This analysis is based on occurrence potential (referred to as “potential” in this analysis) for minerals identified in the Solid Mineral Occurrence and Development Potential Report, Bighorn Basin Resource Management Plan Revision Project (BLM 2009c). “Potential” refers to the potential for or the presence (occurrence) of a concentration of one or more locatable mineral resources. It does not refer to or imply potential for development and/or extraction of the mineral resource(s). It does not imply that the potential concentration is or may be economic (i.e., could be extracted profitably). The mineral potential classification system is based on the level of potential and the level of certainty of data supporting the possible existence of minerals. The system classifies level of potential as No (O), Low (L), Moderate (M), High (H), and Not Determined (ND). The system classifies level of certainty as A (lowest certainty), B, C, and D (highest certainty). See the Solid Mineral Occurrence and Development Potential Report, Bighorn Basin Resource Management Plan Revision Project (BLM 2009c) or BLM Manual 303I, Energy and Mineral Resource Assessment for more information on the mineral potential classification system.
Methods and assumptions used in this impact analysis include the following:
Restrictions on resource uses apply throughout the life of the RMP, but can be changed by amending the RMP.
The surface management regulations at 43 CFR 3809 (outside WSAs) and 3802 (within WSAs) apply to all surface-disturbing activities for locatable minerals.
Lands not formally withdrawn or segregated from mineral entry will be available for locatable mineral entry, exploration, and development as per the regulations at 43 CFR 3800 and 3810.
The BLM must approve a plan of operations that meets all applicable statutory and regulatory requirements and will not cause unnecessary or undue degradation as per 43 CFR 3809 and 3802.
Regardless of the level of operations to be conducted (casual use, notice level, or operations under a plan of operations), a locatable mineral operator must prevent adverse impacts to threatened or endangered species and their habitat that may be affected by operations.
Locatable mineral operators may not knowingly disturb, alter, injure, or destroy any scientifically important paleontological remains or any historical or archeological site, structure, building, or object on federal lands.
Notice level operations do not require approval from the BLM (i.e., there is no “federal action”) but are bound by statutory requirements, including the ESA, the National Historic Preservation Act (NHPA), and the requirement under the Federal Land Policy and Management Act (FLPMA) to prevent unnecessary or undue degradation of public lands.
The potential for mineral resources is a prediction of the likelihood of the occurrence of these resources. The occurrence of a mineral resource does not necessarily imply that the mineral can be economically exploited or is likely to be developed; mineral occurrence potential includes both exploitable and potentially exploitable occurrences. The potential for the occurrence of a mineral resource also does not imply that the quality and quantity of the resource are known.
On lands which are open to operations under the mining law, as amended, operators may conduct casual use operations, explore, locate new mining claims, submit notices under 43 CFR 3809, or seek approval of plans of operations under 43 CFR 3802 or 43 CFR 3809. This is the case even in areas which are currently believed to have low or no potential for the occurrence or development of locatable minerals.
Known (H/D) bentonite‐bearing strata within the Planning Area (Map 4) are primarily located in the eastern half of the Planning Area, but are also found in the southern and western portions of the Planning Area near Thermopolis and Cody. Refer to the Solid Mineral Occurrence and Development Potential Report, (BLM 2009c) for detailed maps of other locatable mineral potential within the Planning Area.
Commercially important bentonite deposits in the Planning Area are found only in the Thermopolis, Mowry, and Frontier Formations. Wherever these formations crop out, the potential for bentonite occurrence is high, though not always in commercial quantities, with a certainty level of D (H/D). There is a moderate (M) potential for bentonite in portions of the lowermost Cretaceous Cody Shale, with a certainty level of D (M/D). Bentonitic clay beds occur in the Morrison, Meeteetse, and Fort Union formations, and in the Aycross and Tepee Trail formations, however these beds are not generally considered of commercial quality or significance. In the balance of the Planning Area, the potential for bentonite is low (L) with a certainty level of D (L/D).
About 346,181 acres of federal mineral estate have a known high-to-moderate potential for the occurrence of bentonite, and about 3,861,368 acres have low potential. The potential for bentonite development activity, particularly in the eastern half and southern portions of the Planning Area, is high. Bentonite will continue to be mined using surface mining methods.
