Report on the Diamond Drilling and Geological Investigations of the Steve's Road Lead-Gold Occurrence, North Beaverbank, Hants County, Nova Scotia

By R. J. Ryan rjryan@gov.ns.ca

Nova Scotia Department of Natural Resources
Mineral Resources Branch
Open File Report 1997-7

This report is part of the release of Closure on Nova Scotia Department of Natural Resources Closure #C000103, North Beaverbank, Hants County. The release is planned for July 31, 1997, at 10 A. M., in the Halifax office of the Nova Scotia Department of Natural Resources.

Table of Contents

• The Steve's Road (North Beaverbank) Lead-Gold Occurrence
  • Purpose of this Report
  • Location
  • General Introduction to the Meguma Group
  • History of Mining and/or Exploration
  • Geology of the Steve's Road Area
  • Host Rocks of the Steve's Road Occurrence
  • Nature of the Mineralization
  • Geochemistry
  • Heavy Mineral Studies
  • Microprobe Data
  • Alteration
  • Drilling
• Conclusions
• References
• Appendix I
  Diamond Drillhole Lithology Logs:
  • NBR-94-1
  • NBR-94-2
  • NBR-94-3
• Appendix II
  Geochemistry
  • NBR-94-1
    • Composite Core Samples
  • NBR-94-2
    • Composite Core Samples
    • Detailed Core Samples
  • NBR-94-3
    • Analyses on Submitted Sludge Samples
    • Detailed Core Sampling
• Appendix III
  Selected Representative Microprobe Analyses of Heavy Mineral Grains

The Steve's Road (North Beaverbank) Lead-Gold Occurrence

Purpose of this Report

The discovery of the gold at Steve's Road, on land that did not have an exploration licence issued on it, provided a unique opportunity to study the geology of a disseminated gold occurrence in the Meguma Group. The area adjacent to the Steve's Road occurrence has been investigated using till geochemistry, biogeochemistry, bedrock heavy mineral studies, geophysics and diamond drilling. This paper summarizes the results of these investigations into the nature of disseminated gold mineralization at this locality. Appendix I and Enclosure 1 are the written and graphic logs of the diamond drilling. Appendix II summarizes the analytical results from the drilling. Appendix III summarizes the preliminary microprobe analyses of the heavy minerals recovered from the Steve's Road area.

Location

During the course of the 1993 central Meguma field mapping an occurrence of native lead and visible gold was discovered. The occurrence is located 3.5 km north of the Beaverbank Villa (Nursing Home), at North Beaverbank. The outcrop is on a logging road (Steve's Road) which is 300 m west and parallel to the Beaverbank Road (Highway 354) (Fig. 1) (UTM N4976310 E443890). The occurrence is located at 840 m north of the intersection with the main east-west trending logging road (Fig. 1).

General Introduction to the Meguma Group

The Meguma Group is made up of a thick sequence of meta-sedimentary strata of Cambro-Ordovician age. The Group can be subdivided into two basic units in ascending order:

1. Goldenville Formation, meta-sandstones (meta-quartzarenites, quartzites and meta-greywackes with minor slate and meta-siltstone, and
2. the Halifax Formation, slates with minor meta-sandstones and meta-siltstones (Fig. 2).

The rocks of the Meguma Group have undergone polyphase deformation forming a series of northeasterly trending, upright, tight to open, locally overturned, blanket folds with anticlinal wavelengths of 2-15 km. A series of structural events has been suggested for the eastern part of the Meguma Group (O'Brien, 1983; Smith, 1983, 1986; and Smith et al., 1985) which are probably applicable throughout the terrane. These have been categorized as D₁ to D₅ by Smith et al. (1985). This multiphase deformation has led to several well developed cleavage generations. The structural fabrics include: regional and parasitic folds, axial planar cleavages, crenulation cleavage, regional shear cleavage, kink bands, boudinage structures, and faults.

Rocks of the Meguma Group are regionally metamorphosed from greenschist to lower amphibolite grade and have been subjected to contact metamorphism adjacent to the voluminous granitoid intrusions.

