Last updated: 29 March, 2019 10:45
Stratton's Independence, Ltd.; December 2, 1911

The Engineering and Mining Journal, December 2, 1911
(page 1080)

Images used not part of source, but from my own collection.
Stratton's Independence, Ltd.

The report of Stratton's Independence, Ltd., for the year ended June 30, 1911, shows that the net profit for the year was £21,000, of which sum £12,500 were paid out as a dividend. Development work to the extent of 9186 ft. was done in the mine, of which 19 per cent, was in the form of crosscutting.

Independence Mine and Mill, Cripple Creek District.
A later view at the immense
Independence Mine and Mill complex.

According to the consulting engineers, Philip Argall & Sons, by far the greater part of the ore discovered during the year is the result of this persistent crosscutting. On the surface, while the same number of lessees was working, the majority of them worked on a small scale. All surface leases are now limited to 50-ft. depth, and all the ground between that depth and the 100-ft. level is to be worked from the new "A" level.

The "A" level was started in February, 1911, to develop the ground between the 100-ft. level and the surface and at the same time to obtain waste rock to fill the old stopes of the mine. There is still a great quantity of ore in the old workings, which cannot be reached until the stopes are filled and made safe, so that in driving this "A" level through the caved ground it will be possible to drop a quantity of waste into stopes that are particularly dangerous in their present unsupported condition.

Machine Mining in Colorado.
Underground Scene at unidentified Mine.

A raise was put up from the 100-ft. level at a point 150 ft. north of the shaft and ore was found. The level was then started both ways, north and south, on ore in the north end; the ore continued for 125 ft. before barren ground was struck. Superintendent Johnson believes that when the "A" level is completed to the north end line of the property and is thoroughly prospected, it will be one of the best producing levels in the mine, and it will do away with all surface leasing.

The drainage tunnel had not relieved the water situation to any great extent, the water having receded only 50 ft. during the year.

In addition to ore of shipping grade the company for the first time produced low-grade milling ore amounting to 7440 tons. The greater part of this was sorted out of the ore rejected by the lessees and sent direct to the mine breaker, while the waste went back into the mine for filling.

Formerly both products, the low-grade milling ore and the waste, went to build up the ore-house dump. Now everything that passes through the ore house is worked up daily and finally disposed of. The total production of the mine was 25,825 tons, having a gross value of $534,068 and a value of $389,008, after deducting freight and treatment charges.

The mine breaker and roll mill began operations in October, 1910, and averaged about 825 tons per month during the nine months of the fiscal year in which the plant was in operation.

In addition to the changes required to combine the wet mill with the mine breaker and roll mill, the permanent breaker plant of 70 tons per hour capacity was erected in the clearing made in the heart of the dump by previous milling operations.

The fourth Chilean mill was erected as a reserve, and six more slime tables added, together with new distributers and a new settling tank in the cyanide department. These additions brought up the milling capacity from 7500 tons per month to 10,000 per month, an increase of 33 per cent.

The sum of £13,900 was charged to mill construction during the year. The 109,800 tons of ore milled during the year averaged 0.157 oz. per ton. The total recovery was 71.5 per cent.; 43.65 per cent, by concentration and 27.85 per cent, by cyaniding.

The total milling cost is given as $1.52 per ton, which agrees closely with Philip Argall's estimate made in 1907 as to the probable cost on a basis of 10,000 tons per month with 70 per cent, extraction.


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