D. H. Browne — Phosphorus in Iron Mtn.. Mich. 299 



Aet. XXXII. — The distribution of Phosphorus in the Lud- 

 ington Mine, Iron Mountain, Michigan ; by David H. 

 Beowne. With Plates YIII-XIII. 



[Paper read before the American Institute of Mining Engineers at its New York 

 Meeting, February, 18S9.] 



One of the most difficult problems in the chemistry of iron 

 ore, and one, so far as I am aware, the solution of which has 

 never been attempted, has been the distribution, throughout the 

 vein, of Bessemer ore, and its relation to the formation of the 

 deposit. In those hematite mines in which both Bessemer and 

 non-Bessemer ores occur, the sorting of the ore, as it lies in 

 the deposit, becomes a problem of much economic as well as 

 scientific interest. It would seem from a superficial examina- 

 tion, or indeed from any examination not conducted for this 

 especial purpose, as if high and low phosphorus ores were 

 mixed in inextricable confusion ; and a mining chemist is very 

 apt to fall into a system of adventitious analyses, taking first- 

 class ore wherever he can find it, and overlooking its relation 

 to the formation and position of the vein. I hope that a few 

 notes, which I shall present on this subject, may be found worthy 

 of consideration, as throwing a new light on this obscure topic. 



During the last three years, while acting as chemist of the 

 Lumberman's Mining Co., I have made some 3000 analyses of 

 ore from the Ludington Mine, at Iron Mountain, Mich. These 

 analyses were necessary in order to separate Bessemer and 

 non-Bessemer ore which occurred intermixed in the deposit. 

 During the last year I attempted in several ways to find some 

 reason or method in the distribution of phosphorus ; and have 

 finally become cognizant of the arrangement herein outlined. 

 I have been obliged to confine my attention to one mine, and 

 of that, to that portion wherein the commercial quality of the 

 ore was such as to demand systematic sampling and analysis. 

 The analyses, therefore, and the conclusions drawn therefrom, 

 are given merely as facts found to exist, and I do not claim 

 that such sequence as I have noticed will obtain in all or every 

 case. I simply state what results I have obtained in an inves- 

 tigation carefully conducted, and I give some conclusions to- 

 ward which the data seem to lead. 



The Ludington mine, like most on the Menominee Range, 

 consists of several lenticular deposits of soft blue hematite. 

 These deposits are contained between clay slates, which con- 

 form with the Huronian strata represented in the district. 

 The main deposit is about 700 feet in length and perhaps 60 

 feet in width. It strikes 1ST. 75° W., pitches 45° west, and dips 

 from 70° to 80° N". The ore is a very rich, soft, friable, bluish- 



