The Ibid mine was a lode gold mine on 19.43 acres one and one-half miles southwest of Grizzly Flat.
Three miles south of the townsite of El Dorado was a long idle lode gold mine known as the Idaho mine. Nothing more has been reported on it.
The Ida Livingston mine was a lode gold mine on 13.81 acres of the Mother Lode, one mile north of Kelsey. The deposit consisted of a rich, 25-foot gold-bearing quartz vein that yielded up to $26 per ton of ore. It was mined prior to 1914 by way of a 150-foot shaft.
The Idlewild or Taylor mine was a large, lode gold mine on the Mother Lode two miles northwest of Garden Valley. Originally worked in 1865, it was active again from the late 1880’s to about 1902. Some additional work was done at the mine during the years 1939-41. The vein of gold bearing quartz averaged 14 feet in width and produced $4 to $8 in gold per ton of ore. The mine was developed by a 1,225-foot inclined shaft with levels every 100 feet. Ore was crushed by a huge 40-stamp mill and the concentrates treated with cyanide. The estimated total output of the mine was one-million dollars.
The Ila was an isolated lode gold claim seven miles due east of Garden Valley.
The Independence mine was a lode gold mine two miles southwest of the townsite of El Dorado. The ore was found in pockets and was mined prior to 1914.
A second Independence mine was a lode gold mine four miles northwest of Slate Mountain and about five miles southeast of Georgetown. It was active in 1933, when the ore was treated in a two-stamp mill.
A third Independence mine was a lode gold mine on 2.19 acres of the Mother Lode one mile north of Placerville.
A fourth Independence mine was a lode gold mine on 18.34 acres of the Mother Lode, one mile northwest of Kelsey.
There were several locations in and around Indian Diggings where crystallized limestone deposits were found. These mines were collectively known at the Indian Diggings mines.
The Indian Creek mine was a placer mine located on 11.20 acres one and one-half miles west of Indian Diggings.
The Indian Creek Hill Hydraulic mine was a placer mine on 25 acres, just east of Gold Hill.
The Indian Diggings Creek placer gold mine was a hydraulic mine on Indian Creek, near the town of Indian Diggings. Consisting of an ancient, gold bearing river gravel channel on limestone bedrock, it was active around 1896. This mine and the Indian Creek mine listed above may be the same mine.
The Indicator mine was a lode gold mine seven miles west of Georgetown and three miles northwest of Greenwood, just south of the Middle Fork of the American River. It was operated together with two other lode gold mines, the SWH and Martha. The three were in a row, totaled 51.162 acres and were isolated from any other lode gold mines.
The Inez (Central) mine was a lode gold mine one mile east of Nashville, near today’s Highway 49 and the Amador County line. A gold-bearing quartz vein in slate, the deposit was actively mined around 1890 by means of a 250-foot shaft.
The Ingram Dredge was a dragline dredge used to work the gold bearing gravel deposit at Horseshoe Bar on the Middle Fork of the American River (Placer County line) in 1940-42.
The Ingrom (Ingram?)mine was a lode gold claim on the Mother Lode two miles south of the town of El Dorado.
The Iowa mine was a lode gold mine on the east fork of the Mother Lode, one and one-half miles northeast of Georgetown.
The Iowa Tunnel mine was a placer mine on 60 acres one-half mile west of Newtown, two miles north of Pleasant Valley.
The Ira mine was a lode gold mine on the Mother Lode, one-half mile southeast of Placerville.
The Irish Creek mine was a placer mine on 40 acres near Irish Creek, one mile south of Garden Valley.
The Irish Creek Falls mine was a placer mine on 160 acres near Irish Creek, about two miles south of Garden Valley. It surrounded several lode gold mines.
The Irish Creek Mining Company operated a non-floating gravel washing plant on Irish Creek near Georgetown, active in 1940.
The Irish mine was a chromite mine two and one-half miles east of Rescue. In 1918, 18 tons of ore was produced from small chromite pods and stringers that were developed by open cuts.
Two and one-half miles south of Grizzly Flat, at a place called Henry’s Diggings, was the Irish Slide placer gold mine. Here a drift mine was intermittently worked after 1949 in conjunction with two other drift mines, the Payne and Christian. The claim consisted of 20 acres.
The Irland (Ireland) mine was a copper mine three miles west of Placerville. Active in 1866 and 1906 when ore containing 2% copper, along with some gold and silver, was removed. The mine was developed by a 75-foot vertical shaft and an 18-foot drift.
Another copper mine, the Iron Crown (Bob) mine, was located one mile southeast of Georgetown. It was active prior to 1902 and again around 1908. The deposit consisted of a series of copper-bearing veins with slate and serpentine walls. Even the water in the mine was copper-bearing. The mine was developed by a 75-foot shaft and open cuts.
The Isaac Bradwell and P.M. Hong mine was a somewhat isolated lode gold claim on 40 acres one half mile northeast of the town of El Dorado.
The Isaac I. Holmes mine was a placer claim on 40 acres, one mile east of Placerville.
The Isabel (Isabella, Isabell) mine was a lode gold mine on 17.95 acres of the Mother Lode, about one-half mile southeast of Garden Valley. The deposit, a two to eight-foot gold-bearing quartz vein in slate, was developed by open cuts and a 30-foot shaft. The ore was first crushed on site using “arrastres” (picture a horse or mule attached to the end of a pivoted branch which drags a large rock in a circle, crushing ore as it goes in a circle). Later, ore was shipped to the Blue Lead mine’s 20-stamp mill, a short distance away. Another Isabella Mine and Mill site was located one mile west of Garden Valley. Whether the two were associated is unknown.
One-half mile northwest of Garden Valley was a lode gold mine named the Ivanhoe mine. The mine was active prior to 1890 and developed by open cuts and a 200-foot shaft.