Ironbark Zinc Limited Provides a JORC 2012 Compliant Exploration Target for the Citronen Project
Ironbark Zinc Limited provided a JORC 2012 compliant Exploration Target for the Citronen Project. Project Highlights: Updated geology model and Exploration Target, completed as part of the ongoing Bankable Feasibility Study refresh, confirms Citronen contains substantial exploration upside beyond current Mineral Resource; The Exploration Target is comprised of six areas; four of which are adjacent to current Esrum, Beach and Discovery Zone orebodies; and Substantial systematic multi-year exploration and resource development program, including geophysics, planned to coincide with the beginning of project construction Ironbark has identified an Exploration Target, in addition to the known Mineral Resource, of 40 Mt to 90 Mt at 5.0% to 7.1% zinc + lead combined. The Exploration Target is based upon review of project drilling, rock chip samples and the limited geophysical data available. A 3D geological model of the project was used to assist in identifying prospective areas. The Citronen ore body is currently defined as one of the largest undeveloped zinc resources in the world. The mineralisation was first discovered in 1993 from an extensive (+2km) zone of out-cropping sulphide mineralisation now known as the Discovery Zone (Figure 2). From this region, the drilling expanded out with the aid of some minor geophysics. Three hundred diamond drill holes for approximately 66,000m have been completed at the Project to date. The result was the definition of three deposits known as the Discovery, Beach and Esrum zones. Citronen is a sediment hosted deposit. These deposits have typically been organised into two subgroups - sedimentary exhalative (SEDEX) and Mississippi Valley Type (MVT). Recent studies propose that some deposits previously classified as SEDEX lack evidence of the "exhalative" component (Taylor, 2009) and therefore, for the purposes of exploration targeting, it is more appropriate to treat these two deposits types as one. This approach draws on the relation that ores classified as SEDEX in Leach et al. (2005) are hosted in clastic-dominated sedimentary rock sequences in mainly passive margin, continental rifts and sag basins. The mineralisation is hosted in multiple deposits in multiple horizons (Emsbo et al., 2016). The result of compiling these deposits which highlights how these deposits form in `camps' or groups such as Mt Isa-McArthur Basin (Century, Mount Isa and Hilton-George Fisher deposits) in Queensland and Brooks Range, Alaska, USA which is host to the giant Red Dog deposit. The Franklinian Basin which hosts Citronen is considered highly prospective for zinc mineralisation, it was also host to the now exhausted Polaris and Nanisivik mines in Canada and there are numerous other zinc prospects throughout northern Greenland. The Citronen Deposit is open in almost every direction and Ironbark is confident the resource will be expanded with further exploration drilling. The three known orebodies at Citronen share common metallurgy and orientation with only minor differences in the metal grade and zinc - lead ratios. The orebodies are all primarily zinc deposits with minor accessory lead mineralisation. The orebodies are each centred on a historic sulphide mound that has been covered with sediment in episodic events. In some cases, the mineralising events have reactivated later and created a series of stacked lodes termed Level 1, Level 2 and Level 3. The relatively flat-lying orebodies at Citronen have proven to be continuous with the Beach Zone mineralisation extending uninterrupted over 2,500 metres. Promisingly, it remains open to the south. The confidence level to extend these orebodies laterally is very high with the potential likelihood that further lenses will be discovered beneath the currently defined orebodies. The mineral resources currently defined at Citronen are hosted above the Lower Debris Flow geological unit. Very few holes were drilled through the Lower Debris Flow as drilling was predominantly focused on near surface, lateral extension and increasing the confidence levels (i.e. resources category). However, three holes in 1995 were drilled through the Lower Debris Flow and intersected semi-massive to massive pyrite mineralisation indicating the possibility of a Level 4 sulphide horizon. The peak grade intersected was in hole CF95-56 which returned 0.55m @ 0.3% Zn & 0.21% Pb from 343.35m. Mineralisation (4.5 - 5% Zn+Pb) has been encountered almost 4 km north west of the most northern of the known Mineral Resources, at the Western Gossans, and drill intercepts of >14% zinc have been encountered on the most southern drill hole as shown on Figure 1. Each ore body is limited only by drilling and remain open in several directions. The probability of significantly expanding the resource is considered very high. The Exploration Target of 40Mt to 90 Mt at 5.0% to 7.1% zinc + lead combined is based upon review of project drilling and the limited geophysical data available. A 3D Geological model of the project was used to assist in identifying prospective areas. Each area was systematically reviewed with tonnage ranges based on conceptual target sizes and area prospectivity. Exploration Target zinc and lead grade ranges and rock densities are based upon typical grades observed from the current Citronen Resource. The Exploration Target calculation has been based on a combination of actual exploration results as discussed in this report and proposed exploration programmes. The grade of zinc and lead mineralisation in the target areas is expected to be similar to that estimated in the resource area. There are several areas, as shown on Figure 8, where the resource block model shows high grades on the edge of the resource, and the adjacent exploration target areas therefore may also contain higher average grades. The Western Gossans is the most north-westerly area of known mineralisation within the Citronen Project and remains under-explored. Several high-grade rock chip samples (including 29.97% Zn+Pb and 14.12% Zn+Pb) have been taken from this area and not followed up with drilling; and of the four holes drilled in the area - each hole intercepted mineralisation.