1917] Forbes: Irrigation Effects of Copper Compounds Upon Crops 405 



copper in ores, tailings, waters, soils, and organic materials, is 

 to be found under "Methods of Analysis" in the appendix to 

 this paper. For convenience in comparing widely variable 

 amounts in the samples examined, the copper content is given in 

 parts per million of substance. Parts per million may be reduced 

 to percentages by moving the decimal point four places to the 

 left. For instance, 11,600 parts per million is equal to 1.16 

 per cent. 



TABLE II 



Copper in Ores and Tailings from the Clifton-Morenci Mining District 



Cu 



parts 



per 



million 



Sample No. 

 and date 



3491 



May 23, '04 



3303 

 May 23, '04 



3438 

 June 28, '05 



3499 

 June 28, '05 



D. C. Co.'s 



Records 

 May 20, '04 



3492 

 May 23, '04 



3304 

 May 23, '04 



. 3439 

 June 28, '05 



3500 

 June 27, '05 



3309 

 May 26, '04 



3486 

 June 11, '05 



3737 

 Feb. 22, '07 



6342 

 Mar. 4, '16 



Description of sample 

 One day 's run of sulphide ore from 



from A. C. Co.'s mill in Clifton 

 Sulphide tailings, point of discharge 



from A. C. Co. 's mill, Clifton 

 Sulphide tailings, point of discharge 



from A. C. Co.'s mill, Clifton 

 Sulphide tailings at Clifton coming 



from Longfellow mill 



Fine sulphide tailings at Morenci 



One day 's run of oxidized ore from 

 A. C. Co.'s mill at Clifton 



Oxidized tailings, point of discharge 

 from A. C. Co. 's mill, Clifton 



Oxidized tailings, point of discharge 

 from A. C. Co.'s mill, Clifton 



Oxidized tailings, point of discharge 

 from Shannon C. Co. 's mill, Clifton 



Milky sediments, pure tailings from 

 Montezuma Canal, Solomonville 



River sediments with tailings from 

 Montezuma Canal, Solomonville 



High river sediments with muddy 

 tailings from Montezuma Canal, 

 Solomonville 



Floodwater sediments from Monte- 

 zuma Canal, Solomonville; tail- 

 ings from Mogollon 



Condition and 



weight taken, 



grams 



1 



air-dry 



1 



water-free 



1 

 water-free 



1 

 water-free 



1 

 air-dry 



1 



water-free 



1 

 water-free 



1 

 water-free 



2 

 water-free 



2 

 water-free 



15.8 

 water-free 



.5899 



Cu 

 found, 

 grams 



.03195 

 .00935 

 .0116 

 .00725 



.0553 



.0225 



.0268 



.0114 



.01725 



.0067 



trace 



.000085 



31,950 

 9,350 



11,600 

 7,250 



10,000 



55,300 

 25,500 

 26,800 

 11,400 

 8,625 

 3,350 



trace 



53 



A point of interest to both mine owners and farmers in table 

 II is the large proportion of copper that was discarded with 

 tailings at the time the samples were taken. This loss, so far as 

 these figures show, may amount to almost one-third of the copper 



