Geological Survey Bulletin 707 Guidebook of the Western United States: Part E. The Denver & Rio Grande Western Route

On leaving Malta for Leadville the railroad turns sharply to the east and winds about the gently rolling slopes of the valley side in order to get distance in which to make the ascent without climbing too steep a grade. At first the road winds up the slope among the pine trees, but farther on it comes out upon the edge of a terrace that overlooks a small ravine or "gulch,"³² as all such features are called in this region, and the traveler may look down upon one of the smelters which is engaged in extracting valuable metal from the ore that is mined in the famous Carbonate Hill, a picture of which is shown in Plate XLIX.

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³²This ravine is California Gulch, in which gold was first discovered in this region in 1859.

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PLATE XLIX. CARBONATE HILL, LEADVILLE. Out of the mines on this hill come some of the richest silver ore ever mined. It made fortunes for the operators in the early days and is yet yielding a large amount of precious metal. Recently the mine dumps have been reworked for zinc ore that was formerly discarded but during the war became very valuable. Mount Elbert, in the distance. Photograph by L. C. McClure, Denver.

Leadville is one of the highest towns in the world, standing 10,200 feet, or nearly 2 miles, above sea level. It is also one of the oldest towns of Colorado, dating back to 1860, the year in which the site of Denver was first occupied by white men. In 1859 gold is said to have been discovered in a little gulch that enters the Arkansas Valley from the east at the site of Malta by a party of gold seekers on their way to California, who on that account called it California Gulch. This discovery was made late in the autumn, and the party was not prepared to spend the winter there, so they left; but they returned the next year and established a mining camp which they christened Oro City (meaning Gold City) and which before the end of the year had a population of 5,000. Its fame spread, and in 1861 it was the most populous town in Colorado Territory. In a few years more than $5,000,000 had been washed from its golden sands, but like that of all other placer deposits the life of this one was ephemeral, for in a few years the town was nearly abandoned by the gold seekers, and for several years it played only a small part in the history of the mining region.

From 1874 to 1877 there was a revival of interest in the Leadville region, for silver-lead ores were found at several places in the vicinity of California Gulch, but no development was undertaken until 1878. Before that year the camp consisted of only a cluster of log cabins, but in 1878 a "rush" to the new workings began and the camp at once sprang into prominence as the greatest silver camp in the world. The Denver & Rio Grande Railroad was completed to the gulch in 1880, and the camp soon had a population of 30,000. During the first decade of its existence the silver and lead produced is reported to have been worth more than $120,000,000, Silver mining was the chief industry until the slump in the price of silver in 1893. For a time there was great stagnation, and then the miners turned their attention to the production of gold, silver, copper, lead, and zinc. In 1920 the value of the output of the mines of Lake County, which includes some mines outside the Leadville district, was $4,320,510. The total metallic output up to the end of 1920 is valued at a little more than $419,000,000.³³

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³³The following more detailed account of the history of the Leadville district is taken largely from the reports of Emmons and Irving (Geology and mining industry of Leadville, Colo.: U. S. Geol. Survey Mon. 12, 1886; The Downtown district of Leadville, Colo.: U. S. Geol. Survey Bull. 320, 1907).

During the summer of 1859, at the time of the great Pikes Peak excitement, a continuous stream of emigrant wagons stretched across the plains, following Arkansas River up to the base of Pikes Peak. Many of the wagons that had crossed the plains in the early summer, carrying the triumphant device "Pikes Peak or bust," returned later over the same route with the device significantly altered to the single word "Busted," but the more adventurous of these pioneers pushed resolutely up through the narrow rocky gorges toward the sources of the streams. Some wandered across the mountains during the same season into South Park and found gold-bearing gravel on Tarryall Creek and in the neighborhood of Fairplay.

Early in the spring of 1860 some of the prospectors found gold in the gravel at the site of the village of Granite, and others passed on to California Gulch, near the present station of Malta, where the most valuable discovery of the season was made. News of the finding of gold in this gulch spread with wonderful rapidity, and eager miners flocked in rapidly.

