share of the whole district for some years past has been practically
four-fifths of the total output of the country; and together with
the yield of the southern district, more than 90%. Minnesota
alone produces more than half of the same total, having multiplied
her product since 1889 by more than 33 times. Michigan held
first place in output until 1901. Alabama is the third great producer
of the Union, and with the other two made up in 1907 more
than four-fifths of the country's total. In 1907 the product of
Minnesota (28,969,658 long tons) was greater than that of
Germany (with Luxemburg), and nearly twice the production of Great
Britain.
Of the two classes of iron minerals used as ores of that metal, namely, oxides and carbonates, the latter furnish to-day an insignificant proportion of the country's product, although such ores were the basis of a considerable part of the early iron industry, and even so late as 1889 represented one-thirteenth of the total. Of the oxides, various forms of the brown ores in locations near to the Atlantic coast were the chief basis of the early iron industries. Magnetites were also early employed, at first in Catalan forges, in which by means of a direct process the metal was secured from the ores and forged into blooms without being cast; later they were smelted in blast furnaces. But in the recent and great development of the iron industry the red haematite ores have been overwhelmingly predominant. From 1889 to 1907 the average yearly percentages of the red haematite, brown ores, magnetite and carbonate in the total ore production were respectively 82.4, 10.1, 7.1 and 0.4. In the census of 1870 the share of the three varieties appeared almost equal; in 1899 that of the red ores had risen to near two-thirds of the total. The red and brown ores are widely distributed, every state in the Union in 1907, save Ohio and North Carolina, producing one or both. Magnetite production was confined to mountain regions in the east and west, and only in Ohio were carbonates mined.
An investigation was made in 1908 for the National Conservation Commission of the ore reserves of the country. This report was made by Dr. C. W. Hayes of the Geological Survey. With the reservations that only in the case of certain red haematite bedded deposits can any estimate be made of relative accuracy, say within 10%; that the concentration deposits of brown ore can be estimated only with an accuracy represented by a factor varying between 0.7 and 3; and that the great Lake Superior and the less known Adirondack deposits can be estimated within 15 to 20%, the total supply of the country was estimated at 79,594,220,000 long tons—73,210,415,000 of which were credited to haematite ores and 5,054,675,000 to magnetite. Almost 95% is believed to lie about Lake Superior.
The output of pig iron and steel in 1907 was 25,781,361 and 23,362,594 long tons respectively. It is believed that the first steel made in the United States was made in Connecticut in 1728. Crucible steel was first successfully produced in 1832, Bessemer and open-hearth in 1864. Pennsylvania, Ohio, Illinois, Alabama and New York are the leading states in production.
The washing of the high or Tertiary gravels by the hydraulic process and the working of mines in the solid rock did not, on the Gold and Silver. whole, compensate for the diminished yield of the ordinary placer and river diggings, so that the product of gold in California continued to fall off, and by 1860 had decreased to about half what it had been ten years before. Discoveries in other Cordilleran territories, notably in Montana and Idaho, made up, however, in part for the deficiency of California, so that in 1860 the total amount of gold produced in the United States was estimated at not less than $45,000,000. In the latter part of the decade 1850-1859 the territories adjacent to California on the east, north and south were overrun by thousands of miners from the Sierra Nevada goldfields, and within a few years an extraordinary number of discoveries were made, some of which proved to be of great importance. The most powerful impulse to mining operations, and the immediate cause of a somewhat lengthy period of wild excitement and speculation, was the discovery and successful opening of the Comstock lode in 1859, in the western part of what is now Nevada, but was then part of Utah. About this lode grew up Virginia City. From 1859 to 1902 the total yield of this lode was $204,653,040 in silver and $148,145,385 in gold; the average annual yield from 1862 to 1868 was above eleven millions; the maximum yield $36,301,537 in 1877; and the total product to July 1880 was variously estimated at from $304,752,171.54 to $306,181,251.25. The lode was an ore channel of great dimensions included within volcanic rocks of Tertiary age, themselves broken through pre-existing strata of Triassic age, and exhibited some of the features of a fissure vein, combined in part with those of a contact deposit and in part with those of a segregated vein. The gangue was quartz, very irregularly distributed in bodies often of great sizes, for the most part nearly or quite barren of ore. The metalliferous portion of the lode was similarly distributed in great masses, known as “bonanzas.” The next most famous lode is that of Leadville, Colorado, which from 1879 to 1889 yielded $147,834,186, chiefly in silver and lead. In later years the Cripple Creek district of Colorado became specially prominent.
