Class Code: 1701
Per NCCI's Scopes Code Description:
Code 1701 is applied to employers that manufacture cement. The raw materials (limestone, marl, alumina, lime, iron oxide, and magnesia) are received, crushed, blended, and sized in rock crushing, rough milling, and screening equipment. The material is ground by either a wet or dry process but largely in ball or tube mills followed by blending in proportioning equipment. Very large, continuous rotary kilns are generally used. The final process is finish-grinding prior to storing in silos or sacking in paper bags.
This classification also applies to employers that manufacture plaster. Limestone received from outside sources is repeatedly crushed. Water and moisture are removed by calcinating in high heat by either the batch process in kettles or by continuous roll on conveyors. When dried, the milled limestone is again ground and mixed with gypsum, sand, expanded perlite, retarders, stabilizers, and wood fibers, depending upon the type of plaster being manufactured. The final product is packaged in heavy bags
Code 1701 also applies to employers that grind silica or minerals which contain a substantial proportion of pure silica such as quartz, sand, sandstone, chalcedony, flint, tripoli, and diatomaceous earth. The raw material is received at the grinding mill for final sizing. This classification includes secondary crushing and grinding to a fine powder in machinery that today is generally fully enclosed to control the fine dust. Code 1701 also covers mica grinding, slate grinding, and roofing granules manufacturing.
In addition, Code 1701 applies to the manufacture of pressed mica products or sheet mica. Book mica or mica that has been partially split is received and split to a desired thickness using hand knives or knives mounted on tables. The split mica is then sent to punch presses that stamp out the various products usually utilized by the electrical trades. Mica which is too small to be processed on punch presses may be placed in burling machines, mixed with a liquid solution, and then pressed into sheets. The removal of imperfections or the application of mica to the sheets to obtain the required thickness is usually done by hand. These sheets are then dried, baked in ovens, and run through sanders prior to crating and shipping.
Massachusetts Refer to Code 1624 for the grinding of Silica, Flint or Spar. Refer to Code 1853 for Mica Goods Mfg. & Mica Preparing.