable coal have been formed, and in the course of formation in this section, and, as the districts are conveniently situated and connected by subsidiary haulages to the main haulage system, a large output could be obtained. The field has been extensively prospected by boring, with the result that a system of laying out the sections can be planned from the record of bores and topographical surveys. Graham Colliery (Party of Miners, Owners).— Operations during the past year have been confined to the extraction of the pillars from the southern boundary. The seam is from 3 ft. to 4 ft. thick. Two headings are proceeding to the west in an endeavour to locate another workable area. The output is connected to rail near Glen Afton Railway-station. Waikato Extended Colliery (Roose Shipping Co., Owners).—This small coal-mine, situated on the west bank of the Waikato River three miles south of Huntly, and owned by the Roose Shipping Co., was worked for the production of fuel for the company's river steamers. Pillars were extracted from the barrier left between abandoned workings. Huntly Brick Works.—An opencast fireclay quarry is in operation to supply the company's brickmaking and tile plant established on the ground. The faces were maintained in safe order. Taupiri East Colliery (Auckland University Council Endowment Lease). —A party of miners is still engaged in splitting the rise pillars of the old Kimihia Mine dip. The seam is 18 ft. thick, and places 10 ft. wide by 12 ft. in height are driven through the pillars. Boreholes at frequent intervals are drilled into the roof for testing the thickness of overhead coal. Electric power is connected to the pump and winch. Campbell Colliery (Crown Lease, Whatawhata). —Little development has been carried out during the year, and operations have been confined to the extraction of pillars in the dip section where a series of faults prevents dip extension. Close attention to a fire in old workings, fanned by air, breathing through loosely packed surface falls, was required to prevent the fire spreading to the new dip area. The output satisfies a demand in the Raglan and Frankton districts. Renown Colliery (Renown Collieries, Ltd., Owners). —The total output, from the commencement of operations seven years ago, has reached the half-million mark, and the coal yet to be won lies conveniently within working distance of the main roadways and installed haulages. The pillars have been extracted from No. 3 and No.. 4 south sections. In No. 2 south and No. 3 north sections bords of the first working are still proceeding to the boundaries of the panels. The main headings, turned south at No. 4 section, have been extended 20 chains in provision of two additional sections. No development work was done in No. 1 south section, where an area of proved coal lies ahead. A roof-fall of considerable magnitude occurred on the haulage road in this section, and an attempt made to retimber a roadway through the fall was abandoned owing to the moist condition of the fallen claystone. The roof and sides of a portion of the return airway through a faulted zone, where the timber supports had only a short life due to a highly saturated mine atmosphere, have been supported by steel arching of elliptical shape, lined with durable timber laths. The seam generally is moderately inclined, and after the advancing headings have made available one or more sections for machine work one of the headings is widened and straightened in provision of subsidiary haulage and an intake airway. Two coal-cutting machines have been continuously employed in holing 90 per cent, of the working-faces. Prior to the completion of pillar-extraction in No. 3 south panel a crushing movement, attended by a heating of the goaf, necessitated the erection of brick stoppings to seal off the affected area. Wilton Colliery (Wilton Collieries, Ltd., Owners). —The main headings have been advanced 48 chains through a narrow area of clean coal averaging 11 ft. in thickness. Endless rope haulage has been extended to within working limits of the faces and the haulage costs reduced accordingly. In No. 2 dip section the pillars have been withdrawn back to the dip-supporting pillars. The first working of No. 3 dip section is completed to the outcrop boundary. Concentration on output is confined to the rope-end section. The seam in this section occurs at a shallow depth and 1-chain-square pillars are formed in the first working, leaving 80 per cent, of the coal in reserve for pillar-extraction. Two drives have been turned out to the surface in the rope-end ee/'Jon in provision of intake airways and a third means of escape for the workmen. The coal is generally friable Bad jointy, and therefore easily mined. Occasional shots are fired for dislodging stone balls in the seam. A total of 83,101 tons was produced during the year, and 150 men were ordinarily employed in tlie mine.

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