Strongbow Releases NI 43-101 Resource Estimate for South Crofty

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Strongbow Exploration Inc. (TSX-V: SBW) reports that it has received a Mineral Resource Estimate for the South Crofty tin ("Sn") project, located in Cornwall, UK, prepared in accordance with National Instrument 43-101 ("NI 43-101") - Standards of Disclosure for Mineral Projects. The updated Mineral Resource Estimate was calculated by P&E Mining Consultants Inc. of Brampton, Ontario. The lead author of the report is Mr. Eugene Puritch, P. Eng.

Richard Williams, P.Geo., President & CEO of Strongbow stated; "We are very pleased with this new resource estimate and the independent assessment that the South Crofty project has the potential to host a significant amount of additional Mineral Resources."


  Lower Mine Mineral Resource Estimate at 0.60% Sn Cut-Off
  Tonnes (‘000s) Sn Grade Contained Sn (tonnes)
Indicated Resource 1,660 1.81% 30,000
Inferred Resource 738 1.91% 14,100
  Upper Mine Mineral Resource Estimate at 0.60% SnEq Cut-Off*
  Tonnes (‘000s) SnEq Grade Contained SnEq (tonnes)
Indicated Resource 257 0.99% 2,500
Inferred Resource 464 0.91% 4,200
* Sn equivalent (SnEq) grade is calculated using the formula: SnEq%= Sn% + (Cu% x 0.311) + (Zn% x 0.084).

(1) 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, taxation, sociopolitical, marketing, or other relevant issues. It is noted that no specific issues have been identified as yet.

(2) The quantity and grade of reported Inferred resources in this estimation are uncertain in nature and there has been insufficient exploration to define these Inferred resources as an Indicated or Measured mineral resource and it is uncertain if further exploration will result in upgrading them to an Indicated or Measured mineral resource category.

(3) The mineral resources in this report were estimated using the Canadian Institute of Mining, Metallurgy and Petroleum (CIM), CIM Standards on Mineral Resources and Reserves, Definitions and Guidelines prepared by the CIM Standing Committee on Reserve Definitions and adopted by the CIM Council.

(4) The 0.60% Sn/SnEq resource cut-off grade was derived from the approximate March 31, 2016 two year trailing average Sn price of US$8.50/lb, Cu price of US$2.75/lb, and Zn price of US$0.90/lb, 88.5%, 85% and 70% respective process recoveries, smelter payable of 95% and refining charges of US$ Operating costs used were US$55/t mining, US$27/t processing and US$9/t G&A.

  • The Lower Mine Mineral Resource contains Sn only, and the Upper Mine Resource is a Sn equivalent Mineral Resource based on the presence of tin (Sn), copper (Cu) and zinc (Zn) mineralization.
  • The exploration drill hole database for the South Crofty Project contains 157 recent diamond drill holes totalling 30,931.82 m, 3,362 historic diamond drill holes for 90,732.81 m and 14,893 historic channels over 29,439.75 m.
  • Fifty-nine (59) mineral wireframes for twenty-four (24) lodes were constructed from mineralization intercepts in channels and drill holes at a cut-off grade of 0.60% SnEq over a minimum true width of 1.2m.
  • Assay grades were capped at 6% for Sn, 4% for Cu and 20% for Zn for the Upper Mine and 20% Sn for the Lower Mine.
  • The project has multiple targets with potential to materially increase the resource size.


  • South Crofty has an active mine permit valid until 2071, subject to certain planning conditions being addressed.
  • The mine permission area includes 26 former producing mines.
  • Some of the Sn lodes have been mined over a strike length of approximately 4km, and from surface to a depth of 1km. The lodes remain open along strike and to depth.
  • Existing mine infrastructure that is potentially useable includes 4 vertical shafts with a combined depth of 2,940m.
  • An area has been set aside for construction of a new process plant.


Western United Mines Ltd. (currently in Administration) and Cornish Minerals Limited (Bermuda) (collectively the "Companies") hold the rights to the South Crofty underground mine permission area, plus additional mineral rights over a further 7,500 Ha located in various parts of Cornwall, UK. The Companies were placed into administration in 2013 to protect the assets.

An agreement has been signed between Strongbow, Galena Special Situations Fund (the only secured creditor) ("Galena"), and Tin Shield Production Ltd. (a private company that will forego its option with Galena to acquire the project) ("Tin Shield") whereby Strongbow has the right to secure a 100% interest in Western United Mines Ltd and Cornish Minerals Limited (Bermuda) by funding the exit of the assets from administration, a process anticipated to cost approximately CDN$350,000. The material terms of the agreement, which outlines milestone payments to Galena and Tin Shield, were set out in the Company's news release dated March 17, 2016.

Readers are cautioned that Strongbow's ownership of the South Crofty project is subject to a number of conditions, including successful exit of administration and receipt of final approval for the transaction from the TSX Venture Exchange.

