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Nevada Zinc Files Preliminary Economic Assessment

Technical Report for the Lone Mountain Zinc Project

TORONTO, Sept. 26, 2019 (GLOBE NEWSWIRE) -- Nevada Zinc Corporation (“Nevada Zinc” or the “Company”) (NZN.V) announces the filing on SEDAR of its independent Preliminary Economic Assessment (“PEA”) of the viability of potentially mining the zinc mineralization at the Company’s 100% owned Lone Mountain Project (“Project”) in central Nevada. The June 27, 2019 PEA highlights strong potential economics for a low cost, relatively simple, open pit zinc mine and flotation plant operating, producing, and selling zinc concentrate for 12 years based on the current Mineral Resource. The process plant operating rate is planned to be a nominal 800 tonnes per day (“tpd”). Using a long term average zinc price of US $1.13 per pound and an 8% discount rate, the Project generates a pre-tax Net Present Value (“NPV”) of US $56.4 M ($75.2 M CDN) and a pre-tax 40% Internal Rate of Return (“IRR”). The after tax NPV (8%) is $43.2 M ($57.6 M CDN) and the after tax IRR is 35%. All currency is stated in USD unless indicated otherwise.

Table 1 - PEA Summary

Parameters USD CAD
Pre-Tax IRR 40%  
Pre-Tax NPV 8% $56.4 M $75.2
After Tax IRR 35%  
After Tax NPV 8% $43.2 M $57.6 M
Payback Period (After Tax), (years) 2.7  
Average Annual Zinc Production (lbs. contained) 35.2 M  
Average Annual Zinc Payable (85%) (lbs. payable) 30.0 M  
Pre-production Capex $25.7 M $34.3 M
Mine Life (years) 12  
Anticipated Process Plant Throughput (Average tpd) 800  
Operating Days per Year 347  
Mineral Resource Tonnage (tonnes) 3,257,000  
Mineral Resource Grade (zinc only) 7.57%  
Anticipated Process Plant Recovery 80%  
Anticipated Grade of Concentrate Produced 45%  
Zinc Price for PEA Study (per pound) $1.13  
Foreign Exchange Rate (CAD/USD) 0.75  
     

PEA Cautionary Note
Readers are cautioned that the PEA is preliminary in nature and there is no certainty the results of the PEA will be realized. The PEA is based on inferred mineral resources that are considered too speculative geologically to have economic considerations applied to them that would enable them to be categorized as mineral reserves. A Mineral Resource is not a Mineral Reserve and does not have demonstrated economic viability. Additional drilling and studies are required to upgrade the Inferred Mineral Resource to a Mineral Reserve.

Table 2 – Overview of the PEA Results

    Base Case (USD) Base Case (CAD)
       
Commodity Assumption Zinc Price $/lb $      1.13  
       $/tonne $    2,500  
       
Economics Pre-Tax Net Cash Flow $106.7 M $142.2 M
  NPV @ 8% $  56.4 M $  75.2 M
  IRR   40%  
       
Economics After Tax Net Cash Flow $  83.8 M $111.7 M
  NPV @ 8% $  43.2 M $  57.6 M
  IRR   35%  
  Payback Period   2.7 years  
       

Capital and Operating Cost Estimates

Table 3 – Initial and Sustaining Capital Costs (CAPEX)

Area Start-up
Capital ($ M)
Sustaining
Capital ($ M)
Total ($ M)
Mining (Contractor – mobilization)   2.0       2.0  
Site Development/Infrastructure   2.0       2.0  
Mineral Processing 14.0     14.0  
Tailings Management Facility   1.0       1.0  
Closure   0.5       0.5  
Salvage Value   (0.5 )     (0.5 )
Contingencies (30%)   5.7       5.7  
Owners’ Costs   1.0       1.0  
Sustaining Capital      2.2   2.2  
Total   25.7      2.2  27.9  
           

Table 4 – Operating Costs (OPEX)

Area Cost per tonne of
Mineralized Material
($)
Cost per unit Unit
Open Pit Mining 19.50 $3.50/t Mineralized Material
$2.00/t Waste
per tonne processed
Crushing   3.00   per tonne processed
Processing 22.20   per tonne processed
G&A   2.00   per tonne processed
Total OPEX 47.70   per tonne processed
 
Note: PEA assumed that start-up working capital would be provided by concentrate purchaser on revolving credit basis.
 

The PEA was undertaken at the request of Bruce Durham, P.Geo., President and CEO of the Company and was prepared by Peimeng Ling and Associates Limited (“PL&A”) in accordance with the requirements of NI-43-101 Standards of Disclosure for Mineral Projects (“NI-43-101”). Peimeng Ling, P.Eng. (MSc. Chemical Engineering), the principal author of the Technical Report, is an independent Qualified Person (as that term is defined by Canadian regulatory guidelines) in respect of the preparation of the PEA Technical Report discussed in this press release. Her experience includes over 35 years experience in the chemical and metallurgical processing field including project evaluation and project management. Other Qualified Persons contributing to the report as filed include; Fred Brown, P.Geo., Garth Wilcox, P.Eng., David Burga, P.Geo., Jarita Barry, P. Geo.,  Richard Sutcliffe, PH.D., P.Geo, Eugene Puritch, P.Eng., FEC, CET.