The greenschist facies is dominant throughout most of the central Meguma Terrane, whereas amphibolite facies occur in the eastern and western parts of the terrane. This high temperature, low pressure, zoned metamorphism is considered regional in nature. Associated metamorphic index minerals include: biotite, garnet, cordierite, staurolite, andalusite, and sillimanite (Raeside and Jamieson, 1992). These minerals show both overgrowth and deformation textures with relation to D₂ cleavage. Regional metamorphism has a minimum age of 415-405 Ma (Reynolds et al., 1987) and post-dates the onset of regional deformation (Taylor and Schiller, 1966). Graves and Zentilli (1982) suggested that to accommodate textural relationships regional metamorphism must be pre- syn- and post deformation.

Contact metamorphism occurs adjacent to the Devono-Carboniferous plutons. Regional metamorphic isograds are crosscut by these plutons. The contact metamorphic zones range from 10 to 1000 m in width. The metamorphism is characterized by sillimanite-chiastolite or garnet-cordierite mineral assemblages. These assemblages are variably deformed by D₄ and D₅ structures.

History of Mining and/or Exploration

The area had no previously documented gold occurrences near the Steve's Road occurrence although it is approximately mid distance between the Mount Uniacke and the Renfrew Gold Districts. Gold in the Meguma has traditionally been found associated with quartz veins including: classic saddle reefs, bedding concordant veins, and discordant vein systems.

Gold was first discovered in Nova Scotia as placer deposits along the shores of the province and the first substantiated discovery was by John Campbell in 1849. The first discovery of bedrock vein hosted gold in the Meguma Terrane was at Mooseland in 1858. This led to a gold rush in the Mooseland and Tangier areas. By 1861 gold had been discovered at Goldenville, Lawrencetown, Oldham, and Waverley and by 1900 the Government of Nova Scotia had recognized more than 60 formal gold districts in the Province. The production continued almost continuously until 1939 and only sporadically since that time with the exception of the period from 1983-1987 when production was consistent. Most of the gold production took place from 1861 to 1910. The total recorded production is 47 million grams (Bates, 1987), however this figure represents a minimum figure rather than an accurate estimate of production as many of the miners were paid stipend in gold as wages and this was rarely recorded as production.

There have been many models proposed for the gold in the Meguma Group, however to date there is no one model that accommodates all of the variability exhibited by the deposits of the region. Genetic models proposed for the veins of the Meguma Group include: saddle-reef (Faribault, 1899; Keppie, 1976, Boyle, 1979, 1986), exhalative (Haynes, 1986), hydraulic fracture-fluid pumping (Douglas, 1948; Graves and Zentilli, 1982, Ryan, 1996), lateral secretion (McBride, 1978), and granite related (Newhouse, 1936; Smith and Kontak, 1988a). The vein hosted deposits are similar to the deposits of Central Victoria which have been interpreted as resulting from fault related, pumping of metamorphic fluids in the waning stages of peak metamorphism (Ramsay et al., 1996).

The gold deposits can be divided into three main types:

1. high grade (approx. 15 g/t Au) narrow gold-bearing quartz veins,
2. low grade (0.5-4 g/t Au) slate/argillite hosted, and
3. low grade (0.5-5.5 g/t Au) meta-sandstone hosted (Ryan and Smith, 1997).

The deposits may also exhibit features of a combination of two or more of the above. Almost all of the historic production (47 million g Au) has come from the high grade veins within 200 m of surface. Gold-bearing quartz veins were emplaced into dilatant zones on limbs and hinges of regional and secondary folds. Veins have been interpreted to be emplaced by hydrofracturing and minor replacement within brittle-ductile deformation zones (Smith and Kontak, 1996). Recognition of disseminated gold mineralization (types 2 and 3) in the meta-sandstones (Ryan and Smith, 1993; Smith and MacKay, 1993) and argillites has renewed interest in the Meguma deposits. Disseminated gold, with minor electrum and associated intermetallic compounds and metal alloys occur in several of the historic gold mining areas associated with slates and meta-quartzarenites which have elevated carbonate, sulphide and sericite content.

Disseminated gold mineralization in carbonate-rich argillites essentially void of quartz veins has only recently received exploration attention in Nova Scotia. The best documented occurrence of this mineralization style is the Touquoy Zone in the Moose River Gold District (Fig. 3). Historical production from the district was approximately 880,000 grams of gold with essentially all of the production from narrow bedding concordant quartz veins. In 1987 Seabright Exploration Inc. discovered argillite hosted gold mineralization adjacent to the previously mined bedding concordant veins. Diamond drilling defined a core zone to the deposit having an intersection of 32.3 m at a grade of 5.4 g/t Au. Hudgins (1989) reported a geologically inferred and indicated reserve of 2.2 million tons at 2.1 g/t gold. The area is currently being re-evaluated for bulk mineable open pit potential. Preliminary results indicate that the tonnage may be increased over previous estimates.

