History

Tonopah is an unincorporated town and county seat of Nye County, Nevada, United States. It is located at the junction of U.S. Routes 6 and 95, approximately midway between Las Vegas and Reno. It is home to the second-richest silver strike in Nevada history and was explored extensively since the early 1900’s.

The TLC project is just outside of Tonopah to the northwest. This is a new lithium claystone discovery and there is nothing in literature concerning the deposit. It is part of the Miocene age Siebert Formation consisting of sedimentary and pyroclastic rocks (Nevada Bureau of Mines Bulletin 92, Appendix A). The area of the TLC lithium deposit must be a a sub-basin of the Siebert possibly formed in a graben or half graben, as it is the only area of the Seibert Formation documented to have diatomaceous earth layers, indicating a long-lasting lake. Indications of fossil activity (travertine terraces, sinter outcrops, et c.) are ubiquitous throughout the area of the TLC claims.


Tonopah, NV circa 1913 at the height of the silver mining boom

Famous Mizpah silver mine headframe

Topography

The Basin and Range physiographic province of the United States includes Nevada and parts of Arizona, Utah, and California. It consists of rugged nearly parallel northward-trending mountain ranges and broad arid trough. with interior drainage. Elevations range from 4,000 lo 14 ,000 feet, above sea level. The valleys are filled with thick accumulations of water-laid pyroclastic rocks, silts, fanglomerates, and evaporites. Ephemeral saline lakes and playas are found in many of the valleys as a result of interior drainage and arid climate. Gently sloping alluvial fans extend from the mouths of canyons toward the low central portions of most of the valleys.

Evidence of alpine glaciation is apparent in the higher mountains, and shorelines of Pleistocene lakes con be observed locally along the foothills. The highly alkaline soil of many of the valleys supports little vegetation other salt grass and sage, but several types of conifers abound in the mountainous areas. The climate is semiarid to arid; therefore, the region is sparsely settled because habitable areas are dependent upon surface-water supplies.

The majority of the rocks of the Siebert Formation as evidenced relative to Seibert Mountain 2 km southwest of Tonopah, were deposited under alternating fluvatile and lacustrine conditions. The Tonopah area was probably a lake, surrounded by grassy, shrub-covered plains. The margins of the lake were shallow, and detris was supplied from the erosion of older volcanic rocks plus added pyroclastic material, most of which came from vents that were later filled by Brougher Rhyolite. The lake may have been somewhat alkaline, but was occupied by gastropods, ostracods and fish. Periods of partial desiccation occurred, and temperatures occasionally may have fallen below freezing. Algal mats were present along the shore in places and lake tufa was deposited locally.

Siebert Formation at Siebert Mountain, 2 km southwest of Tonopah. White tuffs and lapillistones overlain by a thin trachyandesite flow (dark band). A flow of Brougher Rhyolite forms the top of the mountain.

The late Tertiary was a period of increasing aridity in the Great Basin (Axelrod, 1940). The climate may be comparable to that described by Axelrod (in Barrows, 1971) in the Eastgate area, 150 km to the northwest. At that locality, the Eastgate flora indicates a rainfall of about 102 cm per year, with a mean annual temperature of 10°C and a mean annual range of 12° C. The precipitation was probably seasonal, with more moisture in the winter months. Following deposition of the sediments, a number of authigenic minerals were formed, especially in the lacustrine deposits. Zeolites (erionite, clinoptilolite, and analcime) are found as alteration products of tuffaceous material in the sediments. Also, authigenic potassium feldspar is present locally as overgrowth rims on detrital potassium feldspar grains.

Geology

The region was a geosyncline during much of the Paleozoic and Mesozoic eras and great thicknesses of sedimentary rocks accumulated. In Late Jurassic time, the Nevadan orogeny accompanied the uplift of the Sierra Nevada Mountains, which bounds the province on the west. Erosion has exposed the granite core of this range. During Late Cretaceous and early Tertiary, folding and thrusting of the Laramide orogeny deformed the sediments in a southward-trending zone that extends from Canada to Mexico.

