weighing 1,141 pounds, value $20,000; one weighing 400 pounds, value $7,000; one 933 pounds, value $1,027; and one 113 pounds, value $1,625. The first two were from the Brown Company, the third from the Terrible mine and the last from 43 tons of Snowdrift ore.

The following is a list of the ores exhibited, together with their mill or assay values:


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All coin values, per ton of 2,000 pounds.

Sweepstakes lode, assay.

Peruvian lode, mill run.

Gilpin lode, mill run..

Ni-Wot lode, assay.

Griffith lode, assay.

Guthrie lode, mill run.

New Boston lode, assay, (50 per cent. lead).

Terrible lode, mill run

Lake Superior lode, assay

Magnet lode, mill run...

Mammoth lode, assay.

Brown lode, mill run.

Quaker lode, mill run.
Franklin lode, mill run
Astor lode, assay

Mendota lode, assay

Robert Emmett lode, mill run..

Bunker Hill lode, assay.

E Pluribus Unum lode, assay.

General Jackson lode, assay

Cashier lode, mill run...

Federal lode, select specimens, assay

Federal lode, second class, assay.

O K lode, mill run.....

Dives lode, assay

$440 00

513 80

120 00

400 00

120 00

728 00

30 00

650 00

146 00

320 00

500 00

650 00

200 00

96 00

400 00

260 00

179 10

800 00

1,000 00

200 00

230 00

27,000 00 800 00 1, 176 00

646 00

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Of course these figures do not represent the average yield of the ores: treated, still less the average value of the vein-material. Nor would the true average mill-yield give a direct measure of the general quality of ore. A common error with American miners has been the habitual, though often innocent, exaggeration of the "average value" of ores. People do not seem to know what this phrase means. At first it used to mean the average result of a large number of sample assays; then, when we had grown wiser, it meant the average of pulp assays taken in the mills; and beyond the latter signification we have apparently not yet advanced.

Now any district can maintain a high "average value" of this sort, as long as it sends only good ores to the mill or furnace; and the figures signify, not the average value of all the ore in the veins, not even that of the ore extracted, but that of the ore treated. In other words, they are a criterion of the expense of mining and reduction, and that is all. Moreover, since no mines ever did or do contain rich ores only, the high yields are generally associated with wasteful sorting, which still further increases the expense of mining.

Let him who would apply this test to a mine or a district measure the excavations on the lodes, calculate the whole amount of vein-matter removed, and compare this with the total of bullion produced. In Colorado this style of calculation would produce some surprising results. But Colorado is no worse and no better than any other districts in this respect. She is just now working her best mines, and of these only the best and second-best ores. When, in the progress of healthful industry, more mines shall be opened, existing mines operated on a larger scale and more permanent system, and less ore thrown away or left standing as too poor to work, we shall see an apparent decrease in the value per ton of the contents of her veins; and I cannot wish her better fortune than just this decrease.

In a subsequent chapter the processes of reduction employed in Colo. rado will be fully discussed, and more exact information as to average value and yield will be given.

H. Ex. 10-19


The Denver News estimates the total gold and silver yield of the Ter ritory for 1870, as follows:

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I am obliged to regard this estimate as altogether too high. The article which contained it showed the manner in which each item was calculated; and a revision of the whole, with additional sources of information, for which I am indebted to Mr. Schirmer of the Denver mint, and Mr. Jones, agent of Wells, Fargo & Co. at that place, leads me to substitute the following estimate, as the most accurate which I can obtain :

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The items of northern and southern mines in these estimates refer to the fact that much of the gold gathered in the mines of Park, Lake, and Summit Counties goes out, by the way of Colorado and Cañon Cities, to Pueblo, and thence east without coming to Denver at all. So of the product of the North Park, Snake, and White River mines in Northern and Northwestern Colorado. It finds its way to the line of the Union Pacific Railroad and thence east or west.