Historically there have been only a few reported anomalies (up to 10 g/t Au) of gold in unveined, meta-sandstones of the Goldenville Formation. However, a recent discovery (1986) at North Brookfield in the Brookfield Gold District (Fig. 3), indicates that there may be economic significance to these anomalies (Smith and MacKay, 1993). The occurrence of gold in the absence of quartz veining was considered unlikely, and therefore thorough exploration for this type of occurrence was not undertaken. In the North Brookfield area, Falconbridge Ltd. first reported gold mineralization in the meta-sandstones in 1986. Falconbridge subsequently outlined a zone of mineralization across widths of 25-35 m from drill sludges with grades of 0.5 to 9.0 g/t Au. Tri-Explorations and Abacus Minerals Corporation followed up on the original work and a best grade of 3.83 g/t Au over a 2.4 m came from a surface trench sample. The zones of the mineralization are approximately 19 m wide with a average grade of 1.15 g/t Au (Weekes et al., 1993).Host rocks consist of interbedded, blue-grey meta-sandstone and minor slate, which have been regionally metamorphosed to chlorite-biotite grade. Several thin (30 cm) slate-clast conglomerates with a sandy matrix are interbedded in the sequence. Host rocks in the district appear to have undergone minor silica, carbonate, sulphide and sericite alteration.

Smith and MacKay (1993) recovered heavy minerals from the rocks in the area and reported the occurrence of unusual grains including electrum, free gold and sulphide and metal spheroids comprised of irregularly shaped metal alloys and intermetallic compounds. The spheroids were found to contain electrum cores enclosed in a matrix of Au-Pb metal compounds surrounded by sulphides rich in Pb, As, Fe, and Cu. The irregularly shaped intermetallic grains contained metal compounds consisting of Au, Ag, Pb, Cu, As and native metals (Au, Ag, Pb, W) surrounded by sulphides (cubanite, chalcopyrite, galena, sphalerite, arsenopyrite, leollingite, pyrrhotite, and pyrite). The presence of electrum in gold deposits of the Meguma Group is very rare. The electrum grains from North Brookfield contain an average of 25 wt% Ag.

Geology of the Steve's Road Area

Strata of the Uniacke map area (Fig. 2) were divided by Ryan et al. (1996) into several informal mappable units:

1. Goldenville Lewis Lake unit made up of medium- to coarse-grained meta-sandstones (CO_Gll),
2. Goldenville Steve's Road Unit mostly quartz-rich meta-sandstones with thin interbeds of meta-siltstone and slate (CO_Gsr),
3. the Halifax Formation gradational beds of the Beaverbank unit, and
4. black sulphide-rich slates of the Rawdon unit (Cunard Member) of the Halifax Formation (CO_Hr) (Fig. 2).

The strata of particular interest for this study were the Steve's Road unit and the Beaverbank unit.

Steve's Road Unit

This stratigraphic interval is best exposed at Steve's Road and along the Beaverbank Road at North Beaverbank (Fig. 3). The unit is made up of thick, medium grained, meta-sandstones interbedded with meta-siltstones and silty slates. The fine grained intervals are more abundant at the top of the unit and overall the unit contains 10-15% fine grained beds. Many of the slates in the Beaverbank area have spots of metamorphic minerals, mostly biotite clots but occasionally fine garnets and/or sericite clots after andalusite(?) and are probably more correctly classified as hornfels. The quartzose meta-sandstones (meta-quartzarenites) are buff grey to light grey in colour but weather to a very light grey. The unit has numerous Mn-rich calcareous concretions up to several metres in diameter. Another characteristic of these beds is the presence of fine-grained meta-sandstone beds that contain up to 15% spessartine garnets. The meta-siltstone and silty slate horizons can be up to 10 m thick although they are usually 1-2 m in thickness. The base of the meta-sandstone beds exhibit a variety of sole markings and are locally extensively bioturbated. A few thin beds of quartzite (greater than 95% quartz) occur and there are also thin beds of meta-greywacke (greater than 15% clay-sized matrix). Both of these lithologies (in the strictest sense of their definitions) are extremely rare in the rest of the Goldenville Formation.

