Remaining Colorado GLO Records Now Available

A new research tool is now available to Colorado surveyors. The Colorado BLM has made available its scanned GLO records that have not been uploaded onto the GLO Records web site. My understanding is that budgetary constraints have delayed getting these records hosted on the GLO Records web site. The records are available on a 1 TB hard drive that can be purchased at the Colorado BLM Public Room, 2850 Youngfield St., Lakewood, CO, (303) 239-3600. The cost is $100, which covers the cost of the hard drive and the time to copy the data. My suggestion is to call ahead to check on availability. The great majority of the data are in the form of high-resolution PDF files to conserve disk space.

Below is a list of the data included on the hard drive.

1. Colorado rectangular survey field notes (1859 – 1998). The data are organized into PDF files by the original bound volume numbers. The field notes are grayscale images. There is an Excel spreadsheet containing over 108,000 records included as a finding aid for the field notes. The spreadsheet is a bit kludgy to use, but with a little effort you can find the volume number and page numbers for a desired set of field notes. Surveys after 1998 (rectangular survey volumes 598 – 614) are available on the GLO Records web site.

2. Colorado mineral survey connected sheets. The GLO Records web site currently hosts 1976 Colorado connected sheets. There are 35 connected sheets (mostly within Range 80 West, 6th PM) that were missed during the scanning project. A tabloid-sized scanner was used to scan these missing connected sheets, so there are four overlapping 11”x17” tiles for each sheet. The tiles are not mosaicked. The hard drive includes a spreadsheet that lists the 35 missing connected sheets along with a finding aid created by the archivists at the Denver Regional Archives.

3. Colorado mineral survey plats. The GLO Records web site currently hosts 25,004 Colorado mineral survey plat sheets (several mineral surveys have auxiliary or multiple sheets). There are 3729 plat sheets that have not been uploaded to the GLO Records web site (Surs. Nos. 17289 through 20876). In addition, there are 46 plat sheets from earlier mineral surveys that were inadvertently skipped and an additional 14 plats that were never scanned. All of these “missing” plats are included on the BLM hard drive along with two Excel spreadsheets. The plats are in color with scan resolutions of 300 to 400 dpi.

The 3729 plat sheets on the BLM hard drive are stored in 38 PDF files. These files are named based on the original bound plat book volumes (Vols. 239 – 276). An Excel spreadsheet is included with the data. It can be searched by the mineral survey number to find the PDF file and page number.
Also included is a “data dump” spreadsheet prepared by Eastern States BLM that includes the survey DM_ID number for each mineral survey plat hosted on the GLO Records web site. This is a handy resource as mineral survey plats can be searched by the DM_ID number.

4. Colorado mineral survey field notes. There are a total of 786 bound volumes containing the Colorado mineral survey field notes (approx. 35,110 sets of field notes). To date, 700 volumes have been scanned (grayscale images). No mineral survey field notes are currently hosted on the GLO Records web site. The field notes volumes that remain to be scanned are listed in an Excel spreadsheet. In general, they encompass the earliest surveys (circa. 1868 to 1876) and the last 500 mineral surveys (Surs. Nos. 20394 to 20931; circa. 1929 – 2006). Also included on the BLM hard drive is a finding aid prepared by the archivists at the Denver Regional Archives. It is a Word document.

Over the last 4 years I have created several databases, which verify that all of the approved mineral survey plats are either on the BLM hard drive or on the GLO Records web site. Part of my work included linking each approved mineral survey plat to its respective field notes. I found one instance where a placer report did not match up with a plat. The placer report was approved, while the plat and field notes were not approved.