Cypress Reports 95% Recovery of Lithium from Leach Test of Surface Claystones at Clayton Valley Project, Nevada using a Weak Acid Assay Method

May 25, 2016

Vancouver, BC - Cypress Development Corp. (TSX-V: CYP) (OTCBB: CYDVF) (Frankfurt: C1Z1) ("Cypress" or the "Company") is pleased to announce, further to its news release of April 12th, the Company has received assay results showing the feasibility of extracting lithium directly from the surface claystones without the need for roasting or other costly and complex treatments at the Company's 1520 acre Clayton Valley Project located in Esmeralda County, State of Nevada, USA.

Cypress has received leach test results of lithium extraction from the surface claystones at the Clayton Valley Project using a dilute acid method. The results show that 95% of the lithium has also been recovered using a dilute acid method, a much less aggressive acid solution compared to the industry standard, caustic, four acid method.


  1. 47 samples selected for further study average 1334 ppm Li using 4-acid leach
  2. The 47 selected samples average 1276 ppm Li using dilute acid leach
  3. The weak acid method recovered 95% of the lithium found by the 4 acid method
  4. These data indicate that a readily soluble mineral form of lithium has been found
  5. Further work using a pure water leach is ongoing
  6. Selected samples cover a 2 kilometer strike length of exposed lithium mineralization

Strong acid digestion assays (industry standard four-acid method) previously reported by Cypress show a continuously mineralized volume of lithium in claystones at surface on extensive portions of Cypress' Clayton Valley property. The compiled results show 2 kilometers of north-south strike of outcropping claystones that assay approximately 1,100 ppm Li on average and include a 1.0 kilometer strike length zone that averages 1350 ppm Li.

The lithium mineralization is contained within calcareous evaporite rocks, dominantly carbonate rich lake-bed claystones with interbedded volcanic ash units. This exposed rock section is part of the basin filling Esmeralda Formation and is believed to represent uplifted portions of the stratigraphy within which the lithium brines of the basin are found and produced, including the immediately adjacent North Resource Area currently being explored by Pure Energy Minerals.

The claystones are very fine grained sedimentary rocks that were deposited directly in to the salty, shallow lake which occupied the Clayton Valley before drying up following the last ice age. The claystones are composed of clay size particles of a volcanic ash origin. The term "claystones" as used here does not imply that the rock contains clay minerals, only that they are very fine grained. The claystone unit could be better termed a very fine grained, calcareous volcaniclastic rock. These distinctions become important when discussing the implications of the new assay results reported here.

The additional assays reported below were performed on forty-seven selected samples from the 200+ surface samples so far collected during the Company's January Phase 1 and ongoing Phase 2 exploration of the property. All assaying has been completed by ALS Chemex in Reno, Nevada.

The forty-seven selected samples were collected over a 2 km strike length and cover a wide range of initial four-acid ICP (ME-ICP61) assay lithium values. These forty seven samples have now been re-assayed using a Weak Aqua Regia digestion followed by ICP/mass spectrometry analysis. The two assay methods, the industry standard initial four acid method and the subsequent Weak Aqua Regia method differ greatly in the ability of the acid mixture to extract lithium from rock samples.

A four-acid digestion assay method uses an extremely corrosive combination of HCl (hydrochloric acid), HNO3 (nitric acid), HF (hydrofluoric acid) and HClO4 (perchloric acid). Because hydrofluoric acid dissolves silicate minerals, these digestions are often referred to as 'near-total digestions'. A four acid assay will work to extract lithium contained in any known lithium bearing mineral, including pegmatite sourced spodumene hosted lithium and lithium contained within silicate clay minerals such as hectorite (a lithium bearing smectite clay mineral).

In contrast, the Weak Aqua Regia digestion uses a much more dilute mixture of one part HNO3 (nitric acid), one part HCl (hydrochloric acid) and one part water. A much less aggressive acid solution, Weak Aqua Regia will not extract lithium from silicate minerals including spodumene, lithiophyllite and lepidolite. However, Cypress is recovering an average of 95% Li from the non silicate minerals in the claystones.

The Weak Aqua Regia method was used here as a logical next step in our effort to reveal a determination of what the composition of the lithium mineralization is within the very fine grained, calcareous volcaniclastic rock host rocks being explored at the project.

Table 1 below displays the comparison between the original four-acid assays and the new Weak Aqua Regia assays for a selection of samples covering a wide range of lithium assay values (from the initial 4 acid assays previously reported). The original Four Acid assays are listed to the left, the new Weak Aqua Regia assays in the central column and the percentage Li assay comparison between the two different assay methods is listed in the right hand column.

123135 2220 2100 95%
123136 2100 2080 99%
123137 3070 2850 93%
243681 1680 1730 100%
243687 1300 1260 97%
243691 1620 1620 100%
123208 1910 1940 100%
123209 1170 1170 100%
123210 1790 1720 96%
123211 1000 920 92%
123212 860 800 93%
123213 900 830 92%
123214 1460 1380 95%
123215 1230 1130 92%
123216 970 1110 100%
123217 1270 1230 97%
123218 1060 1020 96%
123219 770 740 96%
123220 1610 1570 98%
123221 1210 1150 95%
123222 850 820 96%
123223 900 860 96%
123224 1430 1410 99%
123225 1260 1230 98%
123226 2020 1900 94%
123227 2120 2000 94%
123228 950 970 100%
123229 1320 1300 98%
123230 1240 1160 94%
123232 1190 1090 92%
123233 1330 1350 100%
123234 1510 1460 97%
123235 2600 2490 96%
123236 2250 2060 92%
123238 710 690 97%
123239 1010 970 96%
123240 1100 1080 98%
123150 1120 1050 94%
123155 1140 1010 89%
123158 910 820 90%
123161 1230 1110 90%
123170 1290 1180 91%
123176 860 790 92%
123183 840 790 94%
123192 750 620 83%
123206 860 770 90%
243674 700 640 91%

