This data release includes elemental analysis of soil samples collected at breccia-pipe uranium mines, at one undeveloped breccia-pipe uranium deposit, and at a reference site in northern Arizona. Samples were collected near the Arizona 1, Canyon, Kanab North, and Pinenut uranium mines, over the EZ2 breccia-pipe uranium deposit, and at the Little Robinson Tank reference site. Samples were collected around the Arizona 1 mine after active mining had ceased during July 2015; around and within the mine yard at the Canyon mine during mine-development activity and before active mining occurred in June 2013; around and within the mine yard at the Kanab North mine during reclamation and before reclamation was completed in June 2016; around the Pinenut mine during active mining in October 2014; directly over the EZ2 deposit before any development activity occurred during November 2015; and at the Little Robinson Tank reference site during November 2015.
This data release includes data for four different types of soil samples: (type 1) incremental soil samples where more than 30 equally-spaced subsamples were collected and composited over a limited areal extent termed a decision unit and depicted generally as a trapezoidal-shaped polygon mapped within a mine yard, or surrounding a mine site; (type 2) incremental soil samples where more than 30 subsamples were collected and composited over a roughly two dimensional linear or sinuous mapped pattern following roads also termed a decision unit; (type 3) discrete integrated soil samples (Bern and others, 2019 use the term “point” for these samples) where more than 30 subsamples were collected within fenced exclosures (generally about 3 meters square) containing Big Springs Number Eight dust sampling equipment; and (type 4) integrated soil samples comprised of at least 10 subsamples collected from underneath plywood cover boards used to collect herpetofauna.
Incremental samples (types 1 and 2) were collected in triplicate from the soil surface from 0-5 centimeters (cm) depth using a Multi-Incremental Sampling Tool (MIST) collecting approximately the same volume for each subsample subject to slight variation due to variable soil conditions. The volume of soil represented by each type 1 and 2 sample is termed a decision unit (DU), the areal extent of which is defined by a mapped polygonal or sinuous or linear area, and the depth of which is the 5 cm that is sampled by the MIST. Each subsample of each triplicate incremental sample was passed through a 2-millimeter sieve and composited into a clean 19-liter bucket, with each completed triplicate sample transferred to double zip-top bags for transfer to the laboratory. Integrated samples (types 3 and 4) were collected using a plastic soil scoop to collect soil from 0-5 cm depth and were composited into double zip-top plastic bags for transfer to the laboratory. Data are divided into two different data tables based upon type: types 1 and 2 are in T1_DUSamples.csv; types 3 and 4 are in T2_BSNESamples.csv. The file DataDictionary_v1.csv defines all table headings and abbreviations.
Sample preparation and analytical techniques are described in the metadata file. This data release also includes location information for the approximate center points of the incremental sample polygons and linear features (decision units) and for the discrete integrated samples. Note, locations for incremental samples for decision units (sample types 1 and 2) are the approximate center of the geographical area (polygon, linear, or sinuous feature) over which the sample was collected. As such, the elemental values represent average concentrations for the sample volume collected over the entire geographic area and depth of 0-5 centimeters of each decision unit, and do not represent concentrations that would be measured in a discrete sample collected at that central location.