STATISTICS AND INFORMATION. 2801

1922, ch. 307, sec. 137.

138. In any portion of a mine where an undue quantity of dry dust
or other waste material accumulates and may tend to cause an explosion,
and especially when explosive gas is being generated in quantities suffi-
cient to he observed with an approved safety lamp, the operator shall, sub-
ject to regulation of the Bureau, keep such dust, and the haulage ways
and working places containing the same, well moistened with water often
applied, or shall use other efficient, approved means; and shall remove
such dust from the mine at frequent intervals.

1922, ch. 307, sec. 138.

139. Whenever any place is being driven towards or is in supposedly
dangerous proximity to an abandoned mine suspected of containing ex-
plosive gases or which may contain a dangerous accumulation of water,
bore holes shall be kept not less than twelve feet in advance of the face and
on the sides of such working place, said side holes to be drilled diagonally
at intervals not exceeding eight feet. No places so driven to tap water or
gas shall be more than ten feet wide; and no water or gas accumulation,
nor any bore holes from the surface, shall be tapped until all employees
except those engaged upon such work are out of the mine. Such work
shall be executed only under the immediate supervision of the mine fore-
man. Provided, that coal shall not be mined within fifty feet of any
abandoned mine, suspected to be inundated with water, until danger from
such water has been removed by driving a passageway to tap and drain it
off; and Provided, further, that barrier pillars standing in the vicinity of
such abandoned mine shall be in proportion of one foot of additional pillar
thickness to each one and one-quarter feet of water-head, if in the judg-
ment of the district mine inspector such thickness is necessary for the
safety of persons and property within the operating mine.

1922, ch. 307, sec. 139.

140. Whenever clay veins, spars or faults are cut in driving entries
or other narrow work into solid coal, in gaseous mines, a bore hole shall be
kept not less than three feet in advance of the face or a like distance in
advance of any shot hole drilled for blasting.

CHAPTER XX—Fire Protection.
1922, ch. 307, sec. 140.

141. All underground storage, motor, pump and engine rooms shall
be constructed of incombustible material; and it shall be the duty of every
operator to provide and maintain some efficient means of fire protection
approved by the Bureau, at such points as the Bureau may prescribe. No
steam pipes shall be laid within any such mine, unless insulated with ap-
proved material.

1922, ch. 307, sec. 141.

142. No building shall hereafter be erected within such distance of
any ventilating fan, or entrance to or exit from any main airway, shaft,
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