# The Coal and Other Mines (Locomotives) Order 1956, Paragraph 31


(1) The manager of every mine in which any diesel locomotive runs shall make and secure the efficient carrying out of arrangements whereby samples are taken by a competent person appointed for that purpose by him and analysed in accordance with the following provisions of this regulation.
(2) At intervals not exceeding ninety days separate samples of the gas emitted from the exhaust of every diesel locomotive in use in the mine shall be taken when the engine of the locomotive is—
(a) developing maximum power; and
(b) idling with the locomotive stationary.
(3) At intervals not exceeding thirty days separate samples of the general body of the air shall be taken at places and times appointed by the manager so as to secure the detection of any harmful concentration of carbon monoxide produced by any diesel locomotive. An inspector may by notice served on the manager require him to appoint any place specified in the notice either instead of or in addition to any place already appointed by the manager.
(4) Every sample taken in pursuance of paragraph (2) of this regulation shall within four days of the taking thereof be analysed to determine the percentages of carbon monoxide and oxides of nitrogen therein and every sample taken in pursuance of paragraph (3) of this regulation shall within that period be analysed to determine the percentage of carbon monoxide therein and particulars of each such analysis shall be recorded forthwith in a book provided for that purpose by the owner of the mine. In reckoning a period of four days for the purposes of this paragraph no account shall be taken of any Saturday, Sunday or day of general holiday.

---
Source: https://www.legislation.gov.uk/uksi/1956/1771/schedule/FIRST/paragraph/31 (the official version)
Page: https://openlegislation.uk/coal-and-other-mines-locomotives-order-1956/schedule-FIRST/paragraph-31
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.