334 LAWS OF MARYLAND. [CH. 188

Entry means a passage way in a coal bed which is approxi-
mately level and is used for haulage, traveling way, or venti-
lation. In a dipping bed, entries on the strike are known as
"levels" or "gangways" and to the dip are known as "slopes".

Excavations and Workings: The term "excavations and
workings" includes all the excavated portions of a mine,
whether abandoned or being worked; also all underground
workings and shafts, tunnels, and other ways and openings,
and all such shafts, slopes, tunnels, and other openings in the
course of being sunk or driven, together with roads, appliances,
machinery and material connected with the same below the
surface.

Faces: The term "face" shall mean the advancing breast of
a mine working-place, either of an entry or room.

Gas is used in the sense ordinarily employed by miners, to
mean "fire damp", and inflammable gas, chiefly composed of
methane, sometimes accompanied by ethane (C2He) in case of
leakage of natural gas, and explosive when mixed with air in
certain proportions.

Gaseous Mine is one in which methane occurs in the mine
atmosphere in such quantities as may become dangerous. If
the percentage of methane in the main return exceeds one half
of one per cent., or in any split, or single return exceeds three-
tenths of one per cent., the mine shall be considered a gaseous
mine. Samples of the mine air shall be taken in duplicate for
testing purposes when the ventilating current in such mine and
mine conditions have been normal for at least twelve hours;
and when a sample is found to exceed the limits, duplicate
samples shall be taken and tested. If the first results are con-
firmed the mine shall be rated as gaseous.

Whenever the operator of a mine previously rated as gaseous
shall improve the ventilation thereof until the percentage of
"methane in the main return falls below one-half of one per

cent., and in each individual split falls below three-tenths of

one per cent., as shown by samples taken and duly analyzed,
: and such condition has been maintained continuously for a
period of not less than thirty days, the district mine inspector
may by written certificate authorize the rating of such mine,
during maintenance of such condition, as a non-gaseous mine.

Grounding means the establishment of an effective electric
connection between the object grounded and the earth, whether
the object grounded be a machine frame, a cable armor or an
electric system.

Live or Alive applies to any part of an electric system,
circuit, or apparatus or object in contact with or adjacent
thereto, charged with electricity or generating voltage to an
extent that the difference of potential between such system,
circuit, apparatus or object and the earth is measurable by a