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Subchapter 17. Mine Safety Orders
Article 16. Drilling Operations and Jumbos
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§7007. Jumbos--Construction and Use.

(a) Jumbo working platforms that are 30 inches or more in height shall be equipped with standard railings on open ends and sides, except where standard railings interfere with drilling operations, in which case they shall be provided with some other means of protection acceptable to the Division.

(b) Toeboards at least 4 inches high shall be provided around platforms of jumbos to prevent tools or other equipment from falling off.

(c) (7-8) Where drill steel is kept on jumbo platforms prior to or after use, suitable receptacles, such as boxes, racks, grooves, or equivalent, shall be provided for temporary storage.

(d) (7-8) No tools, materials, equipment, or other unattached objects shall remain on any platform while the jumbo is being moved, if any part of such protrudes beyond the width of the jumbo.

(e) (7-8) A safe means of access shall be provided to all jumbo platforms. Safe access may consist of a ramp, stair, or ladder constructed in compliance with the standards set forth in the General Industry Safety Orders.

(f) Where necessary, overhead protection against falling rock shall be provided at jumbo working areas.

(g) If bore holes are loaded from the jumbo, all electrical circuits to the jumbo shall be disconnected and the live ends removed to a minimum distance of 100 feet from the jumbo before explosives are brought to the heading.

(h) Warning must be given to men working below before starting to collar holes.

(i) When drill steel is hoisted by a power method, double slings with a tag line shall be used, or some other equally safe method shall be provided.

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