The unit is a stratigraphic equivalent to the Tancook unit in the Mahone Bay area, although lithofacies differences preclude a single nomenclature. The unit varies in thickness from 700 m in the Beaverbank area to approximately 2000 m (Tancook) in the Mahone Bay area. King (1994) has indicated that the unit has a distinctive geophysical characteristics (Fig. 4) and Ryan (1995) has shown that these rocks comprise a regionally mappable lithologic unit.

Beaverbank Unit

The gradational beds at the transition between the Goldenville and the Halifax Formations of the Meguma Group have been the focus of extensive exploration for gold. Graves and Zentilli (1982, 1988) have suggested that the manganese-rich slates and siltstones of the Goldenville Halifax Transition zone (GHT) are preferentially mineralized. The term GHT as used by Graves and Zentilli (1988) includes the lower part of the Cunard Member whereas Ryan et al. (1996) restrict its usage to the Beaverbank unit. In the Mahone Bay area of Nova Scotia these transition beds are thick and mappable (O'Brien, 1988), however at some localities in the Central Meguma area there are only a few tens of metres of transition beds. In the Uniacke Syncline area these transitional beds are mapped as the Beaverbank unit and are approximately 390 m in thickness at the Beaverbank Road section (Fig. 5). The rocks of this unit consist of interbedded fine grained meta-sandstones, meta-siltstones and spotted slates. The Beaverbank unit can be divided into two informal mapping subunits: the lower beds(CO_HBl) and the manganese-rich beds (CO_HBmn). Feetham et al. (1997) have divided the Beaverbank unit into three subunits based on geochemistry and lithology, however these are not mappable subdivisions.

The lower beds of the Beaverbank unit are characterised by 240 metres of alternating quartz-rich meta-sandstone (meta-quartzarenites) and silty slate. The two lithologies are roughly in equal proportions but the meta-quartzarenite beds are thicker towards the base of the unit. The coarser units look finer grained in the field because of pervasive close spaced pressure.

The Beaverbank unit Mn-rich beds of the upper part of the unit are approximately 150 metres thick and are characterized by tightly folded horizons of the garnet-rich rocks (coticules). Most of the folding is as tight chevron folds (kinks) however there are areas where the folding is more open and appears to occur as parasitic folding within the regional cleavage planes. The folded beds are made up of 20-50% fine sand-size spessartine garnets. These beds have a very high specific gravity and can be recognized on this basis even in the absence of the folding. This unit is similar to the transition zone (GHT) calcareous quartzite unit described by Binney et al. (1986) in the vicinity of the Eastville zinc-lead deposit. The rocks of Mn-rich unit are dark to medium grey silty slate and meta-siltstones. The unit generally coarsens upward with the uppermost 20-30 metres being dominated by fine grained meta-arenites. This grain size increase is partially due to the growth of the spessartine garnets and may therefore may not reflect the original grain size of the rocks. The unit has abundant sulphides and can be picked out as an area of high readings on the aeromagnetic data for the area (King, 1994) (Fig. 5).

Host Rocks of the Steve's Road Occurrence

The host rock for the mineralization is a Goldenville Formation meta-quartzarenite of the Steve's Road unit which is approximately 300 m stratigraphically below the contact with the Halifax Formation Beaverbank unit slates and meta-siltstones. The beds are striking east-west at 065° and dip to south at 70°. The occurrence is on the north limb of the Uniacke Syncline. The bedding in the unit is obscured by the pervasive pressure solution cleavage. Within the quartzarenite beds the only visible cleavage is the regional cleavage at 060° which dips to the south at 75-80° however, within the interbedded and overlying slates there appears to be an earlier cleavage that is more closely spaced which strikes at 055° and is dipping to the north at 80°. Sedimentary structures are variably preserved in the beds but are usually well preserved on the soles of the beds. Concretions which vary from a 2 to 30 centimetres in diameter occur with the host bed and within the adjacent beds. The nature of the concretions is not clear, upon weathering the look similar to Mn concretions however geochemical analysis suggests that Mn is only a minor component, on fresh surfaces the concretions are calcareous, suggesting that these are calcite and Mn-carbonate concretions.