Table 5 - Mineral Resource Estimate

Cut-Off Zinc % Tonnage (000’s) Pb% Zinc% Zinc M lb
5% 1,989 0.8 10.05 440
4% 2,473 0.7 8.97 489
3% 2,931 0.7 8.12 525
2% 3,257 0.7 7.57 543
1% 3,534 0.7 7.09 552

Notes: Numbers in Table 5 are from P&E Mining Consultants Inc. report dated July 22, 2018 “Initial Mineral Resource Estimate and Technical Report on the Lone Mountain Property Eureka Nevada USA”. A 2% NSR royalty is payable to the original property vendor on the majority of the Property. All material tonnes and metal values are undiluted. Mineral Resources are calculated assuming a 2% zinc cut-off. Mineral Resources which are not Mineral Reserves do not have demonstrated economic viability. The estimate of Mineral Resources may be materially affected by environmental, permitting, legal, title, socio-political, marketing or other relevant issues. Details of the Mineral Resource Estimate can be found in the technical report filed on SEDAR under the Company's profile and dated September 7, 2018.

Mining

The mineralization on the Project extends to surface and is amenable to conventional open pit mining methods utilizing front end loaders and trucks. An optimized pit shell was constructed using indicative costs for the area, including $2.50/t mining costs for waste, $3.50/t mining costs for mineralized material, a zinc price of $1.25 per pound, process recovery of 85%, smelter payout of 85%, and smelter charges and freight per tonne of concentrate of $200/t, in addition to processing costs of $20/t and G&A of $3.00/t per tonne of mineralized material. (P&E Mining Consultants Inc. 2018 see note above). Slight modifications were made to some of the parameters in light of additional investigations and results from additional metallurgical test work. The PEA established mining costs to be $2.00/t for waste and $3.50/t for mineralization. Process plant recovery was set at 80%, smelter payout was set as 85% and the achievable Zinc concentrate grade was determined to be 45% for the study while G&A was set at $2.00/t. No optimization of the planned mining of the deposit was carried out in the preparation of the PEA.

Table 6 - Processing Plant Feed Schedule

Year Total Process
Plant Feed

(tonnes 000’s)
Undiluted
Zinc Grade
(Mineral Resource
Grade)
Pounds of
Zinc
Contained in
Concentrate (M)
Total Material
Mined

(tonnes 000’s)
1 264 7.57 % 35.2 2,373
2 264 7.57 % 35.2 2,373
3 264 7.57 % 35.2 2,373
4 264 7.57 % 35.2 2,373
5 264 7.57 % 35.2 2,373
6 264 7.57 % 35.2 2,373
7 264 7.57 % 35.2 2,373
8 264 7.57 % 35.2 2,373
9 264 7.57 % 35.2 2,373
10 264 7.57 % 35.2 2,373
11 264 7.57 % 35.2 2,373
12 264 7.57 % 35.2 2,373
13 89 7.57 % 11.9 837
Total 3,257 7.57 % 434.3 29,313
 
Note: Total material mined values include all production from open pit mining (mineralization plus waste).
 

Process

The Company and its consultants have been carrying out mineralogical and metallurgical investigations on the Project’s non-sulphide zinc mineralization since October 2015. During that time the Company has completed thin section investigations, polished thin section work, Heavy Liquid Separation studies, whole rock dissolution using sulphuric acid, Tescan Integrated Mineral analyser tests, concentrate production tests using flotation techniques to concentrate the mineralization, as well as acid dissolution teswork on flotation concentrate and have also completed initial dissolution test work using the METSOL proprietary process on mineralized rock samples. The dissolution testwork on flotation concentrate material using sulphuric acid was designed to target the dissolution of the zinc minerals to produce a liquid comprised primarily of zinc sulphate. Zinc sulphate product was targeted as an end product that would ideally be an end product for use in the fertilizer or animal food businesses. The dissolution test work completed using the METSOL process was aimed at determining the viability of leaching zinc bearing rock without dissolving the associated calcite and dolomite to produce chemical grade zinc oxide.

The recoverable, and potentially payable mineralization on the Project is comprised of zinc oxide and carbonate and minerals. Through the various investigations, the smithsonite and hemimorphite/willemite were found to be moderately liberated at a grind size P80 of 600 microns, 57% and 72% respectively. Additional grinding was found to liberate more of the zinc mineralization.

Flotation test work was carried out at SGS, Lakefield Ontario. Initial test work showed 96% recoveries and produced concentrate with approximately 30% zinc content. Other tests that were completed as follow-up which produced zinc recoveries over 80% recovery and grading more than 40% zinc. Because the tests were preliminary and single batch tests only, it is reasonable to assume that a higher grade of concentrate, up to 45% could be produced with recovery of approximately 80% in more advanced testwork. Another bulk flotation test produced a 46% zinc concentrate with a 67.4% recovery. Again, the sample was a batch test only, so in a locked cycle environment it is considered reasonable that a 45% zinc concentrate could be produced at an 80% recovery rate.

