Laserfiche WebLink
I* Section 5 <br />Conclusions <br />The purpose of this investigation is to characterize the environmental geochemistry of <br />stockpiled ore and development rock at the Sunday Mines Group. This investigation was <br />completed to comply with the Colorado Mined Lands Reclamation Act and associated rules by <br />assessing the potential for designated chemicals and acid- or toxic-forming materials to be <br />present at the mine site. Based on the information provided previously in this report, the data <br />collected during this investigation indicate the following: <br />¦ Designated chemicals: Designated chemicals are not present at the Sunday Mines Group. By <br />definition, designated chemicals are chemicals used in extractive metallurgical processing. <br />Extractive metallurgical processing is not completed at the Sunday Mine Group. The ore <br />produced at the mines is shipped to the Denison mill near Blanding, Utah, for extractive <br />metallurgical processing. <br />¦ Acid-forming materials: ABA, field observations, and MWMP laboratory data indicate that <br />Sunday Mines Group development rock and ore are unlikely to generate acid rock drainage <br />and are not considered acid-forming material as defined in HRMMR §1.1(2). <br />¦ Toxic-forming materials: Regarding ore material, several metals were detected at <br />concentrations exceeding their respective screening levels. Although the ore material could <br />• be considered a potentially toxic-forming material given this screening evaluation, it is a <br />marketable material and is only temporarily stored at the site for brief time periods between <br />production and off-site shipment for processing. Accordingly, further considerations <br />regarding ore material are not warranted. The potential for stockpiled development rock to <br />be classified as toxic-forming was evaluated by considering two pathways for potential toxic <br />effects: direct contact risks and potential development of toxic leachate. <br />Direct contact: Preliminary screening of direct contact risks based on comparison of total <br />metals concentrations to toxicity screening levels provided by BLM and EPA indicate that <br />most metals, including uranium and vanadium, do not exceed the screening criteria and <br />therefore do not present direct contact risks. However, the preliminary screening indicated <br />that further investigations should be conducted on arsenic to determine if potential direct <br />contact risks are likely. Further evaluation of potential direct contact risks related to arsenic <br />were conducted including electron microprobe analysis of the mineralogical forms of <br />arsenic present at the site, calculation of site-specific screening levels, and testing of the <br />bic availability of arsenic in stockpiled ore and development rock. This assessment indicates <br />that available data for development rock present at the Sunday Mines Group does not <br />suggest significant toxic-forming potential. No restrictions to currently assumed land use <br />appear necessary for protection of human health for future works or visitors to the site. <br />• <br />cm 5-1 <br />T:164 MineslTask Order 3 - DMO Sampling and Analysis Plan%Task 3.12 - Soil, Ore, Rock Data Assessment ReportlSundey Rock ReporMiinal reporI Repooffinsl Sunday Mines Group Soil Ore Rock <br />Data Assessment Report_051509.doe