The host is a medium grained quartz-rich meta-sandstone. The meta-sandstones are micaceous. The rock is approximately 80-85% quartz, 8-10% biotite+muscovite+clay, 1-4% feldspar, 1-3% carbonate and 3% opaques. The sand grains are well rounded with high sphericity and are well sorted. Minor or trace amounts of organic carbon and/or graphite are present. Bedding is obscure but crossbedding plane surfaces occur every 1 to 1.5 m. The unit is unusually light in colour on weathered surfaces, ranging from brownish-white to light buff-tan in colour. The colour of fresh surfaces is light brownish-grey. Small dark brown spherical concretions of Fe+Mn carbonates occur sporadically throughout the unit. A few thin near vertical quartz veinlets cut the outcrop and have a north-south orientation. Near vertical joints occur at approximately 3 m intervals with two main orientations, 080 and 140 degrees. The surface of the joints have a yellowish brown tint to them and are often spotted with dark brown to black iron and manganese rich oxides. The spots are generally approximately 1-2 mm in diameter and subcircular in outline.

Nature of the Mineralization

The mineralization is in the form of flakes (flattened grains) and disseminations of a grey metal (native lead and metallic alloys) (Fig. 6). The metallic nature of the minerals lustre is only evident when the mineral is scratched with a knife. The weathered surface of the grey material has a powdery dark grey to blue grey oxidation which stains parts of the outcrop adjacent to the blebs of metal. Gold visible to the naked eye was observed occurring on several of the flakes of the lead metal (Fig. 6). The flakes of the metallic material is most abundant along fracture planes but other blebs of the metal can be found on the outcrop and in many cases they do not appear to have any preferred orientation (Fig. 7). Samples have been taken for heavy mineral separation both at the discovery outcrop and at stratigraphically equivalent strata along strike of the occurrence. One sample of 2 kg was taken of the apparently unmineralized portion of the unit and the sample yielded numerous flakes of the lead (~150) and 42 grains of gold. As previously mentioned the host rock weathers to an uncharacteristically light colour and in addition the muscovites in the quartzarenites are silvery in colour. The metallic appearance of the mica makes it very difficult to distinguish the metallic material and the muscovite on the fresh surfaces of the rock.

Examination of the heavy mineral separates with a binocular microscope revealed that native silver was also present and occurs both as distinct grains (Fig. 6) and also as encrustations on the lead flakes (Fig. 6). Several lead grains have both gold and silver occurring as encrustations on the surfaces of the lead flakes (Fig. 6). Many of the grains show evidence of being bent or folded over. There are small translucent crystals of white cerussite (PbCO₃) intricately intergrown with the lead on the surface of the grains. The gold grains are large 0.2 to 0.4 mm range, whereas the lead grains can be up to 1 cm long but are most commonly 1-2 mm in diameter. Probe analysis of the several of the lead grains from the discovery outcrop gave analytical results from the microprobe consistent with nearly pure lead metal composition. The metallic flakes from other sample sites away from the discovery outcrop were variable in composition with Pb-Sb-Sn being the major components. The geochemical gold assay values for the rocks are very inconsistent and range from 40 ppb to 3600 ppb on several grab and channel samples thus suggesting the gold present is fairly coarse and therefore creating a nugget effect. Six samples from the outcrop give an analytical average of 900 ppb and therefore a value of 0.9 g/ton is assumed to be a reasonable estimate of the gold content of the outcrop.

A few sulphides are present, primarily pyrite with a trace of chalcopyrite. The sulphides are most abundant (or visible) on or near the weathered surfaces of the outcrop. They are very fine grained. In addition to the sulphides there are a few small spherical balls present. The composition of these has yet to be determined, however they appear to be similar to the metallic spheres found in the rocks at North Brookfield which have been found to contain electrum, sulphides and intermetallic compounds of variable composition (Smith and McKay, 1993).

Geochemistry

A geochemical survey over the Steve's Road Occurrence included 1 till sample, 35 red spruce biogeochemical samples, 9 samples of black spruce. The biogeochemistry consists of four north-south lines (Figs. 8, 9). The till sample had only sulphides with the heavy mineral fraction, analytical results are pending. Within the biogeochemical samples five anomalous black spruce results ranging from 17-53 ppb Au were found and five red spruce anomalies of 15-48 ppb Au occur sporadically within the survey area. Most of the anomalous results occur in an area on the survey line parallel to Beaverbank Road approximately 50-70 m west of the Beaverbank Road and 500 metres south to 150 m north of the Steve's Road horizon. The department has not had time to fully assess the elemental associations of the survey and therefore use of these conclusions here must be viewed with caution, however the surveys do indicate that gold is enriched in the area.

