Lead and Zinc Mines of Dubuque, Iowaby James A. Dockal, Professor of Geology, University of North Carolina at Wilmington Lead mining in the Dubuque, Iowa area was initiated by various Native American groups hundreds of years ago and the mineral galena is infrequently found in burial mounds throughout the Midwest. Native Americans, the Meskwaki and Sauk, were actively mining lead in the area when the first Europeans arrived on the scene. First European interest in the mineral deposits began with the French fur trade circa 1650. Primitive mining efforts continued thereafter with area probably supplying lead used in the American Revolution. Julian Dubuque settled in the area of the city which bears his name in 1780's and established the first truly organized mining, smelting, and marketing operation. The area was the major lead source for use in the Civil War. Production at Dubuque effectively ended after the World War I. The United States Geological Survey looked in to the area's potential resources during and shortly after World War II. The last known production from the Dubuque area (Iowa portion of the mining area) was at the time of World War II when a small mine known as the Fessler Mine was operated near the mouth of Catfish Creek. Spelunkers (cave explorers) have been active in recent times exploring and mapping the old abandoned workings frequently giving them new names. Only a very small percentage of the old workings remain open today though as recently as the 1960's many of the underground mines could be still entered and much of the surface workings could still be seen. Recent expansion of the city to the north, west and south have resulted in the loss of any evidence of the old and historic mining activity yet one can still see some of the workings in the Mines of Spain Recreation Area, Faldorf-Dockal Wildflower Preserve, Roosevelt Park, and on the Dubuque water front still stands the Shot Tower. |
Drawing from Drawing from Calvin, S. and Bain, H. F., 1900 which portrays what most of
the mines must have been like with one serious error. Note the miners in
the lower portion working in an area with much timbering to support the
mine roof. Timbering was not necessary nor used to any significant extent
in the Dubuque mines. The depiction of the shaft with its timbering and
the operation of the windless is very accurate and typical. |
The lead and zinc deposits of the Dubuque area belong to the Mississippi Valley Type sulfide deposits. In such deposits the metal sulfides, galena (PbS), marcasite (FeS2), pyrite (FeS2) and Sphalerite (ZnS), are deposited in open pore spaces, by cool (100 to 200 o C) chloride brines which do not seem to have a direct magmatic relationship. The host rock for the Dubuque deposits is the Galena Dolomite of middle Ordovician age. The Galena Dolomite is overlain by the Maquoketa Shale of upper Ordovician age and underlain by the Decorah Formation. Minerals were deposited along joints where the joints intersected favorable horizons with open pore space. In the historical terminology of the area the joints were referred to as 'crevices' and the favorable open pore bearing horizons were known as 'openings.' Some of the portions of the openings along a crevice were large enough for a man to enter and were thus referred to as a cave as in Levens' Cave. Individual worked areas along a crevice were referred to as a 'mine' or as 'diggings' or as a 'load.' Areas of concentrated mining activity were referred to as 'ranges' as in the Pike's Peak Range.
The following list consists of all the 'names' that I know of for the mines, mining companies, caves, crevices, and in the old mining vernacular diggings, leads, loads, and ranges of the Dubuque County, Iowa portion of the Upper Mississippi Valley Zinc-Lead District. Many of the historic names have been lost as have any evidence of the same features. Some mines are only know by there recent 'spelunker' names whereas others have a variety of both historic names and spelunker names all synonyms of the same feature. To further add confusion Such-an-such Mining Company could have been working Such-and-such Mine which dug ore from Such-and-such Cave which was developed along Such-and-such Crevice. Clicking of a name (when completed) will take you to web pages which give specific information on that named feature including synonyms, correlations, and related features.
This catalogue of information is very incomplete to say the least but will I hope present the majority of information that is available at present. The incompleteness is due to a lack of record keeping by those directly involved in the mining endeavors, a lack of legislative or bureaucratic interest, an almost complete lack or reporting of the mines by the newspapers locally published during the active mining era, and a sporadic and very infrequent interest in these features by the scientific community especially the federal and state geologic surveys. Actual mining records by those involved either never were made or have been lost as during my 40 years of studying these mines I have only encountered two actual mining company reports neither of which I was allowed to examine in detail. These mines were exempt from oversight by Iowa Mining Law and hence the Office of the State Bureau of Mines, when it existed, kept no records of the operations, at least I found none as I boxed up the records of that office in its final days. After countless hours with my head stuck in a microfilm reader I concluded that the newspapers published in Dubuque during the mining era only very infrequently made a note of the mines or mining activity. Most information in the newspapers relating to the mines was of a legal nature and generally provided no information of their actual condition. Occasionally advertisements in the papers provided some clues that mining activity was going on in the area. At three points in the history of the mines the scientific community showed an interest: J. D. Whitney circa 1850-1860, Iowa Geological Survey circa 1890's to 1905, and the United States Geological Survey and the U. S. Bureau of Mines circa 1945 to 1960. A very significant volume of the information reported here comes from the reports generated during these three intervals. The bulk of the information stems from the sport caving or spelunking activities of myself and friends over the period of 1960 to 1980. To give you an idea of the incompleteness of the record consider these.
Anyone viewing the information reported here who has additional information to add, it would be warmly welcomed as I would like to view these pages as an archive of information on the Dubuque Mines.
The majority of formal mine names have been lost to history. Below is a list of mine, cave, etc. names which I have encountered and which I have some information on beyond just a name on a map. The information here consists of three categories.
Italic = historic mine (mine, load, lead, diggings) name
Bold = historic name of a crevice or cave
other = modern post mining era spelunker names
Please note that due to a change in servers I am in the process of rebuilding the information folders for each of the mines listed below. Expect to find dead links until the process is completed. Also some photographs were lost, sorry. I am currently in Dubuque working on this project, July, 2008
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This page has been created and is maintained by James A. Dockal
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