C—l 4

186

Barometer Readings (reduced to Sea-level), Auckland. September 1.. .. .. .. 29-78 September 9.. .. .. .. 3023 2 .. .. ... .. 29-78 „ 10.. .. .. .. 30-32 3 .. .. .. .. 29-93 „ 11.. .. .. .. 30-28 4 .. .. .. .. 30-02 „ 12.. .. .. .. 30-25 5 .. .. .. .. 30-03 „ 13.. .. .. .. 30-28 6 .. .. .. .. 30-08 „ 14.. .. .. .. 30-22 7 .. .. .. .. 30-14 „ 15.. .. .. .. 30-33 8 .. .. .. .. 30-10

EXHIBIT S. (Apparently a duplicate of Exhibit CC, p. 179, but with several slight differences.) Dominion Laboratory, Wellington, N.Z., 29th September, 1914. Report on Specimens No. E/1144, 1145 (1-3), 1146 (1, 2), forwarded by Mr. F. Reed, Inspecting Engineer. Particulars: Samples in connection with recent explosion in Ralph's Colliery— E/1144, single piece of coal; E/1145 (1-3), coaldust from mine; E/1146 (1, 2), brattice-cloth. Analyses of the coaldust and coal gave the following results:—

A microscopic examination showed that 1145 (2) contained a considerable number of charred particles. In the case of 1145 (3) it is doubtful if there are any charred particles, but in 1145 (4) there are undoubtedly some. The brattice-cloth when examined under a lower power gave undoubted evidence of singeing, and the dust on it also proved to have been charred. In order to determine the inflammability of this coal I have made the following experiments : A small amount of coal, ground to pass through a fine sieve (100 holes to the linear inch), was blown through a glass tube across the flame of a Meker burner (fixed horizontally) towards a piece of cottonwool supported in a clamp. By varying the distance of the cotton-wool from the flame of the burner it was possible to measure the greatest distance at which the coaldust flame would ignite the wool. Four coals ground to the same degree of fineness were examined by this method, and, as a result of a number of determinations, I have found the distances to be as follows : — Distance at which Coaldust Flame ignited Cotton-wool. Inches. Huntly E/l 144 (brown coal) .. .. .. .. .. ..20 Westport-Stockton (bituminous coal) .. .. .. .. ..16 Aberdare Collieries, New South Wales (bituminous coal) .. .. 13 Wales (anthracite) .. .. .. .. .. .. .. 2| These results show that the Huntly coaldust is very inflammable, and that the flame of the ignited dust travels greater distances than ordinary bituminous coals such as Westport-Stockton and Aberdare. Such properties would render the coaldust very effective in carrying on and intensifying an explosion once started. The four coals referred to above gave the following results on analysis:— Fixed Carbons. Hydro-carbons. Water. Ash. Huntly .. .. .. •• -. •• 44-23 41-07 13-14 1-56 Westport-Stockton .. .. .. .. .. 58-50 39-98 1-34 0-18 Aberdare .. .. .. •• ■• •• 52-54 41-59 2-46 340 Wales (anthracite) .. .. .. .. .. 89-07 6"51 2-27 2-15 J. S. Maclaurin, D.Sc, F.C.S., Dominion Analyst. Reference : No. 13, dust from bord W.C., No. 5 district; No. 14, dust from near No. 6 cabin haulage-roadway ; No. 15, dust from main haulage-roadway at No. 4 level; No. 16, dust from piece of Ralph's Colliery coal; No. 17, dust from near flat sheet No. 5 jig.

E/1144. E/1145 (2), E/1145 (2), No. 13, on through 30 mesh. 30 mesh. 1145 (3), No. 14, on 30 mesh. 1145 (3), through 30 mesh. 1145(4), No. 15, on 30 mesh. 1145 (4), through 30 mesh. 'ixed carbon [ydro-carbons 44-23 41-07 13-14 T56 42-7 40-9 12-3 4-1 44-1 38-7 10-1 7-1 35-3 36-0 13-0 15-7 33-6 34-7 12-9 18-8 22-8 30-5 8-8 37-9 24-9 35 3 9-5 30-3 Skater .. .sh 100-0 100-0 100-0 100-0 100-0 100-0 100-0