Heavy Mineral Studies

The heavy mineral survey consisted of 29 samples from 1200 m west of the discovery outcrop to 700 m east and from 150 m north to 310 m south (Fig. 10). Most of the samples are within two lines, one along the strike of the discovery and one perpendicular to the strike on Steve's Road (Fig. 9). At each of the sites approximately 2 kg of bedrock was sampled, the samples were then crushed and the heavy minerals separated using the MTech KMS separator. The heavy minerals were recovered at the various size fractions and then examined under a binocular microscope. Twenty-two of the samples contain lead grains or non-specific metallics and seven of the samples contained gold grains, sites of gold other than the discovery outcrop were usually restricted to 1-4 grains. Minor silver and gold was also found as encrustations on the metallic flakes. The nature of the metallic flakes is variable, some of the lead? grains are covered with a black to steel blue powdery soft material. This is interpreted to be lead oxide although no probe analysis of this material has been conducted to date. Other metallic compounds which occur are magnetic, and occur as flakes and spheres. These magnetic minerals oxidize very quickly and are often surrounded by limonite. The composition is visually a gradation from pure lead to a metallic grains that are less malleable and are more iron-rich. A sample of the purer lead has been taken for lead isotopic determination.

Microprobe Data

The heavy mineral samples were selectively picked over and various grains mounted on a carbon strip and these were analyzed at the Electron Microprobe facility at Dalhousie University. Whereas the grains were not polished the analyses in general yield low totals 50-99%, however they do give an indication of the major elemental composition of the grains (See Appendix III ).

Compositionally the most pure lead grains >90% come from the discovery outcrop SR 0+0 (Fig. 11). Grains from other samples may be predominantly Pb but most have varying amounts of Sb, Sn, Fe, Mn, Cu, Zn present. The metallic grains sometimes have Sn, Sb, Fe, Pb in near equal proportions (Fig. 11). The heavy mineral separates from the discovery outcrop had gold grains, two populations of lead-rich metallic grains as well as grains of native silver (Fig. 6). The two populations of Pb-rich flakes included Pb dominated 73-93% Pb and grains with up to 40% combined Sn and Sb. Both native silver and nearly pure gold occur as encrustations on some of the Pb rich flakes and grains. The grains from 700 m east of the discovery outcrop (SR+700 E) to 300 m west of the discovery (SR+300W) as well as those from 100 m north to 200 m south all have numerous grains of the metallic alloys with Pb usually as the dominant element. Further to the west at 1200 m from the discovery outcrop there are galena and pyrite grains as well grains of Fe and Mn metallic compounds which occasionally contain up to 2% Pb metal (Fig. 11). Galena and pyrite composite grains were also found in the sample from 700 east of the showing. The iron rich grains from the western sample are very susceptible to magnetic separation. In addition to the lead-rich grains and gold grains there are also arsenopyrite, chalcopyrite and Cu-Ni-Cr sulphides and arsenides present in many of the heavy mineral separates. These have also been identified from polished thin sections of the samples which were crushed for the heavy mineral analysis. Thin sections from the transition zone section along the Beaverbank Road 300 west and stratigraphically higher than the showing also contain these Cu-Ni-Fe sulphides and arsenites.

Alteration

Although no significant gold was encountered in the drilling, lead and metallic alloys were discovered in the core associated with zones of pervasive carbonate alteration. Silicification and quartz veining occur within the cores however no direct correlation with the presence of metals can be determined. There are four distinct types of carbonate alteration exhibited by the core from Steve's Road:

1. buff coloured carbonate replacement zones which occur at various angles to the bedding and may constitute zones of up to 75 cm thick and composed of 60% carbonate with sand-size quartz grains floating in the matrix (possible concretions),
2. spotted or streaked carbonate alteration zones with buff carbonate as discrete spots or streaks (5-30 mm in diameter),
3. fractured rocks with thin calcite veinlets (up to 1 cm in thickness) this alteration can result in rocks that are so fractured and altered that they are true breccias, and
4. "calcsilicate" veins (Fig. 12).

The "calcsilicate" zones consist of very fine grained slate with early ragged biotite and idiomorphic garnets. The matrix is dominantly sericitic with subordinate quartz. This is cut by coarse grained veins of carbonate with abundant epidote, which is sometimes intermixed (altered from garnets. The contact zone between the slate and the veins are marked by a 1-2 mm rim. This rim has abundant biotite with lesser garnets that have altered cores. Garnets are clearly enclosed in a mesh of biotite grains. The rims suggest hydrothermal alteration indicating that the veins came in as hot solutions, causing coarsening of grain size in the slate and the growth of abundant biotite. Although this type of alteration is less obvious in the thinner calcite veinlets it can be assumed that they were also emplaced by relatively hot solutions.

