Geology and Mineralization

 

At the Holt Mine, mineralized zones that have been historically mined are hosted by the McDermott shear zone, a 10 metres to 50 metres wide south-southeast dipping carbonate-sericite-chlorite ± albite altered ductile D3-D4 shear zone, which is hosted by otherwise massive and generally low strain mafic volcanic rocks. The McDermott shear zone has been traced laterally for approximately 10 km along strike, joining the Destor-Porcupine corridor to the northeast. It has been traced by drilling at least eight kilometres west of the Holt Mine headframe. The shear zone may be localized along an older D2 thrust plane that has structurally emplaced lenses of fine-grained clastic sedimentary units along it. Principal mineralized zones that have been mined to date along the structure include the South, C-104, McDermott, Worvest/Three Star, Mattawasaga, and C-97 zones, which occur over a strike length of three kilometres and have been mined to depths of over one kilometre below surface. More recently, the C-103, Zone 4 and Zone 6 gold mineralization has been identified along these geologic structures and are host to the bulk of the existing gold mineralization. All but the South Zone and Zone 4 occur in steeply south dipping sections of the shear zone. The South Zone and Zone 4 occur where the shear zone rolls to moderate to shallow southerly dips1. Prominent within the Holt Mine geology are two northeast to east-northeast trending brittle faults, the Ghostmount and the McKenna. Although once interpreted as mineralization controlling structures, they offset mineralization and are in fact the youngest structural elements in the region2.

 

(1) Rhys, D.A., Structural study of the Holloway and Holt-McDermott deposits, Ontario, with exploration implications; unpublished report for Newmont Canada Ltd., 2005a. (2) Ibid 2005a

 

Mineralization frequently occurs within the upper (hanging-wall/south) portions of the McDermott shear zone, often in areas where the structure defined by its carbonate-sericite-quartz altered high strain zone widens from a thickness of generally less than 10 metres to locally more than 50 metres wide. The widening may in part be controlled by the interaction of the shear zone with lenses of carbonaceous sedimentary rocks in its footwall. Mineralization occurs in massive to banded quartz-carbonate-pyrite-albite alteration that occurs within the McDermott shear zone and may extend a short distance into adjacent, unfoliated, massive mafic volcanics. Diffuse quartz veinlet networks and matrix are commonly developed, locally imparting breccia textures in sheared rocks. The apparent overprinting of foliation by alteration, and rotation of shear zone fabrics in breccia fragments, collectively suggest that mineralization overprints portions of the McDermott shear zone, and that it formed during or after most shear zone fabric development. An early phase of hematite-bearing carbonate-albite-quartz alteration is often preserved as lenses and domains within and adjacent to the Holt Mine mineralized zones.

 

Zones 4 and 6 at the Holt Mine have a well established higher grade gold zone (i.e. >3 g/t Au) related to a zone of more intense alteration, including sericite, chlorite, hematite and silicification, and elevated concentrations of sulphides within an overall lower grade envelope. These higher grade zones, typically three to five metres thick, are almost exclusively located along the hanging wall of the deposit, against the Ghostmount fault or any associated fault splay. The zones typically extend over 100 metres along strike and 100 metres down dip.

 

Native gold in mineralized zones at the Holt Mine occurs as fine grains spatially associated with pyrite, typically located in fractures, on grain boundaries, or encapsulated in pyrite grains. Microscopically, gold grain distribution can be clustered, however, assays do not reveal erratic or "nuggety" gold concentrations. Gold values in mineralized zones die out laterally, over several metres within the envelope of altered rock. There is generally a fairly sharp boundary on the hanging-wall side, but a more gradational lessening of values on the footwall side. This is particularly evident in Zone 4 and less evident in Zone 6 where the contacts of the mineralization are generally sharp with the surrounding mafic volcanic rocks.

 

Mineralized zones at the Holt Mine display two pronounced shoot plunges: (a) moderate to steep east plunges that outline the major zones, and (b) alignment of zones and chains of small mineralized shoots along shallow west plunging axes. The latter plunge is parallel to the plunge line of dip changes in the McDermott shear zone.

 

The reader is referred to the 2013 Holt-Holloway Technical Report for an extensive discussion of the geology of the Holt-Holloway property package.