WM. PRESTON LANE, JR., GOVERNOR. 1067

(b) Trailing cables shall be provided with suitable
overload protection and power taps, unless properly con-
nected to permissible junction or distribution boxes.

(c) The number of temporary, unvulcanized splices in
a trailing cable shall be limited to four. The number of
temporary, unvulcanized splices in a short hand cable shall
be limited to one.

Trailing cable splices shall be made in a workmanlike
manner, mechanically strong, and well insulated.

119D. Underground Illumination. Electric light wires
shall be supported by suitable insulators and fastened se-
curely to the power conductors by means of clamps or the
equivalent.

Electric lights shall not be installed within 150 feet
of pillar workings or advancing workings.

Electric lights shall be installed so that they cannot
come in contact with combustible materials.

COAL AND ROCK DUST

138. Control of coal dust. Coal dust shall not be per-
mitted to accumulate excessively on roadways and along
conveyor lines. Where mining operations raise an exces-
sive amount of dust into the air, water or water with a
wetting agent added to it or other effective methods shall
be used to allay such dust at its source.

138A. Rock dusting, (a) All mines, except those mines
or those locations in a mine in which the dust is too wet or
too high in incombustible content to propagate an explo-
sion, shall be rock dusted to within 60 feet of all active
working faces, and all open crosscuts within the 60 foot
zone shall be rock dusted. However, if the dust in a mine
or any part of it is wet but becomes dry, the mine or por-
tion of the mine so affected shall be rock dusted as soon as
it becomes dry.

(b) In mines rock-dusted partially or in mines that
are required to start rock dusting, haulageways and paral-
lel entries connected thereto by open crosscuts shall be
rock-dusted. Back entries shall be rock-dusted for at least
1, 000 feet outby the junction with the first active entry.
Inby this junction, the rooms, entries, and crosscuts shall
be rock-dusted by generalized rock dusting as provided for
in the preceding section.

(c) Where rock dust is applied, it shall be distributed
upon the top, floor, and sides of all open places and main-