1070 LAWS OF MARYLAND. [CH. 437

142B. Cap lamps and checking systems. All workmen
and other persons underground shall use only permissible
electric cap lamps for portable illumination. This does not
preclude the use of other types of permissible electric
lamps. Mines now operating with open-light equipment
may continue to so operate until permissible electric cap
lamps can be secured from suppliers, or until necessary
facilities for service of such equipment are available.

142C. Arcs, sparks, and flames. Because of explosion
and fire hazards, all persons in underground workings of
a mine are herewith prohibited from intentionally creating
any arc, spark, or open flame, except those that cannot be
avoided in the normal performance of work. The carrying
of matches or other flame-making devices into a mine and
smoking shall be prohibited.

142D. Welding and cutting (with electricity or flame)
shall be restricted to places where trolley locomotives are
permitted except that where it is necessary to do welding
and cutting in face regions, such work shall be under the
direct supervision of a certified official, who shall test for
gas before starting operations and frequently thereafter.
In all welding and cutting operations, precautions shall be
taken against starting a fire and the area shall be rock-
dusted.

EXPLOSIVES AND BLASTING

144. Surface magazines, (a) Separate surface maga-
zines shall be provided for the storage of explosives,
detonators, and Cardox heater elements. Surface maga-
zines for storing and distributing high explosives in
amounts exceeding 125 pounds shall be:

1. Reasonably bulletproof and constructed of incom-
bustible material or covered with fire-resistive material.
The roofs of magazines so located that it is impossible to
fire bullets directly through the roof from the ground, need
not be bulletproof, but where it is possible to fire bullets
directly through them, roofs shall be made bullet-resistant
by material construction, or by a ceiling that forms a tray
containing not less than a 4-inch thickness of sand, or by
other methods.

2. Provided with doors constructed of 3/8 inch steel
plate lined with a 2-inch thickness of wood, or the equiva-
lent.