The deposits at the Denver branch mint were as follows:

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In the last six months of the year there were 1,144 deposits, of the value of $586,249 93, showing a very gratifying increase in both number and amount.

The following altitudes of noted localities, mostly within the Territory of Colorado, are taken from a pamphlet published by Colonel Baker of Central City. There are differences of a few feet in the determinations of many of these points. Thus, Denver, according to another good authority, has an altitude of 5,387 feet, which may easily be accounted for by supposing the observation to have been taken on the higher part of the town. Since, a third determination, made on the lower bottom of the Platte, at Denver, near the mouth of Cherry Creek, gives 5,303 feet only. Again, Georgetown is sometimes placed at 8,906 feet, a serious difference; and the Berthoud Pass at 11,562 feet, or 213 feet higher than in the table below. In a number of instances, Frémont's original hypsometrical determinations are given for comparison with more. modern ones.

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Divide between Arkansas and Platte, on road from Colorado City to Denver..

6, 342 7,554

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North branch of South Platte, Denver and Buckskin road

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10, 041

9, 842

9, 932

Three miles lower down

Junction, North and South Clear Creeks

Idaho, (12 feet above South Clear Creek)
Head of Virginia Cañon...

Where the Tarryall road leaves or strikes Fontaine qui Bouille.

8, 151

8, 273




Consolidated Ditch Office, (Missouri City)

Mouth of Fall River....

Level of Clear Creek at Empire City.
Base of Berthoud's Pass..

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13, 402

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13, 456


13, 223


Pike's Peak.

Pike's Peak, (Frémont)..

14, 216

Gray's Peak, (Argentine district)


Parry's Peak, (northwest of Empire City, named by General Case)
Mt. Flora, (a detached peak east of Parry's Peak).

14, 251

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Three-fourths of a mile from summit of Berthoud's Pass, (western slope)
Head of Middle Park.

Hot Springs of Grand River, 25 miles from head of Park


10, 696

8, 690


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These formidable altitudes are indications of the difficulty of intercommunication between the different mining districts. Yet the enterprise and skill of American engineers are not to be baffled by such obstacles; and it is safe to predict that railway communication, in some form, will, ere long, be extended into the heart of the mountains, to say nothing of the plans of sanguine projectors, who talk already of penetrating, by this line, to the Salt Lake Valley itself. At present there are three railroads centering at Denver: the Kansas Pacific, coming from Kansas City, the Denver Pacific, connecting with the Union Pacific at Cheyenne, and the Colorado Central, which strikes from Denver into the mountains. The latter road has been completed to Golden City, a distance of about fifteen miles, and was opened for business with appropriate festivities on the 24th of September, 1870. Another road, called the Boulder Valley Railroad, is in process of construction from a point on the Denver Pacific, about twenty-five miles north of Denver, to the Boulder coal-fields.

It is proposed to continue the Colorado Central to Central City or Georgetown, and some preliminary work has been done in Clear Creek Cañon. But the question of gauge, which has been considerably discussed, still remains unsettled. The narrow gauge, which has been employed with excellent economical results in India, Canada, Norway, and elsewhere, would be, it seems to me, just the thing for mountain branch roads, on account of its superior cheapness in construction and operation; but it appears difficult for the Colorado people to give up the idea of a great transcontinental trunk-line. The ambition of the powerful Kansas Pacific Company seems to point in this direction. A narrow-gauge line beyond Golden City, necessitating transshipments at that place, would be a great local advantage to it, while the continuance of the ordinary gauge to Central and Georgetown would be better for those localities, if its construction and successful operation were feasible. My impression is that Gilpin and Clear Creek Counties will have to choose between the narrow gauge and nothing. Meanwhile, a bold and, perhaps, visionary scheme is said to be connected with the Boulder Valley line. I quote the following statement from a letter to the New York Tribune:

The Kansas Pacific is a powerful corporation, and, properly, it is the line by which the Cotton States are to communicate with California and China; but, unfortunately,

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