Details of the NI 43-101 Technical Report

Indicated and Inferred Mineral Resources have been estimated for Sn in the Lower Mine and Sn, Cu and Zn in the Upper Mine. This resource estimate is based on diamond drilling, core sampling and assaying as well as underground back and face channel sampling and chip sample assaying. Sampling during past mine operations in the Lower Mine was predominantly historic channel sampling and short hole wall drilling in drives with historic exploration drilling on strike and down dip of the workings. Recent drilling from 2008 to 2013 has tested the Upper Mine Dolcoath lodes.

The exploration drillhole database for the South Crofty Project contains 157 recent diamond drillholes totalling 30,932 m, 3,362 historic diamond drillholes for 90,733 m and 14,893 historic channels for 29,439 m.

Metal prices used for the resource estimate are US$8.50/lb Sn, US$2.75/lb Cu and US$0.90/lb Zn based on approximate LME two-year trailing averages at March 31, 2016. Process recovery assumptions are 88.5% for Sn, 85% for Cu and 70% for Zn. Given the polymetallic nature of the Upper Mine lodes, mineral wireframe modelling and resource reporting is based on tin equivalent (SnEq) grade. The SnEq calculation includes metal price and recovery: %SnEq = Sn% + (0.311 x Cu%) + (0.084 x Zn%). For the Lower Mine lodes, only tin analyses are available, therefore %SnEq is essentially Sn%.

Fifty-nine (59) mineral wireframes for twenty-four (24) lodes were constructed from mineralization intercepts in channels and drill holes at a cut-off grade of 0.60% SnEq over a minimum true width of 1.2 m. The Lower Mine lodes were modelled mostly on level plans using varying horizontal widths depending on lode dip. Minimum length of Sn mineralization along strike on the levels for inclusion in resources was 15 m. Lode widths commonly are narrower than minimum mining width and were "bulked out" to at least minimum width using adjacent assays when available and practical or to minimum width at zero grade where only the lode was sampled. In the latter case, preference was given to bulking out on the lode footwall in keeping with past mining convention at South Crofty. Upper Mine lodes, estimated predominantly from recent drilling, were modelled on vertical cross sections.

Assay grades were capped at 6% for Sn, 4% for Cu and 20% for Zn for the Upper Mine and 20% Sn for the Lower Mine. Assay composites were generated for the vein intercepts from the assays captured by GEMS software in the mineral wireframes. Channel samples from predominantly the Lower Mine, were composited at a length is 1.2 m dynamically adjusted in order that all composites in the intercept have the same length. This method ensures that the grade weighting is correctly applied for bulked out lode widths but results in variable composite lengths. Compositing for drill holes was done down hole at 1.5 m consistent lengths with review of discarded residual fragments for bias.

Four block models and several partial models were created to encompass the various lode areas: Dolcoath, Roskear, No.4-No.8-No.2-Providence; and Pryces-Tincroft. The resource block models' X axes are rotated to 60° azimuth. Block sizes are 5m x 5m x 2m vertical. Inverse distance cubed (ID3) and (ID4) interpolation was carried out using multiple search distances and search ellipses oriented to lode strikes and dips.

Historic bulk density for mining granite-hosted lodes was 2.77 t/m3 (Owen et al. 1998). Water immersion bulk density testing was carried out on-site for 119 core samples from 2010 to 2011 drill holes. Samples were obtained from the Dolcoath lodes and averaged 3.09 t/m3. To convert block model volumes to tonnes, P&E used a 2.77 t/m3 bulk density for the deep, granite-hosted lodes and 3.0 t/m3 for the killas-hosted Sn-Cu-Zn bearing lodes at Dolcoath.

Mineral Resources were classified as Indicated and Inferred based on completeness of channel sampling (levels above/below, raises), the drill hole spacing, confidence in the assaying for drilling, and geologic confidence in grade continuity.

The South Crofty Mineral Resource Estimates for the various lodes are presented in the following table:

South Crofty Mineral Resources at 0.60% Sn/SnEq Cut-off
Lode/Mine Indicated Inferred
Tonnes (k) Sn/SnEq% Tonnes (k) Sn/SnEq%
Lower Mine Lodes Sn%
No. 4 452 2.04 225 2.19
No. 2 180 1.63 13 1.12
No. 8 127 1.72 34 2.33
No.2-NCK 53 2.18 - -
Providence - - 28 2.37
Roskear A 28 2.15 50 2.15
Roskear B 90 1.93 70 1.85
Roskear BHW 24 1.77 - -
Pryces/Tincroft 298 1.67 74 2.24
Dolcoath South 226 1.67 108 1.50
Dolcoath South Branch 38 1.56 5 2.07
Dolcoath North 144 1.55 47 1.57
Dolcoath North HW - - 14 0.88
Dolcoath North FW - - 70 1.36
SUBTOTAL LOWER MINE 1,660 1.81 738 1.91
Upper Mine Lodes SnEq%*
Dolcoath Middle  89 1.01 22 0.77
Dolcoath Middle Branch 36 1.00 - -
Dolcoath Upper Main - - 274 0.81
Dolcoath Upper South Branch - - 86 .86
Dolcoath NVC - - 35 1.11
Dolcoath Little NW 11 0.82 - -
Dolcoath Little NW FW - - 1 0.86
Dolcoath Little NE - - 46 1.44
Dolcoath S. Entral 121 0.98 - -
SUBTOTAL UPPER MINE 257 0.99 464 0.91
GRAND TOTAL LOWER & UPPER MINE 1,917 1.70 1,202 1.52