Large quantities of the precious metal were obtained from the gulch, and within a year the town that was built along its banks, known as Oro City, is said to have had 10,000 inhabitants. Estimates of the gold produced that year differ widely, some being as high as $10,000,000 and others as low as $3,000,000, but the rich placers were soon exhausted, and the population dwindled in three or four years to a few hundred, Some prospecting was done for the veins which supplied the gold of the placers, and several mines that gave a fitful gleam of prosperity to the camp were located, but the general feeling was one of pessimism and the settlement was practically deserted. The rich sliver-lead ores, which later were to give this region a world-wide reputation, were undiscovered, or rather unrecognized. The miners had gained most of their experience in the gold fields of California, and to these men silver ore was comparatively unknown and worthless. Few suspected the value of the so-called "heavy rock"—fragments of iron-stained carbonate of lead which obstructed their sluices and had to be thrown out by hand. Although later many claimed to have known of the rich silver-lead ores, their practical discovery was due to A. B. Wood, an experienced miner and metallurgist who came to the region in 1874.

Active prospecting over the entire region may be said to have commenced in the spring of 1877; and the development of rich and productive mines from that time on advanced with a rapidity that was truly marvelous. At the beginning of this era of prosperity the settlement consisted of a few log cabins on the edge of California Gulch, with an estimated population of 200; its business houses consisted of a "ten by twelve" grocery and two small saloons. The three mines were scarcely more than surface scratchings, and a lead furnace was planned but not erected. Communication was had with the outside world by stage or wagon, either across the crests of two high ranges to Denver or by an almost equally difficult road to Colorado Springs. In petitioning for a post office the names Cerusite (the mineralogical name for lead carbonate) and Agassiz were proposed but rejected as being too scientific, Lead City was suggested, but finally a compromise was reached on Leadville.

In 1880, three years later, the city of Leadville had 15,000 inhabitants, 28 miles of streets, and more than 5 miles of water mains and was in part lighted by gas. It had 1,100 pupils in daily attendance at its schools, five churches, three public hospitals, an opera house, six banks, and many business houses, constructed of brick and stone. Its assessable property is estimated to have been $30,000,000, and $1,400,000 was expended in 1880 in new buildings and improvements. To support this population there were over thirty producing mines and ten large smelting works, and the annual production of gold, silver, and lead amounted to $15,000,000.

This burst of development was continued until 1884, but since that year the district has maintained a fair degree of regularity, its average being a little more than $9,000,000 a year.

The value of the total yearly metallic output of the district from 1877 to and including 1917 is shown in figure 26. This diagram shows also the values of the different metals that make up the output. The total production, as shown by the diagram, is fairly regular, except for two marked depressions, one in 1897 and the other in 1908. The first of these depressions was due to a strike, which caused many of the mines to become flooded, and the second to the generally low price of the metals. One of the most striking features shown by the diagram is the remarkable increase in the value of the output of this district since 1902, with the exception of 1908, 1909, and 1910. This great increase in the total has been due largely to the marketing of great quantities of zinc. In 1915 the zinc amounted to $8,989,154 out of a total of $13,839,401.

FIGURE 26.—Mineral production of Lake County from 1877 to 1918, inclusive. (click on image for an enlargement in a new window)

Figure 26 shows the gradual decline in the production of silver from a maximum in 1880 and of lead from a maximum in 1881-82. It also shows that at first gold formed only a small percentage of the whole but that in 1893 it began to increase and that in 1900 it attained a maximum of $2,500,000, Since that time it has run fairly regularly at somewhat over $1,009,000 a year. Copper began to form a notable percentage of the total in 1889, but since that year the output has been very regular, its value amounting to about $500,000 a year. The production of zinc has become one of the spectacular features of the Leadville district. The production of this metal first became noticeable in the returns for 1896, and for a few years it was small. After 1901, however, it increased rapidly until in 1915 it was more than two-thirds of the total output of the district.

