30 CFR § 47.51
Requirement for an MSDS.
Operators must have an MSDS for each hazardous chemical which they produce or use. The MSDS may be in any medium, such as paper or electronic, that does not restrict availability.
(a) For each hazardous chemical produced at the mine, the operator
must prepare an MSDS, and update it with significant, new information about
the chemical's hazards or protective measures within 3 months of
becoming aware of this information.
(b) For each hazardous chemical brought to the mine, the operator must rely on the MSDS received from the chemical manufacturer or supplier, develop their own MSDS, or obtain one from another source.
(c) Although the operator is not responsible for an inaccurate MSDS obtained from the chemical's manufacturer, supplier, or other source, the operator must--
(1) Replace an outdated MSDS upon receipt of an updated revision,
(2) Obtain an accurate MSDS as soon as possible after becoming aware of an inaccuracy.
(d) The operator is not required to prepare an MSDS for an intermediate chemical or by-product resulting from mining or milling if its hazards are already addressed on the MSDS of the source chemical.