The principal intrusive rocks range from Jurassic to Miocene in age. Younger plutonic rocks are found in the eastern part of the province, whereas those in the west appear to be related to the Sierra Nevada batholith. Extrusive volcanic rocks, varying in composition from rhyolite to basalt are Tertiary to Recent in age.

High-angle faulting subsequent to the Laramide orogeny determined the present topography of long graben valleys partially filled with alluvial debris from the intervening mountains. Some of the fault arc still active, as evidenced by local displacement of alluvial fans along the flanks of some mountain ranges.

Fault Geometry

The Property is underlain by Oligocene to Miocene age rhyolitic tuffs, ignimbrites and breccias similar to the upper volcanic complex of the Sierra Madre Occidental. This succession was subjected to basin and range extensional normal faulting during the Miocene that resulted in the development of a series of half-grabens. The half-grabens locally filled with fluvial-lacustrine sediments and intercalated tuffs. Alkaline volcanism around this time is thought to have contributed lithium and other alkali metals into these basin deposits.

Controls for the lithium sedimentary sequence and resulting mineralization are believed to follow the shape of a lake in which the clays became entrained. Faults underlying the lake may have served as channel ways for lithium-rich solutions to percolate into the lake basin and possibly alter and enrich the existing clays in lithium. Alternatively, the lithium may have been sourced from underlying volcanics and remobilized into the basin sequence at a later date.

Basin Model

Formation Of A ‘Claystone’ Lithium Deposit Containing Diatomite

This diagram shows the setting of diatomite deposits in a lake and some of the processes that aided their formation. Rainfall produces streams that carry silica (Si02) and other nutrients, such as phosphorus (P), into the lake from nearby highlands. Silica also can enter the lake in air-fall ash that was erupted from vol­ canoes and deposited on the lake’s surface. Sunlight provides light for photosynthesis, which enables the diatoms to grow and bloom. After the diatoms bloom and die each year, their silica skeletons settle to the bottom of the lake and form a thin sedimentary layer. Over thousands of years, these layers accumulate to form a diatomite deposit.

Mineralization

Surface grab samples taken on the TLC claims over an area of two square miles, assay from 220 ppm to 1810 ppm lithium, with 9 samples above 1,000 ppm lithium. Clay, volcanic ash and diatomaceous earth are interlayered. There is substantial evidence of fossil hot-springs throughout the area. Some samples contain thin (mm scale) bands of sandstone, thicker sandstone beds were not sampled. Exposed sandstone beds are about 1 foot thick. The lithium mineral in the TLC samples is apparently not hectorite (a silicate mineral), as using MS 61 (4 acid) gives lower lithium values than using MS 41 (aqua regia-2 acid). CLICK MAP TO ENLARGE.

Infrastructure

TLC is about 6 miles northwest of Tonopah, off Poleline Road in Big Smoky Valley. A significant concentrating solar power plant is about 6 miles further NW of the TLC claim group, while an area formally explored for uranium is to the west. TLC’s proximity to Tonopah, offers ready access to paved roads, electricity, water and skilled labor. The region is a center of epithermal mineralization that produced 138 million ounces of silver. The Hall Molybdenum Mine (now called Liberty Mine) owned by General Moly is a few miles north of TLC. This Climax style molybdenum deposit has a resource of 1,023 billion tons, is anomalous in lithium and appears to lie on the same north-striking range fault as the TLC lithium deposit.


Nearby town of Tonopah, Nevada

Nearby Crescent Dunes Solar Project

Workplan

  • Based on comparable regional efforts, American Lithium aims to lead the way with low-cost recovery of leachable lithium claystones.
  • American Lithium will continue to verify it’s resource via sampling and drilling and formally establish the resource is amenable to low-cost recovery.