The total output of gold and silver in the United States according go the tables published by the Director of the Mint has been as follows:—
| Years. | Gold. | Silver. | ||
| Quantity in Fine Ounces. |
Value. | Quantity in Fine Ounces. |
Value. | |
| $ | $ | |||
| 1792-1847 | 1,187,170 | 24,537,000 | 309,500 | 404,500 |
| 1848-1872 | 58,279,778 | 1,204,750,000 | 118,568,200 | 157,749,900 |
| 1873-1908 | 88,833,231 | 1,836,344,000 | 1,664,271,300 | 1,379,892,200 |
| 148,300,179 | $3,065,631,000 | 1,783,149,000 | $1,538,046,600 | |
Colorado ($22,871,000), Alaska ($19,858,800), California ($19,329,700), Nevada ($11,689,400), South Dakota ($7,742,200), Utah ($3,946,700), Montana ($3,160,000) and Arizona ($2,500,000) were the leading producers in 1908, in which year the totals for the two metals were $94,560,000 for gold and $28,050,600 for silver.
The grade of precious ores handled has generally and greatly decreased in recent years—according to the census data of 1880 and 1902, disregarding all base metallic contents—from an average commerical value of $29.07 to one of $8.29; nevertheless the product of gold and silver has greatly increased. This is due to improvements in mining methods and reduction processes, which have made profitable low-grade ores that were not commercially available in 1880.
Copper was produced in 1908 in twenty-four states of the Union. Their output was almost seventeenfold the quantity reported by Copper. the census of 1860. The quantity produced from 1845—the year in which the Lake Superior district became a producer, and in which the total product was only 224,000 ℔—up to 1908 was 13,106,205,634 ℔. The increases from 1845 to 1850, in each decennial period thereafter, and from 1901 to 1908, were as follows, in percentages: 50.0, 27.0, 6.1, 7.2, 14.8, 9.1 and 5.8. The total product passed 10,000,000 ℔ in 1857, 20,000,000 ℔ in 1867, 30,000,000 ℔ in 1873, 40,000,000 ℔ in 1875, 50,000,000 ℔ in 1879 and 100,000,000 ℔ in 1883. Comparing the product of the United States with that of the world, the figures for the two respectively were 23,350 and 151,936 long tons in 1879, when the United States was second to both Spain (and Portugal) and Chile as a producer; 51,570 and 199,406 long tons in 1883, when the Unites States first took leading rank; 172,300 and 334,565 long tons in 1895, when the yield of the United States first exceeded that of all other parts of the world combined; and 942,570,000 and 1,667,098,000 ℔ in 1908.
The three leading producing states or Territories of the Union are, and since the early 'eighties have been, Arizona, Montana and Michigan. With Utah and California their yield in 1908 was 93% of the total. During the decade ending with that year the average yearly output of the three first-named was 197,706,968 ℔, 267,172,951 ℔ and 12,187,488 ℔ respectively.
The production of lead was for many years limited, as already mentioned, to two districts near the Mississippi: one the so-called Lead. Upper Mines of Wisconsin, Iowa and Illinois; the other the Lower Mines of south-eastern Missouri. The national government, after reserving the mineral lands (1807) and attempting to lease them, concluded in 1847 to sell them, owing to the difficulty of preventing illegal entry and collecting royalties. The yield of the Upper Mines culminated about 1845, and long ago became insignificant. The greatest lead district is in south-western Missouri and south-eastern Kansas, known as the Joplin-Galena district after the names of the two cities that are its centre. The United States is the greatest lead producer and consumer in the world, its percentage of the total output and consumption averaging 30.4% and 32.5% respectively in the years 1904-1908. Since 1825 the total product of lead refined from domestic ores and domestic base bullion was, up to the close of 1908, 7,091,548 short tons. An annual yield of 100,000 tons was first passed in 1881; of 200,000, in 1891; of 300,000, in 1898. The total refined domestic product in'1907 was 337,340, and the total domestic lead smelted was 365,166 tons. Of the smelter domestic product 235,559 tons were of desilverized lead and 129,607 of soft lead. Considerable quantities of foreign ores and base bullion are also refined in the United States. The average percentage of metallic recovery from lead ores was about 68%, in 1880, and again in 1902, according to the national censuses of these years. According to the bureau of the census the value in 1902 of the lead yielded by copper, by non-argentiferous lead and zinc, and by gold and silver ores respectively was $19,053, $5,850,721 and $12,311,239. This reflects the revolutionary change in the history of lead mining since the first discovery of argentiferous lead ores in the Rocky Mountain states in 1864, which became available only after the building of railways. Until the completion of the Union Pacific in 1869 there was no smelting of such ores except for their silver contents. The deposits in the Joplin-Galena district were discovered in 1848, but attracted little attention for three decades. Of the soft lead smelted in 1907 no less than 94.8 % came from Missouri. Idaho, Utah and Colorado produce together almost as great a proportion of the desilverized lead, half of which has come in recent years from Idaho.
Spelter production began in the United States in 1858 in an experimental way, and regular production in 1860. The census of
