The ongoing surface and underground drilling also encountered high grades from across the Main and Eastern extensions of the deposit.
The best intersection on the western extension included surface hole MH16-03, which returned 152.07 grams per tonne gold (36.74g/t cut) over a true width of 5m. The hole also returned 12.98g/t over 6.4m and 9.64g/t over 4.2m. The company said these results extended the high-grade mineralisation 200m down plunge from the existing inferred resource.
Surface hole MH17-01, drilled in the Main extension returned 56.6g/t gold (44.03g/t cut) over 4.81m; 45.14g/t (34.73g/t cut) over a true width of 3.14m; and 12.02g/t gold over 3.68m.
High-grade mineralisation was now extended 90m above the closest previous intersections, with another one of the best surface directional intersections to date, the company said.
The high-grade material was extended up plunge and closed the gap with inferred resources in the eastern extension.
The mid-tier gold producer that also owns the Young-Davidson mine in northern Ontario and the Mulatos and El Chanate mines in Mexico, said the high-grade mineralisation was now also traced 1,000m further east of the current mine workings and remained open to the east and down plunge.
Meanwhile, underground drilling was being carried out from the 450, 620, 730 and 840 levels to upgrade inferred to indicated resources.
Cut grades and true widths included 45.64g/t gold over 2.1m; 40.79g/t over 2.2m; 33.45g/t over 2.5m; 29.07g/t over 2.7m; 18.48g/t over 3.8m; 22.94g/t over 5.3m; and 33.33g/t over 2.24m.
"Island Gold has been a tremendous success story, both in terms of the growth of the operation and its mineral reserve and resource base. With excellent ongoing exploration success including several of the best surface directional holes ever coming in the latter part of 2018, we see strong potential for this growth to continue," said CEO John McCluskey.
Alamos is trading 35% lower than a year ago and Thursday closed 1.95% or C10c down at $5.04, capitalising it at $1.97 billion. The stock last peaked at $8.00 a year ago.