A near-term production opportunity

Introduction

The Keel Zinc Project is situated in County Longford, south of Longford Town in Ireland. The project area, covering 66 km2, is comprised of two Prospecting Leases P185 and P186.

The area is covered mainly by agricultural land, much of which is poorly drained pasture and minor forestry. Both tenements have been held by major mining companies since the 1960’s, including Prospect Rio Tinto Finance & Exploration Plc (1963-2001) and Lundin Mining (2006-2012). Historical diamond drilling by Rio Tinto, Boliden Group, Lundin Mining and others has delineated two main mineralised horizons (Figure 2) more than 1km in length. Zinc, lead and silver grades from annual reports are high-grade sitting within the Keel Fault system.

Since 1960, Ireland has had a string of significant zinc-lead discoveries with an estimated 14MT of zinc metal being found, ranking it first in terms of zinc discoveries per square km and second in the world for lead discovered per square km (Source: Exploration and Mining Division Ireland 2014).

Longford’s is Junior explorer looking for ground in great metal provinces of the world. The Keel Zinc Project sits within the Irish Midlands which ranks first globally in terms of zinc deposits discovered relative to land area, with the world class Tara Underground Mine (>100Mt) located 90km away in the same geological formation (Navan Beds). Ireland has a long history of mining operations, is one of the largest exporters of zinc concentrate to European smelters and ranks ninth globally in the Fraser Institute survey for exploration.

The successful due diligence program included onsite inspections, a legal ownership review and a thorough assessment of over 40,000m of historic drill data which resulted in a Mineral Resource estimate. The estimate was completed by independent consulting firm CSA Global Pty Ltd (“CSA Global”) and resulted in an Inferred Mineral Resource estimate of 6.9Mt at 5.6% Zn and 0.8% Pb.

Keel Zinc Deposit Mineral Resource Estimate, March 2017 (4% Zn cut-off)

JORC Classification Cut-off grade Density (t/m3) Tonnes(Mt) Zn(%) Pb(%)
Inferred 4% Zn 2.85 6.9 5.6 0.8
Grand Total 2.85 6.9 5.6 0.8

Longford notes one of the most exciting outcomes of the due diligence and Mineral Resource estimate was recognition of the large, low-grade mineralisation envelopes surrounding the higher-grade mineralisation (see Figure 1). The tonnes increase rapidly when moving down the grade curve. For instance, there is 16-18Mt at 3.8% from a 2% Zn cut-off.

It is expected that as drill density is increased around high-grade zones, segments of the low-grade halos can potentially increase in grade as definition is improved with a more selective model. Currently the drill hole spacing, while variable, averages around 80 m.

Longford notes that high grades of silver mineralisation were returned from drilling by Lundin Mining in campaigns from 2005-2012 and had been reported in an historical resource estimate (American Smelting and Refining Company, 1971). Longford will assay for silver in upcoming drill programs.

Keel Mineralisation Model

The Mineral Resource estimate is based on historic drilling results obtained between 1963 and 2012. The Mineral Resource estimate has been classified as Inferred, reflecting risk relating to:

  • The assignment of assumed average density values, based on data from similar deposit types;
  • A paucity of QAQC data pertaining to the input data;
  • A wide spacing between drillholes, negatively impacting estimation quality;
  • The use of an assumed collar elevation for most input drillholes;
  • The assumption of straight drillhole paths, due to the absence of downhole survey data;
  • The geology model being based on sectional interpretations drawn from published papers; and
  • the absence of core photography for the input drillholes.

