MSHA Regulations. Subchapter H - Education and Training. Part 46 - Training and Retraining of Miners Engaged in Shell Dredging or Employed at Sand, Gravel, Surface Stone, Surface Clay, Colloidal Phosphate, or Surface Limestone Mines. Data is current as of October 1, 2018. Authority. §46. 1 - Scope. §46. 2 - Definitions. §46. 3 - Training plans. §46.