Summary:
The Coalspur Formation at the Vista Coal Project is exposed in subcrop along the erosional eastern margin of the Prairie Creek Anticline. This margin area is bounded to the west by the Pedley Fault, a major reverse fault, which separates the folded and deformed strata of the Foothills Belt from the undeformed Alberta Syncline strata.
The structure is a simple monocline, trending 300° northwest/southeast. The beds dip gently northeast from 6° in the western part of the property up to 15° at the McLeod River on the eastern boundary.
No significant faulting has been identified on the property. Glacial ice deformation has been observed locally along the subcrop margins of the coal zones.
The property is overlain entirely by a mantle of glacial till and alluvium which varies from 5 m to 30 m in thickness. Consequently, all stratigraphic correlation and structural interpretation is based entirely on the geological modelling of drill hole data.
The coal deposits associated with the Coalspur Coal Projects (Vista Coal Project, Vista Extension and Vista South) are considered to be surface mineable, as defined in the Geological Survey of Canada Paper 88-21 (“GSC 88-21”).
In the Coalspur lease areas, the coal zones occur at depths from sub-outcrop (below the base of the overlying till material) extending down dip to over 250 m deep. The targeted Coal Resources, in terms of deposit type, are therefore defined as surface mineable.
In terms of structure, the target area can be described as being an area with low tectonic disturbance, the only main feature being the eastern monocline, resulting in strata dips of up to 10°. No major faults have been identified within the defined resource blocks notwithstanding major boundary faults. The geology type, as defined by geological complexity, is classed as moderate.
Of the six recognised coal zones encountered within the Coalspur Formation, only the Val d’Or, McLeod, McPherson and Silkstone zones maintain a persistent mineable thickness throughout the Vista lease areas and constitute the majority of the potentially mineable resource. The Arbour Zone is locally present only in the Hinton West Block, while the Mynheer Zone is usually too deep and too thin to be considered surface mineable.
The Val d’Or Zone consists of seven correlated sub-seam plies numbered from the base up from V1 through V7. Some of these plies are further divided into lower and upper units by thin partings. The individual plies maintain relatively constant thickness over the strike length of the property, while most of the variation takes place in the interbedded clastic parting material. The average zone thickness is approximately 32 m, of which some 15 m is coal. The zone thickness increases from 20 m along the eastern boundary along the McLeod River to over 60 m in the Hinton West Block. This is almost entirely due to increases in the interbedded sandstone sequence in the upper part of the zone, as the total coal thickness remains relatively constant.
The McLeod Zone consists of three correlated plies, numbered from the base up L1 to L3. These plies are typically high ash coal. The zone has an average thickness of approximately 5 m, of which some 3.7 m is coal.
The McPherson Zone consists of four plies, identified, from the base up, as P1 through P4. The McPherson plies are the most consistent in terms of thickness and continuity. The average zone thickness is nearly 7 m, of which 6 m is coal.
The Silkstone Zone is located 70 m below the McPherson Zone and consists of two distinct coal seams: the Upper Silkstone and the Lower Silkstone seams. The Upper Silkstone Seam ranges in thickness from 0.3 m to 1.0 m, while the Lower Silkstone Seam, 10 m below, consists of two coal plies separated by a thin parting. This seam ranges in thickness from 3.0 m to 3.5 m.