Competent Persons Statement

The information in this report that relates to Mineral Resources is based on information compiled by Mr Steve Rose and Mr Bill Guy. Mr Steve Rose is a full-time employee of CSA Global Pty Ltd and is a Fellow of the Australasian Institute of Mining and Metallurgy. Mr Bill Guy is a full-time employee of Longford Resources Limited and is a Member of the Australasian Institute of Mining and Metallurgy. Mr Steve Rose and Mr Bill Guy have sufficient experience relevant to the style of mineralisation and type of deposit under consideration and to the activity which they are undertaking to qualify as Competent Persons as defined in the 2012 edition of the Australasian Code for the Reporting of Exploration Results, Mineral Resources and Ore Reserves (JORC Code). Mr Steve Rose and Mr Bill Guy consent to the disclosure of the information in this report in the form and context in which it appears.

Regional Geology – Home of Europe’s Largest Zinc Mine

Ireland has widespread carbonate succession known as favorable hosts for Zinc deposits. The main area of carbonate occurs in the world class ore field of the Central Ireland Basin mineral province. The Keel Zinc Project sits within this central Ireland Basin. The Central Ireland Basin is dominantly formed by Navan Group Beds and shallow water carbonates.

The Keel Zinc Project is underlain by the prospective Lower Carboniferous carbonates of Navan Group. Both of the primary stratigraphic targets of the Irish carbonate orefield are present in the project area, the Waulsortian Limestone and the Navan Beds. The Navan beds host the world class Navan zinc-lead mine, Europe’s largest zinc mine.

The Waulsortian Limestone (up to 1,500m) are a regional host for a number of base metal deposits, Tynagh, Silvermines, Glamoy, Lisheen and Harberton Bridge deposits. The Waulsortian Limestone sits on the eastern side of project area and has not been a focus for historical exploration.

The company considers the area to be highly prospective for Zinc mineralization and this is highlighted by the existence of the Keel Prospect, which was discovered in the 1960’s by Rio Tinto (Figure3: Geological Cross section) and the numerous historical zinc drill intercepts reported.

Historical Exploration Activity – over 260 Drill Holes and 2700 Assay Results

Since exploration commenced in 1963, a reported over 260 drill holes, predominantly diamond drilling, have been drilled at the Keel Zinc Project including more than 100 drill holes within the primary Keel Zinc mineralisation zone. More than 2700 assay results were collected from the drilling.

In addition, an estimated 5000 soil samples have been collected for Zn soil geochemistry and historical Geophysical (IP) surveys and Geophysical (EM) surveys have been carried out as well as limited Gravity. The geochemistry and geophysical data sets will be developed as the project progresses. Currently no digital geological data base exists.

Rio Tinto built production scale infrastructure including a 5m wide shaft down to 175m with three main drives but didn’t commence mining of the Keel Zinc Mineralisation. Preliminary metallurgical test sampling was carried out using bulk samples from the shaft. Samples of the various ore types and ore grades were submitted to Warren Spring Laboratories to determine mineral dressing characteristics of the Keel mineralization. The Warren Spring tests indicated that the Keel ores were readily amenable to normal sulphide flotation techniques although the grind ability and flotation characteristics can vary within quite wide limits. Excellent concentrate grades were obtained and zinc-cadmium recoveries were consistently high. (Source: Adapted from the Rio Tinto Feasibility Study (FS) 1968)

Mineralisation and Geology

The project area defined as PL 185 and PL 186 is dominated structurally by the Keel Inlier, a northeast-plunging anticline with Lower Palaeozoic (Silurian age) rocks at its core. The Lower Palaeozoic lithologies are uncomfortably overlain by the lower Carboniferous sandstones, conglomerates and carbonates of the Navan Group.

The Keel Inlier is an anticline structural “high” with beds dipping outwards to the Northwest and Southeast of the core. The core of the inlier is approximately situated on the eastern boundary between PL 185 and PL 186 (Figure 2).

Mineralization occurs as disseminations and as stockwork sulphide mineralisation in the carboniferous clastics units within faults zones and fractures. The Keel zinc mineralisation sits in two horizons more than 1 km long and spatially relate to fractures between the two branches of the Keel fault. Importantly, the high grade mineralisation occurs mainly as coarsely crystalline cavity-fills within the fault zone.