94 ILLINOIS ACADEMY OF SCIENCE 



has free pyrite most commonly in the form of nodules of 

 brassy, mettalic-like, massive sulphide. No. 5 coal in the 

 Peoria-Springfield district has pyrite balls of the same sore 

 in the npx^er coal, but more characteristic is what is known 

 as the brown or gray sulphur lenses. These are lenticular 

 or irregular masses of banded stony pyrite that finger later- 

 ally into the coal. No. 6 coals is distinctly a bedded coal, 

 separated into three or more persistent benches. The py- 

 rite is most commonly found as plates or thin lenses in the 

 parting between the benches. No.7 coal carries a large 

 amount of pyrite as irregular lenses of massive stony sul- 

 phide much like that found in No. 5 coal, but not commonly 

 banded. 



Pyrite can be recovered in two places : at the coal face 

 by the miner and loader, and at the tipple by pickers, by 

 mechanical dry separation, and by wasliing the coal. The 

 latter method is probably the most efficient, but the coal 

 should also be picked at the face to remove the large pyrite 

 nodules, if the pyrite is to be marketed. 



The ease of recoverability of tlie different forms of pyrite 

 varies. The more easily the pyrite can be recovered the 

 cleaner the coal that can be produced without special facil- 

 ities for treatment at the tipple. Large nodules of bright 

 pyrite such as are found in No. 2 coal are easily seen by the 

 miner, and relatively easiery removed. Irregular lenticu- 

 lar masses "frozen" to the coal, such as are found in No. 5 

 and No. 7 coals, are not readily removed, and the miner ^3 

 too inclined to throw chunks of coal containing such lenses 

 into tlie car, risking possible discovery at the tipple, and 

 the resulting fine. Too frequently this is a very slight 

 I'isk. Sheet pyrite is easily hand-picked when thicl?i 

 enough to resist the shattering incident to mining. When 

 thin, however, it breaks into small pieces and forms accord- 

 ingly a considerable part of the fine coal or screenings and 

 can only be removed by mechanical separation of some sort. 



If pyrite is to be considered as an impurity to be dis- 

 carded rather than a commodity to l)e saved, as a])parently 

 it must continue to ])e regarded until its recovery becomes 

 a matter of economic importance, the investigations have 

 indicated that more systematic efforts than have been in 