The metallic alloys are most abundant in the fractured brecciated zones within the thin calcite veins. This seems to fit the occurrence of the gold and lead alloys found at the discovery outcrop. The lead metals and gold were at first thought to be occurring as disseminations throughout the rocks and/or preferentially on apparent joint surfaces, however based on the observations from the core, it is likely that the surfaces were calcite fracture veinlets that had weathered out at surface.

There are numerous fractures within the core, most of which are sub-parallel to the core axis. On the fracture planes there are fine yellowish crystals of unknown composition, and this mineral also occurs as fine vug filling in the non-fractured core. In addition to the yellow mineral there are also weathered blebs of iron-rich minerals that are commonly coated with limonitic material and there are small rounded spots of a black soft mineral. The composition of these minerals is currently being evaluated by electron microprobe analysis.

Drilling

Based on the gold in the outcrop and the results of the heavy mineral survey and the geochemical survey it was decided to further evaluate the style of mineralization at this locality. Three drillholes were drilled covering approximately 300 m of stratigraphic section in three inclined holes and 450 m of core (Fig. 13). The first drillhole NBR-94-1 was inclined at 45° at a bearing of 360° and it is 22 m south of the discovery outcrop (Fig. 13). The second drillhole NBR-94-2 was collared 82 m south of the discovery outcrop and inclined at 55° to the north. The third drillhole NBR-94-3 was drilled 310 m south of the discovery outcrop and was inclined 55° at a bearing of 360°. The holes were surveyed with a Trapari to determine deviation.

The drilling was designed to evaluate the nature of the mineralization at depth below the discovery outcrop (NBR-94-1 and NBR-94-2) as well as to get stratigraphic information (NBR-94-3).

Analysis of the Core Samples:

The core was split and sampled in composite intervals by random sampling every 15-20 cm in 20 foot or 5 metre intervals for drillholes NBR-94-1 and NBR-94-2. Drilling sludges were recovered from drillhole NBR-94-3 and analyzed at 10 foot intervals. Drillhole NBR-94-3 was also sampled by composite pieces of split core at 5 metre intervals. The drillholes were also sampled in more detailed 1 to 2 metres intervals where Pb mineralization was observed or where slightly elevated gold was detected in the 5 metre interval samples or the sludge. These analyses are compiled in Appendix II of this report. The gold values from the core are low with the highest value being approximately 0.115 g/ton Au over a 5 metre interval at 55 to 60 m in drillhole NBR-94-2. Most of the samples have values of less than 0.01 g/ton Au (see Appendix II ).

Correlation of the Drillholes:

Drillhole NBR-94-1 and NBR-94-2 correlate very well with the tie being the spotted slate encountered at 69 m in 94-2 correlating to the spotted slate at 4 m in 94-1. The rest of the slates occur at approximately the same intervals in the two holes. Drillhole NBR-94-3 is estimated to have reached final depth just a few metres short of intersecting the top strata intersected in NBR-94-2. The dip angles of the bedding as estimated relative to the core axis indicate that the beds shallow at depth in the section (Fig. 13). To the south the beds are dipping more steeply than at Steve's Road. The shallowing of the dip of the beds in the drillholes is interpreted to be the result of late stage kink folding along the flank of the Uniacke Syncline (Fig. 14). Calcite and carbonate alteration as well as micro-veining are most prevalent in the Steve's Road area. The alteration and veining might be related to carbonate-rich fluids migrating up late stage brittle fractures created by the kink fold (Fig. 14).

Figures: (Not presently available)

Figure 1.

1. Location and generalized geology map of the Central Meguma area.
2. Geology and drill hole location map of Steve's Road occurrence.

Figure 2. Generalized stratigraphy of the Meguma Group in central mainland Nova Scotia (after Ryan et al., 1996).

Figure 3. General geology of the Meguma Terrane and the distribution of gold occurrences in the area, after Ryan and Smith, 1997.

Figure 4. Rock susceptibility expression of the stratigraphic units in the Steve's Road area of North Beaverbank, after King, 1994. Location of sections on Figure 5 inset.

Figure 5. Calculated second derivative aeromagnetic map of the Steve's Road area, after King 1994. Units with GHT designation are the Beaverbank unit whereas the Hr refers to the Rawdon or Cunard Member.