*Notes: 1. ppm mean parts per million. 2. Li=Lithium Metal.
To convert Lithium (Li) to Lithium Carbonate (Li2CO3) multiply Li by 5.323,
For example a 1000 ppm Li assay is equivalent to 5,323 ppm Li2CO3 or 0.53% Li2CO3.

An average of 95% of the lithium assayed with the four acid method was recovered using the Weak Aqua Regia assay method. This result strongly suggests that the lithium mineralization is contained within a readily dissolved, non-silicate mineral or minerals. Given the data in the table above, potential mineralogy of the lithium mineralization incudes a complex lithium oxide, a lithium bearing carbonate or complex lithium bearing salt minerals within the calcareous volcaniclastic host rock. Importantly, while the identity of the exact lithium minerals present remains to be determined, the data strongly suggests that the lithium is not contained within refractory, hard to process, silicate minerals.

The implications of the data in Table 1 clearly indicate that the mineralogy of lithium mineralization in the surface samples from the Cypress property differs materially from other known claystone hosted lithium resources including those at Kings Valley, Humboldt County, Nevada where a huge lithium resource is bound in the silicate clay mineral hectorite.

This complicated and expensive processing required to extract lithium from the mineralization at Kings Valley is fairly similar to the processing required in pegmatite lithium deposits which are currently being aggressively pursued worldwide. Cypress is optimistic that the mineralization at its Clayton Valley project represents a unique setting where lithium extraction from rock hosted mineralization can be done using a simple, low cost and environmentally friendly approach.

Cypress is now proceeding with a series of additional studies, including another assay method using a pure water, non-acid leach. The results of these assays will be reported when final results are received and complied.

Additionally, a series of X-ray Diffraction (XRD) methods are being commenced to more clearly identify the lithium bearing minerals and to continue to explore the potential options for low-cost and low environmental impact lithium extractions options. The XRD work will be conducted at the University of British Columbia (UBC) which is recognized as a world-class mineral research facility.

The goal of the work is to substantiate the indicated potential to produce a lithium rich brine directly from the mineralized host rocks that could be further processed to produce a variety of lithium compounds for industrial applications including storage batteries.

Sub surface exploration of the outcropping mineralization will commence as soon as BLM permitting is received. Reverse circulation drilling and potentially core drilling will commence sometime in July. Drill targets have been selected to test both the surface calcareous volcaniclastic rock hosted lithium mineralization as well as to intersect the Upper Ash Aquifer in a position adjacent to the current brine drilling area of Pure Energy Minerals.

Cypress Clayton Valley, Nevada Seismic Cross Section map:

Cypress is planning to advance one or two of the drill holes deeper past the Upper Ash Aquifer to test other known brine bearing horizons including the potential of a lower gravel aquifer near the base of the Esmeralda Formation.

Robert Marvin, P.Geo, Exploration Manager for Cypress Development Corp. is the Qualified Person as defined by National Instrument 43-101 and has approved of the technical information in this release.

Private Placement:

Cypress also announces a non-brokered private placement of up to 4,000,000 units at a price of $0.12 per unit ("Unit") to raise gross proceeds of up to $480,000. Each Unit will consists of one common share and one non-transferable share purchase warrant ("Warrant"), with each Warrant entitling the holder to purchase an additional common share for a period of one year at a price of $0.15 per share from the closing date of the private placement.

A finder's fee of 7% in cash and 7% in non-transferable warrants ("Finder's Warrant") may be paid in connection with part of this private placement. Each Finder's Warrant will entitle the finder to purchase a common share of Cypress at a price of $0.15 per share for a period of one year from the closing date of the private placement.

The Company intends to utilize the proceeds of this private placement for continued exploration on its lithium properties in Nevada.

The private placement is subject to TSX Venture Exchange acceptance.

About Cypress Development Corp.:

Cypress Development Corp. is a publicly traded lithium and zinc-silver exploration company developing projects in Nevada, U.S.A.

Cypress Development Corp. has approx. 24.1 million shares issued and outstanding.

To find out more about Cypress Development Corp. (TSX-V: CYP), visit our website at


"Don Huston"


For further information contact myself or:
Don Myers
Cypress Development Corp.
Telephone: 604-687-3376
Toll Free: 800-567-8181
Facsimile: 604-687-3119


This release includes certain statements that may be deemed to be "forward-looking statements". All statements in this release, other than statements of historical facts, that address events or developments that management of the Company expects, are forward-looking statements. Although management believes the expectations expressed in such forward-looking statements are based on reasonable assumptions, such statements are not guarantees of future performance, and actual results or developments may differ materially from those in the forward-looking statements. The Company undertakes no obligation to update these forward-looking statements if management's beliefs, estimates or opinions, or other factors, should change. Factors that could cause actual results to differ materially from those in forward-looking statements, include market prices, exploration and development successes, continued availability of capital and financing, and general economic, market or business conditions. Please see the public filings of the Company at for further information.