THE LEAD AND SILVER MINES OF NEWBURY
By Horace C. Hover
Quarrymen while blasting rock for the State highway, recently opened a vein of argentiferous ore, which the writer was requested to examine. The quarry is on land owned by Mr. Walter C. Greeley, in Newbury, Mass. about a mile from the city line of Newburyport. The vein, as far as opened, is about ten inches wide and eight feet long, and may prove to be only a pocket. Most of the ore in sight has been taken away, and it is yet to be found what may be developed by deeper excavation. Thus far the find has interest only as showing a new location of ore. Selected specimens have been assayed with varying results. Mr. Martin Boyle, the chemist of the Towle Manufacturing Company, found silver in the galena in the proportion of 42 ounces to the ton; while an assay office in Boston, to which specimens were taken by Mr. Rufus Read, reported as high as 75 ounces. But it must be remarked that these were assays of small, choice pieces of the best ore.
The above find reminds us of previous discoveries. There are traditions of colonial excavations along the banks of the Merrimac, with sufilcient results to enable Mr. Joseph Moulton to manufacture a few silver spoons. In 1868 Edward Rogers found float ore in the Highland Pasture in Byfield. He and Albert F. Adams traced these fragments to land belonging to Mrs. Richard Jaques, from whom they bought eight acres for $350. After six tons of galena had been extracted the property was bonded to Chipman and Kelley, in August, 1874, for the sum of $100,000, and these parties at once began active operations. Chipman afterward sold out to the Hon. E. P. Shaw. A second mine was opened on the adjoining lot, belonging to the Hon. Moody Boynton. The Chipman and Boynton mines were united by tunnels, and shafts were sunk to the depth of 170 feet. Consolidation took place, and a stock company was formed under the name of the Merrimac Mining Company. Three-quarters of a mile nearer Newburyport the Lawrence Company opened a third mine; and not far from it on land owned by Robert Smith, the Bartlett Company opened a fourth mine. These four mines were along a line coinciding with the strike of the country rock, which is about N., 75 E. The dip of the veins was vertical for 30 or 40 feet, then inclining S. E.; while the dip of the country rock is N., 30 W. Besides galena, pyrites and quartz, the lodes yielded siderite, limonite, hematite, tetrahedrite, malachite, azurite, etc. The ore yielded from $150 to $250 worth of metal to the ton.
The excitement became intense and speculation was rife. Prospecting went on in all parts of Newbury, Newburyport, Boxford, Salisbury, Georgetown, and other parts of Essex County. Barren hills and arid pasture lands were in the market at fabulous prices. The climax was reached on that gala day, June 2, 1875. when Newburyport was decked as for a Fourth of July celebration; a cavalcade with a brass band headed a long procession that escorted a train of wagons loaded with 160 tons of argentiferous ore, which was finally taken on board the schooner Nadab and transported to New York city.
The mining continued for about six years, with waning results as the costs increased and the profits diminished, until in 1880 operations were practically abandoned, though it is possible that they might have been continued with more modern methods of working. Public interest has again been temporarily revived by the recent discovery already mentioned; but the conviction seems to have gained ground that silver mining does not pay in Essex County.
A glance at the local geology may not be void of interest in this connection. It would seem that the original beds of impure limestone are probably referable to the Huronian Period. These were broken through by eruptive masses that now remain in the form of syenite, diorite, gneiss and various kinds of granite. The lead, silver, gold, zinc, copper, and other metals, dispersed through the limestone as crystals, and often as minute specks, were re-deposited as pockets or veins in the numerous fissures caused by eruption. Large areas of the country are still occupied by limestone, from which formerly lime was extensively made. Here and there masses of serpentine and of a fine-grained green limestone are found, the latter getting its color from the microscopic grains of serpentine diffused through it. It is in the neighborhood of these limestones, often cropping out from diorites and granites, that the metallic veins exist, and usually with a banded structure.
An excellent geological map of Essex County has been prepared by John H. Sears, curator of geology in the Peabody Academy of Science, and was published by the Essex Institute in 1893. The metallurgy of the Newbury mines was thoroughly worked up, in 1875, 1876 and 1877, by Messrs. Shockley, Townshend, Susmann and Baldwin, whose reports are on file amid the papers of the Massachusetts Institute of Technology.
Source: Scientific American - 15th June 1901