Figure 6. Heavy mineral grains from the Steve's Road occurrence. Top left is a large Pb metal grain in epoxy, top right shows two varieties of Pb-rich metal grains as well as native silver and gold grains. The lower two photographs show Au and Ag on Pb metal grains.

Figure 7. Upper photographs are from thin sections of a surface sample 200 m south of the discovery outcrop, garnetiferous fine grain sandstones with metallics and gold occurring as blebs or along the cleavage planes and grain boundaries. The lower photograph is of the discovery outcrop, circles and arrows indicate presence of metallic lead flakes.

Figure 8. Biogeochemistry of Ag and Au in the Steve's Road area, Au results for black spruce plotted as individual samples, red spruce barks are contoured. (after Lombard, 1997 in prep.)

Figure 9. Contour maps of red spruce bark for Pb and Zn in the Steve's Road area. (after Lombard 1997 in prep.).

Figure 10. Whole rock heavy mineral survey results for the Steve's Road area.

Figure 11. Scanning Electron Microscope images of heavy mineral grains from the surface rock samples and diamond drill hole NBR-2, Steve's Road area, North Beaverbank. Samples numbered relative to the discovery outcrop (SR 0+0) so that a sample 300 m west would be SR 0+300W.

Figure 12. Alteration styles in core from the Steve's Road drilling, white bars= 2 cm.

1. Carbonate veining and calcification of the host rock, zone associated with the metallics,
2. Near vertical calcite veinlet with Pb alloys occurring on calcite (arrow),
3. Enhanced porosity in meta-sandstone resulting from the alteration,
4. "calcsilicate" (calcite and epidote) vein with garnet rim (see arrow),
5. Spotted carbonate alteration in meta-sandstone,
6. Streaky carbonate pencil shaped rods (see arrows) as alteration, bedding perpendicular to the core axis and cleavage at 50° to axis.

Figure 13. Cross-section of the drilling at the Steve's Road Occurrence and possible interpretation of the carbonate veining.

Figure 14. Cartoon depicting the probable setting of the gold occurrence at Steve's Road.

Conclusions

The discovery of gold at Steve's Road reaffirmed that there are gold occurrences in the Meguma Group rocks that are not directly related to quartz veining. The prospecting and heavy mineral analyses of the whole rock samples demonstrated that the metallic alloys which characterize this style of gold mineralization occur over a strike length of nearly 2 km and a width of 450 m.

The metallics are intricately connected to the brecciation of the host rocks by thin calcite veinlets as seen in NBR-94-3 @ 170 m (Fig. 15). The dip change in the bedding evidenced in the drilling (Figs. 13 and 14) may indicate a late stage brittle kink fold occurs along the north flank of the Uniacke Syncline. The kink folding generated fractures that mineralizing fluids migrated up. Secondary (smaller scale folds) often enrich mineralization at anticlinal quartz vein gold occurrences in the Meguma Terrane. The presence of mineralization at Steve's road may indicate that smaller scale features also play a role in the localization of disseminated gold on synclinal limbs.

Although the drilling did not intersect significant gold mineralization, the possibility still remains that there is a "disseminated" deposit nearby. The drilling and heavy mineral survey suggests that the fluid system which gave rise to the mineralization was extensive and could possibly have created a large tonnage bulk minable deposit under the right circumstances. The area should not be abandoned as a potential exploration target on the basis of three drill holes. The positive results of this investigation are:

1. gold has been confirmed at several localities within the area, and the extent to the north and east has not been fully assessed,
2. the presence of the metallic alloys over a long strike distance of greater than 1 km confirms that the mechanism controlling this style of mineralization is large scale, and
3. the presence of the metallics at a depth of 170 m in drillhole 94-3 indicates that the mineralization (albeit with little gold) continues at depth.

All of these factors suggest that exploration within the Steve's Road area should be continued.

Figure: (Not presently available)

Figure 15. Photographs of native Pb-Sb metal grains and traces of Au on calcite veinlets, core from DDH NBR-3 at approximately 170 m depth.

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Appendix I
Drill Logs

Diamond Drillhole Lithology Log
NBR-94-1

Diamond Drillhole Lithology Log
DDH-NBR-94-2

Diamond Drillhole Lithology Log
NSDNR NBR-94-3

Appendix II

Geochemistry NBR-94-1

Composite Core Samples