Map/GPS
StuffThis page is devoted to researching places to prospect and finding the places you've decided to try your luck.
The Geograpic Names Information System (GNIS) is an online database of place names on the USGS web site. Listed for each place name are the county, USGS 7.5' quad map and the latitude and longitude. This information is great for getting the right map an putting the location into a GPS. To find mines in GNIS, pick the state from the drop down menu and "mine" in the feature type menu. You can optionally choose a county.
Here are the problems: GNIS will only list 2000 places at a time. If your
state has more mines (California has over 3000), you'll have to list by county.
There is no info on what mineral was mined. Almost any mineral you can think
of has been mined in California. How many of the 3000 are gold mines??
The
place names in the database are only those that have appeared on USGS maps
(I think).
Many
mines
on the
maps
were
just
shown
as
a crossed
pick & shovel
etc. with no name. For instance there are 196 mines (of any type) listed in
Placer County, CA. I have seen a list with 780 gold mines in
the county listed.
Still, if you know the name of the place you want to go and it's in the database, GNIS will be a great help finding it.
You can find a list of USGS maps here. They are listed by state.
DeLorme has an excellent series of map atlases for a number of states. They left out one thing though. Each page and grid (page 80, C1 for example) covers the same area as a more detailed USGS 7.5' map. DeLorme could have listed the names of the USGS maps but they didn't. Never fear, if you need the names of the USGS maps for the gold country in the Northern California Atlas, I am listing them here.
Maps
If you are interested in metal detecting old hydraulic mines in California, get the "Ancestral Yuba River Gold Map". It shows the location of many old mines and townsites between Interstate 80 and Quincy. Many gold prospecting shops carry the map but if they don' have it, it is published by California Gold, 48 Shattuck Square, Suite 108, Berkely, CA 94704.
Online Map Sources
TerraServer
TerraServer is a great source for digital topo maps and aerial photographs. The coverage is the US, Canada and Mexico. You put in a place name and choose topo or photo. You can then move around and zoom in and out. The great thing about Terraserver is whenever you switch between the map and the image, the area and scale remain the same. I even overlaid a semi transparent topo over the image in Photoshop and they lined up perfectly. When you download either the photo or topo, you can choose to also download a world file. This file allows GPS/map software to calibrate the map or image so you can upload/download waypoints and routes to your GPS. The only negative thing I noticed is it gets tedious to move around and zoom the maps with a slow (modem) internet connection.
California USGS topo maps can be found online at California Digital Raster Graphics (all 3000+ Topo's). These are large files - most over 5mb and some well over 10mb. They get even larger when unzipped.
The best list I have found for other areas is at GPSy.com although it is somewhat dated. If you know of a better one, please let me know.
Map stuff on CD-ROM
Geologic
Atlas of the United States, Sierra Nevada Folios
These are a series of map folios that were published between 1894 - 1900
and there are 15 on this CD-ROM. Each folio has a detailed description of
the area covered and three to five 30 minute quadrangle maps. The maps I
find
most
useful for
researching places to prospect are the Topographic and the Economic Geology
maps. They show mines and towns that aren't on any recent maps. I'm
not saying that these maps show more places than the modern maps, just
some different ones. If you have a copy of Lindgren's "Tertiary Gravels
of the Sierra Nevada", each chapter in the book corresponds to one
of these folios.
I know at least a couple of the original folios cost over $100 each a few years ago so even if you had them, you wouldn't want to take them on a trip or take them apart to have them scanned. You can just print the parts you need. The price is a "whopping" $10 donation to the Sacramento Library plus $2 shipping.
Since the data on the CD is HTML (web) based, it will work with most any operating system.
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