* Sn equivalent (SnEq) grade is calculated using the formula: SnEq% = Sn% + (Cu% x 0.311) + (Zn% x 0.084)

Mineral Resource Estimate Sensitivity to Sn/SnEq Cut-Off

Lower Mine
Sn Cut-Off
Indicated Inferred
Tonnes (k) Sn% Tonnes (k) Sn%
0.70% 1,545 1.89 699 1.98
0.65% 1,601 1.85 719 1.94
0.60% 1,660 1.81 738 1.91
0.55% 1,714 1.77 759 1.87
0.50% 1,763 1.73 778 1.84


Upper Mine
Sn/SnEq Cut-Off
Indicated Inferred
Tonnes (k) Sn% Tonnes (k) Sn%
0.70% 200 1.09 341 1.01
0.65% 227 1.04 396 0.96
0.60% 257 0.99 464 0.91
0.55% 293 0.94 536 0.87
0.50% 328 0.90 631 0.82

About South Crofty

The South Crofty tin project is located in the towns of Pool, Camborne, and Redruth in the county of Cornwall, SW England, approximately 465km drive west of London.

There has been tin mining in Cornwall since at least 2,300 BC. The South Crofty commenced large scale production in the mid-17th century. The mine managed to continue operations until it shut down in 1998 following the tin price collapse of 1984.

Several companies attempted to revive the mine between 2001 and 2013. Significant advances were made, primarily the agreement to secure a site for future mill construction, and the grant of a mining permit which is valid until 2071, subject to certain planning conditions being met. Unfortunately, the timing of the mine permit grant coincided with the current poor market conditions in the resource sector and the assets were put into administration in 2013.

The South Crofty mine has seen production from near-surface copper mineralization and deeper tin-only mineralization. The focus for Strongbow will be to evaluate the deeper tin-only (Lower Mine) mineralization that occurs primarily below a depth of 400m beneath the surface.

Qualified Person

Mr. Eugene Puritch, P. Eng., lead author of the NI 43-101 Technical Report and a "Qualified Person" as defined in NI-43-101 has reviewed and approved the contents of this news release.

The Company will publish a Technical Report, prepared in accordance with NI 43-101 guidelines, within 45 days of this news release. For additional information, contact Richard Williams at 604-638-8005 or by e-mail at


"Richard D. Williams"
Richard D. Williams, P.Geo.

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.

This news release contains "forward-looking statements" including but not limited to statements with respect to Strongbow's plans to acquire the South Crofty tin project, Strongbow's ability to reach agreement for the settlement of secured and unsecured creditor claims which are a condition to the Companies exiting administration, the timing to complete an updated NI 43-101 technical report for the project, Strongbow's ability to obtain an increase to the water discharge permit for the South Crofty tin project, the potential to increase the Mineral Resource Estimate, its ability to deliver a positive feasibility study on the project, the commencement of commercial production from the South Crofty tin project and the estimated future net present value of the South Crofty tin project, the availability of financing for future cash payments, ongoing maintenance costs and future development work at the South Crofty tin project, in addition to the estimation of a mineral resource and the success of exploration activities.

The mineral resource figures referred to in this press release are estimates and are therefore insufficient to allow meaningful application of the technical and economic parameters to enable an evaluation of the technical or economic viability and no assurances can be given that mining of the South Crofty project will be technically viable or that the indicated levels of tin will be produced. Such estimates are expressions of judgment based on knowledge, mining experience, analysis of drilling results and industry practises. Valid estimates made at any given time may significantly change when new information becomes available. While the Company believes that the resource estimates included in this press release are well established, by their very nature, resource estimates are imprecise and depend, to a certain extent, upon statistical inferences which may ultimately prove unreliable. If such estimates are inaccurate or are reduced in the future, this could have a material adverse impact on the Company.

Forward-looking statements, while based on management's best estimates and assumptions, are subject to risks and uncertainties that may cause actual results to be materially different from those expressed or implied by such forward-looking statements, including but not limited to: risks related to receipt of regulatory approvals, the successful integration of acquisitions; risks related to general economic and market conditions; risks related to the availability of financing; the timing and content of upcoming work programs; actual results of proposed exploration activities; possible variations in mineral resources or grade; failure of plant, equipment or processes to operate as anticipated; accidents, labour disputes, title disputes, claims and limitations on insurance coverage and other risks of the mining industry; changes in national and local government regulation of mining operations, tax rules and regulations.

Although Strongbow has attempted to identify important factors that could cause actual results to differ materially from those contained in forward-looking statements, there may be other factors that cause results not to be as anticipated, estimated or intended. There can be no assurance that such statements will prove to be accurate, as actual results and future events could differ materially from those anticipated in such statements. Accordingly, readers should not place undue reliance on forward-looking statements. Strongbow undertakes no obligation or responsibility to update forward-looking statements, except as required by law.



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