Code 1452 “Ore Milling & Drivers,” Code 1430 “Smelting, Sintering or Refining Lead & Drivers,” and Code 1438  shall not be assigned to the same risk unless the operations described by these classifications are conducted as separate and distinct businesses.

Code 1452  applies to employers engaged in processing raw ores that are received from mines.  Processing includes crushing, concentration or amalgamation.  Ores are fed into crushers and then ball mills which reduce the ore to a powder.  The powder producing an ore is screened and may first be treated with caustic materials or acids.  The powder then goes through a flotation process where it is mixed with water slurry which passes over gravity separators causing lighter rock to wash away and the heavier ores to sink.  The ore slurry is then treated with various chemicals that separate different ores from others.  Most metal ores, when mined, contain other metals that can be separated in this manner.  

Segregated ore slurries are heated to remove excess water.  The slurry may then be pressed into pellets or just dried in rotary kilns.  This is known as the concentration process.  

Different ore concentrates may be mixed together (amalgamates) prior to shipment to customers.  

The manufacturing of natural graphite, i.e., the extraction of graphite from graphite rock, is also included under this classification.  This process involves crushing, milling, pulverizing, screening, floatation and lastly drying.   

The milling of ores to recover some nonmetallic minerals which do not require amalgamation or floatation also falls within this classification.  

This classification also includes employers that are engaged in phosphate works.  Phosphate rock or phosphate pebbles are received from others.  The process starts with running the phosphate rocks or pebbles through a washer which removes mud and sand.  The rocks and pebbles are then crushed, ground, screened and washed.  The material is then dried in dryers and is either bagged or shipped in bulk to the employer’s customers which are usually wet-mixing fertilizer plants.   

This classification contemplates the treatment of ground phosphate pebbles or rock with sulphuric, phosphoric or nitric acids.  These acids may be received from others or manufactured by the employer provided that the acids are used solely in production of their own product.  Decomposing ground phosphate with acids produces a product, i.e., acid phosphate or super phosphate.  This type of product when prepared is typically shipped to dry-mixing plants for use in the preparation of complete fertilizers.