THE MINERAL INDUSTRY OF MINNESOTATable 4.—Employment and injury experience
in the mineral industries 
431 
Year and industry 
Average 
men 
working 
daily 
Days 
Active 
Man- 
days 
worked 
(thou- 
sands) 
Man- Number of hours injuries worked 
(thou- Fatal Non- 
sands) fatal 
Injury rates per million man-hours 
 
Fre- Severity quency 
1966: 
 
 
 
 
 
Peat                
25 
112 
3 
19 
 
Metal                 
Nonmetal              
Sand and gravel         
Stone                  
 Total 1              1967: P 
10,008 
219 
2,265 
1,452 
294 
271 
181 
259 
2,937 
59 
409 
376 
 23,521 4 97 478 1 29 3,553 2 62 
3,116.. 47 
4.29 1,28362.74 14,94018.01 3,84415.08 391 
 
13,964 
271 
3,784 
 30,688 7 235 
7.89 1,701 
 
 
 
 
 
 
Peat                  
30 
115 
3 
25 1 
39.70 397 
Metal                 
Nonmetal              
Sand and gravel         
Stone                  
 
Total'               
9,340 
210 
2,190 
1,315 
295 
261 
172 
263 
2,752 
54 
377 
346 
 22,026 6 71 436  21 3,382 1 53 2,828  47 
3.50 2,10248.16 2,03215.97 2,27916.62 489 
 
13,080 
270 
3,532 
 28,698 7 193 
6.97 1,961 
P Preliminary. 
Data may not add to totals shown because of independent rounding. 
 
REVIEW BY MINERAL COMMODITIES 
METALS 
 
 Copper-Nickel.—Copper-nickel exploration continued along the Duluth
Gabbro in Cook, Lake, and St. Louis Counties. Major companies holding leases
in the area and! or doing exploration work included: 
American Metal Climax, Inc., Bear Creek Mining Co. (exploration division
of Kennecott Copper Corp.), Canadian Mining & Smelting Ltd., Cleveland-Cliffs
Iron Co., Duval Corp., The Hanna Mining Co., Humble Oil & Refining Co.,
The International Nickel Co., Inc., Newmont Exploration Ltd., The New jersey
Zinc Co., United States Steel Corp., and Phelps Dodge Corp. 
 The International Nickel Co., Inc. (Inco), began sinking a 1,100-foot exploration
shaft along the South Kawishiwi River, southeast of Ely. In 1968 the company
planned to mine from lateral development a bulk sample for metallurgical
testing at its Copper Cliff, Ontario, plant. Inco also conducted diamond
drilling on its leases in the area. Legislation was enacted by the 1967 Minnesota
Legislature establishing the State income tax as the basic method of taxation
for copper-nickel mining. A production tax was also placed on the copper-nickel
output in lieu of ad valorem property taxes. 
 The Minnesota Geological Survey conducted geological mapping, geophysical
investigations, and other research on the 
Duluth Gabbro Complex and its coppernickel deposits. 
 The University of Minnesota Mines Experiment Station studied flotation processes
for the' concentration of copper-nickel ores. 
 
 Iron Ore.—Shipments of usable iron ore (excluding ore containing 5
percent or more manganese, natural) from Minnesota mines were 49.5 million
long tons, a decrease of 10 percent from that of 1966. Value of mine shipments
was $468.6 million, 6 percent less than in 1966. The lesser decrease in value
resulted from a combination of an 11-percent increase in shipments of higher
value taconite concentrates and a 24-percent decrease in natural ore shipments.
Concentrates constituted about 77 percent of the total iron ore shipped in
1967. Average iron content of usable ore was 57.3 percent, compared with
56.4 percent in 1966. 
 Lake Erie base prices for iron ore remained unchanged from 1966. As the
result of taconite pellets representing a larger share of the total iron
ore shipments, the 1967 average weighted mine value of Minnesota iron ore
increased to $9.48 per ton compared with $9.06 per ton in 1966. 
 Nearly all iron ore produced in Minnesota was sold for pig iron and steel
manufacturing. Small quantities were sold for cement manufacture and foundry
purposes.