TALLAHASSEE URANIUM PROJECT
The Tallahassee Uranium Project is located in central Colorado, USA, approximately 140km southwest of Denver and 30km northwest of Canon City.
The Tallahassee Uranium Project currently comprises:
Leases over two private properties (the Taylor and Boyer ranches) that provide a 100% interest in approximately 7,400 acres that encompass the Boyer, Noah and Northwest Taylor Uranium Deposits. The lease agreements provide Tallahassee the right to explore, mine and construct infrastructure on these lands; and
Eight federal lode mining claims that cover a portion of the High Park Uranium Deposit.
The total project area is approximately 7,500 acres (see Figure 1).
History of the Tallahassee Creek Uranium District
Uranium mineralisation was first discovered in the Tallahassee Creek area in 1954. Between 1954 and 1972 sixteen small open pit and underground mines operated, with total production of approximately 80,000 tonnes of ore at an average grade of 2,500ppm U3O8, for 435,000 pounds U3O8 (see Figure 2).
Western Nuclear conducted the first systematic exploration in the district between 1962 and 1966, drilling 15 holes for 3,700m. Importantly they identified thick sequences of sandstone that were not evident at the surface or in the past producing mines.
In 1974 Cyprus Mines began acquiring land and exploring the district. In 1977 Cyprus discovered the Hansen Uranium Deposit, with a drill hole that intersected a 13 metre interval averaging 1,600ppm U3O8.
Cyprus continued to undertake broad-spaced drilling around the Hansen Deposit, discovering extensions of the uranium mineralisation in a paleochannel system that hosts what are now known to be the Northwest Taylor, Noah and Boyer Deposits (see Figure 2).
Figure 1 - Location of Tallahassee’s mineral rights within the Tallahassee Creek Uranium District, Colorado, USA.
Figure 2. Uranium Deposits and historical mines in the central-western portion of the Tallahassee Creek Uranium District.
Cyprus continued to undertake broad-spaced drilling around the Hansen Deposit, discovering extensions of the uranium mineralisation in a paleochannel system that hosts what are now known to be the Northwest Taylor, Noah and Boyer Deposits (see Figure 2). But Cyprus focused predominantly on the development of the Hansen and adjacent Picnic Tree Deposits, where multiple feasibility studies were completed, culminating in the definition of reserves at the Hansen Deposit of 27 million pounds of U3O8 at a grade of 800ppm U3O8. By 1981 all permits had been obtained to develop the Hansen Deposit by way of an open pit mining operation. But mining never commenced because of a downturn in the global uranium industry.
Between 2007 and 2014 Black Range Minerals Limited consolidated ownership of mineral rights through the Tallahassee Creek Uranium District and completed multiple drilling programs. Black Range defined JORC 2012 compliant resources, within its landholdings, that totaled 90.4 million pounds of U3O8 at a grade of 600ppm U3O8 across multiple deposits.
More than 2,220 holes have been drilled in the district, for approximately 350,000 metres.
GEOLOGY AND MINERALISATION
The uranium deposits in the Tallahassee District are tabular deposits associated with redox interfaces.
The mineralisation is hosted in Tertiary sandstones (Echo Park Formation) and/or clay bearing conglomerates (Tallahassee Creek Formation). These formations were deposited in a now extinct braided-stream fluvial system (or paleochannel). Mineralisation occurred post-sediment deposition, when oxygenated, uraniferous groundwater that moved through the host rocks encountered redox interfaces. The resultant chemical change caused the precipitation of uranium oxides, with the mineralisation typically coating the surface of pre-existing minerals and sand grains. The redox interfaces were commonly a result of the buildup of carbonaceous material within the host formation during sediment deposition.
Figure 3. Long Section through the Northwest Taylor Uranium Deposit.
The paleochannels were later partially buried by the extrusion of the Thirtynine Mile Andesite, which preserved the sedimentary sequences and allowed them to be gradually enriched with uranium.
The Hansen Deposit is hosted by the Echo Park Formation, whereas the Picnic Tree Deposit is hosted by the overlying Tallahassee Creek Formation. The Noah, Northwest Taylor and Boyer Deposits are all hosted by the more favorable Echo Park sandstones, so mineralization is generally thick and laterally continuous, and commonly comprises high-grade mineralisation within broader, lower-grade envelopes. Depth to mineralisation varies according to depth of cover as well as today’s geomorphology, and ranges from around 100 metres up to 270 metres below surface (see Figure 3).
Approximately 30km to the northeast of the Noah, Boyer and Northwest Taylor Deposits, Tallahassee holds a 100% interest in eight mining claims that cover a portion of the High Park Uranium Deposit. This mineralization is hosted by an outlier of Tallahassee Creek Formation. The average depth of this mineralisation is around 25-30 metres below surface.
A JORC 2004 Mineral Resource estimate has previously been reported for Tallahassee Resources current project area (Black Range Minerals ASX announcement dated 13 August 2007). This comprised 26 million pounds of U3O8 at a grade of 540ppm U3O8 when applying a 250ppm cut-off, with significant exploration upside remaining. The JORC 2004 resources are wholly within the Taylor and Boyer properties.
In addition to the JORC 2004 Mineral Resource estimate for the Taylor and Boyer properties, the High Park deposit also has a historical Mineral Resource estimate. The historical estimate was calculated in 1979 by Dravo Denver Operations, an independent consultant for Wyoming Minerals Corporation, it is estimated that Tallahassee’s High Park deposit contains ~ *1.3 million pounds of U3O8 at a grade of approximately 1,010ppm U3O8.
Tallahassee holds a 100% interest in eight (8) federal lode mining claims (for 120 acres) that cover a portion of the High Park Uranium Deposit.