THE MINERAL INDUSTRY OF IOWA 
321 
 
 Overall unit value of crushed and broken stone in 1967 was $1.44 per ton,
the~ same as in 1966. 
 Dimension limestone was produced from three quarries located in Dubuque,
Harrison, and Jones Counties. Production increased slightly in quantity and
13 percent in value over that of 1966. 
 Iowa became the first State to enact into law evaluation of agricultural
lime on an ECCE (Effective Calcium Carbonate Equivalent) basis. The method
of evaluation was initiated in 1965 by the Iowa State University in cooperation
with the Iowa Limestone Producers Association. The ECCE is a measure of the
effectiveness of a given quantity of lime generally expressed as "Certified__pounds
ECCE, per ton." Under Iowa's new law, the certification must be affixed to
every scale ticket or delivery receipt. The law was to become effective January
1, 1968. 
 
MINERAL FUELS 
 
 Coal (Bituminous).—Production of coal 
decreased 14 percent in quantity and 15 percent in total value. Average value
per ton decreased to $3.66 from $3.69. 
 One new mine was opened during the year, a strip mine operated by the Mich
Coal Co. in Mahaska County. Two mines closed in 1967; both were underground
operations, operated by the No. 4 Coal Co. and the Walter Coal Co~ in Appanoose
and Marion Counties, respectively. 
 Approximately 78 percent of the coal output from the State's five underground

and 12 strip mine operations was used in electric powerplants. Of the total
State production, over 70 percent was shipped to consumers by rail and the
remainder by truck. Approximately 64 percent of the 5.5 million tons of coal
consumed in Iowa in 1967 was supplied from Illinois mines; 16 percent was
furnished from mines within the State. 
 Coal seams mined in underground operations during the year ranged in thickness
from 32 to 70 inches. Thickness of coal seams mined in strip operations ranged
from 36 to 66 inches, with overburden ranging from 25 to 70 feet. No mechanical
cleaning plants were operated in the State in 1967. 
 
 Peat.—Production of peat increased approximately 4 percent in quantity
and 5 percent in value from that of 1966. 
 The Eli Colby Co. mined moss peat in Winnebago County near Lake Mills and
processed it at its plant in Hanlontown. The Colby Pioneer Peat Co. mined
reedsedge and humus peat from a deposit near Fertile in Worth County and
processed the material at its plant, also located in Hanlontown. The peat
was sold for general soil improvement, in bulk and packaged form. 
 
 Petroleum, Natural Gas.—No production of petroleum or natural gas
was reported. Exploration drilling reported by the American Association of
Petroleum Geologists consisted of one wildcat well, drilled in Washington
County to a depth of only 100 feet. It was a dry hole. 
 
Table 8.—Coal (bituminous) production in 1967, by counties 
 
(Excludes mines producing less than 1,000 short tons) 
County 
Number of mines 
 
operated 
Pro 
duction (short 
tons) 
Value 
 
Under- Strip ground 
Underground 
Strip 
Total 
 
Appanoose                    
Lucas                        
Mahaska                          
Marion                       
Monroe                      
Van Buren                         
 
Total                   
2         
1          
 71 41         1 
7,465 
100,901 
  
1,359 
185,093 
  
327,072 
248,775 
  
12,176 
7,465 
100,901 
327,072 
250,134 
185,093 
12,176 
$52,412 
361,516 
1,201,353 
903,047 
650,000 
59,058 
 
5 12 
294,818 
588,023 
882,841 
3,227,386