Gypsum‐bearing strata within the Planning Area (Map 5) occur generally in the eastern portion of the Planning Area. Gypsum beds occur in commercial amounts only in the Jurassic Gypsum Spring Formation. Wherever this formation crops out, the potential for gypsum is high with a certainty level of D (H/D), though not always in commercial quantities. In areas where the Goose Egg Formation occurs, potential for gypsum is determined to be moderate (M) with a certainty level of C (M/C). In the balance of the Planning Area, potential gypsum is rated as low (L) with a certainty level of D (L/D).
About 115,747 acres of federal mineral estate have a known high-to-moderate potential for the occurrence of gypsum, and about 4,091,802 acres have low potential. The potential for continued gypsum mining activity, particularly in several locations in the CYFO, is high. Gypsum will continue to be mined using open pit/surface mining methods.
Potential uranium‐bearing strata within the Planning Area are located in the extreme northeast part of the Planning Area (Little Mountain Uranium District). The potential for the occurrence of uranium mineralization in the Little Mountain District, a known uranium producing area, is rated as high (H) with a certainty level of D (H/D). Potential for low level (non¬commercial grade) uranium mineralization in the Eocene Aycross and Tepee Trail formations is determined to be moderate (M) with a certainty level of B (M/B). The potential for uranium throughout the remainder of the Planning Area is rated as low (L) with a certainty level of C (L/C).
Potential thorium‐bearing strata within the Planning Area are located in small deposits in various locations throughout the Planning Area. Potential for the occurrence of thorium mineralization coincident with titaniferous black sandstone deposits in the Planning Area is rated as high (H) with a certainty level of D (H/D). The potential for thorium mineralization elsewhere in the Mesaverde Formation is rated as moderate (M) with a certainty level of B (M/B). The potential for thorium throughout the remainder of the Planning Area is rated as low (L) with a certainty level of C (L/C). Currently, there is no active exploration for or mining of thorium taking place in the Planning Area. This is not expected to change over the life of the plan.
About 130,052 acres of federal mineral estate have a known high-to-moderate potential for the occurrence of uranium, with 4,077,497 acres with low potential. There are about 213,678 acres of federal minerals with a known high-to-moderate potential for the occurrence of thorium, and about 3,995,405 acres with low potential. Currently, there is no active exploration for or mining of uranium or thorium taking place in the Planning Area. Interest in uranium exploration could increase during the planning period with a rise in uranium prices. The lack of exploration for or mining of thorium is not expected to change over the life of the plan.
The southwest-central and northwest portions of the Planning Area contain very limited quantities of placer gold. The potential for low‐grade placer gold (in non‐commercial quantities only) in specific areas of the Planning Area is rated as moderate (M) with a certainty level of C (M/C). In the balance of the Planning Area, potential is low (L) with a certainty level of B (L/B).
About 51,285 acres of federal mineral estate have a known (high) potential for the occurrence of placer gold. The potential for placer gold development activity is low for the planning period.
Titaniferous black sandstone paleoplacer deposits occur in specific locations in the southern, eastern, and northern portions of the Bighorn Basin, but are not currently being developed in the Planning Area. In areas of known titaniferous black sandstone deposits, the potential for titanium and zirconium is rated as high (H) with a certainty level of D (H/D). Potential for titaniferous sandstones in the other areas such as Absaroka foothills region is rated as low (L) with a certainty level of C (L/C). The potential for titaniferous sandstones in the balance of the Planning Area is rated as low (L) with a certainty level of C (L/C).
About 213,678 acres of federal mineral estate have a known high-to-moderate potential for the occurrence of titaniferous black sands. The potential for the development of titaniferous black sands over the planning cycle is estimated to be low, though some small-scale mining of black sand is possible.
The potential for the occurrence of all metallic minerals other than placer gold and titanium-bearing black sands is determined to be low (L) with a certainty level of C (L/C) in the Planning Area. The proper geologic conditions, namely, igneous plutons and/or metamorphosed ore bodies, do not exist in the Planning Area.
The potential for the development of these metallic minerals is considered low during the planning period.
Although discoveries of other valuable deposits of locatable minerals may occur during the planning period, bentonite and gypsum will remain the dominant locatable minerals being mined in the Planning Area. See the Solid Mineral Occurrence and Development Potential Report (BLM 2009c) for more information on the occurrence and development potential for locatable minerals within the Planning Area.