As part of the plan by the Company to determine the best approach to maximize the value of the mineralization, the Company had SGS undertake leach test work using sulphuric acid to attempt leaching of the flotation concentrate. Test work by Outotec in 2016 showed the unconcentrated mineralization was readily leached however the high acid consumption rates would not allow the dissolution of raw mineralization to be a viable processing route. SGS completed 9 leach tests on various flotation concentrates. On the basis of the 9 tests, the conclusions were that in most of the tests, high zinc extraction was achieved. The method of acid addition seemed to have an effect on extraction of silicon. When acid was added slowly only limited silicon was dissolved (~5%).

A report by Metsol in March 2017 describing work completed by them reported the results of leaching of mineralized samples from the Project using the Metsol process, a non-acid leach technique. That work showed the mineralization had characteristics well suited for the leaching of mineralization to produce a zinc oxide product. Leach extraction was shown to be in the range of 80% to over 90% in the 6 samples processed. Post leaching roasting of the material produced a purity of 99.3%.

Table 7 – Sensitivitiy analysis NPV 8% Pre-Tax Base Case

      NPV

 
NPV NPV IRR
Item Variances Value 0% 5% 10% %
             
Initial Capital Cost ($M) +15%
Base Case
-15%
22
19
16
104
107
110
68
71
75
45
48
52
35
40
47
Total OPEX
($M)
+15%
Base Case
-15%
15
13
11
83
107
131
53
71
89
35
48
62
32
40
48
Zinc metal price
$/t Zn Metal
+15%
Base Case
-15%
2,875
2,500
2,125
168
107
45
116
71
26
83
48
14
60
40
19
Zinc Grade +15%
Base Case
-15%
8.7%
7.57%
6.4%
151
107
62
104
71
39
73
48
24
54
40
26
             

Infrastructure

The Project is ideally located in east central Nevada, approximately 28 kilometres to the northwest of Eureka Nevada, a mining focused area that continues to be supportive of mining development. Highway 50 which provides the main access between Reno Nevada and Eureka passes along the southern boundary of the Project and a year round county maintained road provides access to the eastern part of the Project. Existing unmaintained roads provide access to the planned area of operations.

High voltage power transmission lines are located just to the south of the Project near Highway 50. The PEA contemplates generating power using diesel power. The determination was made that a single 1.5 MW diesel generator is sufficient to provide the power needed for the operation as planned in the PEA. A back-up generator is also included in the plan. Future planned power supply studies include the possibility of using LNG as a fuel for generated power.  Primary power generation will be located in proximity to the grinding facility in order to minimize power line requirements.

Water required for operations and general site purposes would be be supplied by local well sites located as close as possible to the plant location. No plan has been developed on the location of available wells or water rights. The Company has engaged in initial reviews of the possibilities for water rights and will continue the investigation of available water near the project site.

Permits

The Project is located on public BLM lands and patent land. To-date the Company has disturbed less than 5 acres and in order to increase the footprint of disturbance the Company will require a Exploration Plan of Operations (PoO). Mining and exploration activities included in the PoO will require items such as a description of surface disturbance activities, preliminary design reports and a description of waste rock, mineralized material, spent heap and ground water characterization. A Reclamation Plan describing the construction and closure of each facility with the associated bond cost estimate as applicable is also required. Future activities creating more than five acres of disturbance will also require that the BLM perform an appropriate National Environmental Policy Act analysis (NEPA), likely an Environmental Assessment. The NEPA analysis assesses the potential for impacts to all resources from the proposed project. No survey work has been initiated at this time although plans are being made to undertake the work.

Additional information about the Company is available on the Company’s website: www.nevadazinc.com

Bruce Durham P.Geo. Company Qualified Person, President and CEO of Nevada Zinc and Peimeng Ling, P.Eng. of Peimeng Ling Independent Qualified Person of Peimeng Ling and Associates Limited, have read and approved the technical information contained in this press release. Both Mr. Durham and Ms. Ling are Qualified Persons as defined by Canadian regulatory guidelines under NI 43-101.

Some numbers in this release are rounded and therefore some discrepancies may be present in the totals shown.

For further information contact: 

Nevada Zinc Corporation 
Suite 1660 141 Adelaide St. West
Toronto, Ontario M5H 3L5
Tel: 416-504-8821

Bruce Durham, President and CEO
bdurham@nevadazinc.com 

www.nevadazinc.com

Caution Regarding Forward-Looking Statements

This news release may contain forward-looking statements including but not limited to comments regarding the timing and content of upcoming work programs, geological interpretations, receipt of property titles, potential mineral recovery processes, etc.  Forward-looking statements address future events and conditions and therefore, involve inherent risks and uncertainties.  Actual results relating to, among other things, results of exploration, project development, reclamation and capital costs of the Company's mineral properties, and the Company's financial condition and prospects, could differ materially from those currently anticipated in such statements. These and other factors should be considered carefully and readers should not place undue reliance on the Company's forward-looking statements. The Company does not undertake to update any forward-looking statement that may be made from time to time by the Company or on its behalf, except in accordance with applicable securities laws.

Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.