Mine detail: Maas Mine

Previously called 'Race Course'

Location:	Marquette County, Michigan, United States, North America
Lat / long:	46.50944, -87.59808
dep_id:	10082753
mrds_id:	W062103
Commodity type:	metallic
Major mineral:	Iron
Operation type:	Unknown
Deposit type:	Bedded, Chemical Sediment
Production size:	Medium ammount of material produced
Development status:	Past Producer
ore:	Hematite, Magnetite, Goethite
gangue:	Quartz
orebody_fm:	STRATABOUND
work_type:	Underground
model:	241: Superior Fe (BC name is Lake Superior & Rapitan types iron-formation)
alteration:	Some magnetite formed by replacement of ferrous iron minerals during diagenesis and most iron silicate probably formed by metamorphism of an early silicate mineral.
conc_proc:	Soft ore formed during the mid to late Proterozoic and/or possibly as young as the Cretaceous by (1) interaction of supergene groundwater which caused oxidation of ferrous iron minerals (siderite), (2) leaching of chert and its replacement by secondary hematite and goethite, and (3) removal of large amounts of CO2. hard ore formed by oxidation of carbonate of iron formation to soft ore during a period of mid-Proterozoic weathering and metamorphism during the Penokean orogeny which caused the soft ore to recrystallize to hard ore.
Reporter:	Sutphin, D.M. (Cannon, W.F.), Mason Jr., G.T.
hrock_unit:	Negaunee Iron-Formation
hrock_type:	Iron Formation
Structure:	Westward plunging synclinorium open at western end; regional trends are eas
Year first produced:	1907
disc_yr:	1844
prod_yrs:	SHIPPED ORE EVERY YEAR 1907-1950. WAS ACTIVE 1907-1967. STOCKPILE SHIPMENTS ONLY WERE MADE IN 1967.
discr:	George Maas
References:	Deposit:: JAMES, H. L., 1955, ZONES REG. METAMORPHISM. IN N. MICHIGAN.: GEOLOGICAL SOCIETY OF AMERICAN BULLETIN, V. 66, P. 1455-1488. Deposit:: THE LAKE SUPERIOR IRON ASSOC., 1938, LAKE SUPERIOR IRON ORES. Deposit:: LAKE SUPERIOR IRON ORE ASSOCIATION, 1952, LAKE SUPERIOR IRON ORES: CLEVELAND, OHIO, 2D ED., 334 P. Deposit:: GRATON-SALES VOL. A. I. M. E., THE MARQUETTE DISTRICT: ORE DEPOSITS OF THE U. S., 1933-1967, P. 508-517. Deposit:: LAURA, D.K., 1981, THE EARLY PROTEROZOIC PRE-IRON FORMATION, MENOMINEE GROUP SILICICLASTIC SEDIMENTS OF THE SOUTHERN LAKE SUPERIOR REGION; EVIDENCE FOR SEDIMENTATION IN PLATFORM AND BASINAL SETTINGS: JOURNAL OF SEDIMENTARY PETROLOGY, V. 51, NO. 2, P. 397-414. Deposit:: SIMS, P.K., 1990, GEOLOGIC MAP OF THE PRECAMBRIAN ROCKS OF IRON MOUNTAIN AND ESCANABA 1 DEGREE X 2 DEGREES QUADRANGLES, NORTHEASTERN WISCONSIN AND NORTHWESTERN MICHIGAN: U.S. GEOLOGICAL SURVEY MISCELLANEOUS INVESTIGATION SERIES, I-2056. Deposit:: BOYUM, B.H. AND REED, R.C., 1988, MARQUETTE MINERAL DISTRICT OF MICHIGAN, MINING HISTORY AND GEOLOGY, IN SCHULZ, K.J., 34TH ANNUAL INSTITUTE ON LAKE SUPERIOR GEOLOGY FIELD TRIP GUIDEBOOKS, V. 34, PART 2, P. B-1-B-15. Deposit:: BOYUM, B.H., 1988, THE ORIGIN AND EXTENT OF THE HARD AND SOFT IRON ORES OF THE MARQUETTE RANGE, MICHIGAN, IN KISVARSANYI, GEZA, AND GRANT, S.K., NORTH AMERICAN CONFERENCE ON TECTONIC CONTROL OF ORE DEPOSITS AND THE VERTICAL AND HORIZONTAL EXTENT OF ORE SYSTEMS, PROCEEDINGS VOLUME: UNIVERSITY OF MISSOURI, ROLLA, P. 301-311. Deposit:: PUFFETT, 1974,: U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 788. Deposit:: MOST ALL OF THIS DISTRICT HAS BEEN MAPPED AT 7 1/2 MINUTE QUADRANGLE SIZE. TOO MANY GEOLOGISTS HAVE BEEN INVOLVED TO MENTION INDIVIDUALLY. GAIR, J.E., 1975, BEDROCK GEOLOGY AND ORE DEPOSITS OF THE PALMER QUADRANGLE, MARQUETTE COUNTY, MICHIGAN: U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 769, 159 P. Production:: LAKE SUPERIOR IRON ORE ASSOCIATION, 1952, LAKE SUPERIOR IRON ORES: CLEVELAND, OHIO, 2D ED., 75-92 P. PUFFETT, 1974, P. 48.