Thus Leadville, which began in 1860 as a gold camp, became in 1879 the greatest silver-lead district this country has ever produced and in 1915 became predominantly a zinc district.

The nature and occurrence of the ores of Leadville bear little resemblance to those of the Cripple Creek district, described on pages 47-51. At Cripple Creek the ores were probably deposited from waters that ascended from deep in the interior of the earth through fissures in the breccia that filled the throat of an old volcano. At Leadville the ores replace limestone, but they are closely associated with sheets of porphyry that were forced while molten in between the layers of limestone or between the limestone and adjacent quartzite. This relation is shown in figure 27, which represents a section through some of the workings. Whether or not the ores were brought to this place by waters ascending from great depth or by waters sinking down through cracks in the rocks from the surface has not ascending from great depth or by waters sinking down through cracks in the rocks from the surface has not been satisfactorily determined, but since the ores were originally deposited they have certainly been concentrated by what is called "enrichment"—that is, by the solution by surface waters of the disseminated ore and its redeposition at a lower level. The ores are generally most abundant beneath the layers or "sills" of porphyry, but they are found also in some places below the quartzite.

FIGURE 27.—Section through some of the workings at Leadville, showing the relation of the ore to the limestone, porphyry, and quartzite, wp, white porphyry; gp, gray porphyry; lvl, Leadville limestone; pq, parting quartzite; wl, white limestone; qtz, lower quartzite; gr, granite. The ore bodies are indicated by cross hatching. The straight heavy lines represent faults, and the arrows show the direction of movement.

The ores originally consisted of sulphides of the principal metals—lead, zinc, copper, iron, and probably silver—but the silver was so much disseminated that it has been difficult to detect. Geologic work in the district has shown that the ores were deposited after the intrusion of the gray porphyry into the limestone and before the rocks were broken by the faults shown in figure 26. After they were deposited in fissures and solution cavities in the limestone much of the overlying mantle of rock was removed, and the ores were brought within the zone of weathering by surface waters. When the sulphides were thus exposed to weathering they were dissolved, changed to carbonates and oxides, and redeposited by the descending surface waters in a rather narrow zone, which has yielded most of the ores mined up to the present time. The extreme richness of the silver ore mined when the camp was at the zenith of its fame was due to the fact that the silver was redeposited near the surface and was the first valuable mineral to be reached in most of the mines. Many of the mines are now working sulphide ores, which are much leaner than the carbonate and oxide ores of the early days. The great increase in the value of the zinc in 1915 was due both to an increase in the production of ore and to a great increase in the price of the metal. This increase in price led to the reworking of dump heaps for the zinc ore that had been thrown away in the earlier and more prodigal exploration of the ore bodies. It is perhaps fortunate that zinc was so nearly worthless in the early days, for that led to its conservation until the World War, when the demand for it was unprecedented.

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Leadville, like most other mining camps, was built around mills and mine dumps, and much of it is therefore not beautiful.

Any description of mining operations in a mountainous region like that surrounding Leadville, particularly of those of the early or prospecting stage, would be incomplete without mention of the humble burro (see Pl. L, A), that patient beast of burden which has been the prospector's constant companion in his lonely wanderings over these bleak ranges and his main dependence for the transportation of supplies while he has been driving tunnels in search of ore; which has carried lumber and other material for building mine works and even heavy machinery up the steep mountain trails.

PLATE L. A (left). THE PATIENT BURRO. The humble beast of burden that made possible the development of mines in parts of the West. In derision he has been called the "Rocky Mountain canary." B (middle). TUNNELS IN EAGLE RIVER CANYON. View on the eastbound track from a tunnel that pieces a spur of massive granite. The mining town of Gilman, on the rim of the canyon, is shown in the distance. Photograph furnished by the Denver & Rio Grande Western Railroad. C (right). EARTH EROSION COLUMNS. In a semiarid country ordinary earth becomes almost as enduring as solid rock. These columns are 30 feet high and are protected by the caps from rain. Photograph by W. T. Lee.