Silver Bull Resources (TSE:SVB) (AMEX:SVBL) provided Tuesday an update on a planned 3,000 metre underground drill program to target a high grade zone of silver at its Sierra Mojada project in Coahuila, Mexico.
The company said the campaign will target a high grade silver area
with grades up to 472 grams per tonne (g/t) of silver over 17 metres
within the Shallow Silver Zone at the project.
The high grade zone was defined by historical long hole drilling and channel samples, the company said.
Of the 150 long holes that defined the zone, Silver Bull said 75 have
average weighted intercepts of more than 80 g/t silver, and include 472
g/t silver over 17 metres, 447 g/t silver over 9 metres, 348 g/t silver
over 21 metres, 322 g/t silver over 16 metres, and 363 g/t silver over
Over 70 per cent of the long holes that defined the area ended in
mineralization. Long holes are drill holes averaging between 10 to 20
metres in length that "grind" through the rock to produce a "rock chip"
sample and underground channel samples.
The silver and zinc miner also noted that the 500 metre east-west
trending strike of the high grade zone remains open toward the east.
Silver Bull plans to start a 3,000 metre underground drill program
targeting this 500 metre-long high grade zone of silver in the middle of
There are 2,700 long holes within the historical data set that
defined the zone, representing more than 37,873 metres of drilling.
The company said, however, that the impact of the long hole data on
its latest NI 43-101 resource update on the Shallow Silver Zone in late
May was "severely restricted" due to the potential for contamination and
sample loss through the washing out of "fines" from the long hole rock
chip samples by water used in the drilling process.
After discussion with consultant and the author of the latest report,
SRK, "it has been agreed that by twinning a number of these long holes
with the more reliable "core" drilling method and then comparing and
confirming the assay results with nearby long holes, we hope to increase
the confidence of the entire long hole data set," the company said in a
If there is a high correlation, this will allow SRK to give the long
holes a much wider sphere of influence in a future NI 43-101 resource
report, Silver Bull added.
"When we consider that the drills will be starting off underground in
high grade silver mineralization, and drilling in an area with a
tremendous amount of historical work which already defines this zone we
see this as a very low risk program which should add both silver ounces
to the deposit, and increase the overall grade within the Shallow Silver
Zone," said president and CEO Tim Barry.
The company noted the three goals of the 3,000 metre drilling program
are to increase the confidence of the historical long-hole data set,
define the extents of the ore body, and infill any gaps that exist in
the historical data set.
"This will also be extremely cost effective as we will be using our
own drills to do this work and there is very little preparation that
needs to be done to the underground workings," added Barry.
The 3,000 metre underground drill program will initially pick 5 or 6
stations within the high grade zone and "twin" the surrounding long
holes for a direct assay comparison.
Because much of the high grade zinc resource seen at Sierra Mojada
has also been defined with long holes and channel samples, this same
approach of twinning selected long holes will eventually be applied to
the high grade zinc mineralization at the site - which sits next to and
immediately below the Shallow Silver Zone, Silver Bull said.
The Shallow Silver Zone is an oxide silver deposit hosted along an
east-west trending fracture-karst system set in a cretaceous
The mineralized body averages between 30 to 120 metres thick, up to
200 metres wide and has 3.688 million tonnes of measured silver
mineralization at an average grade of 57 g/t, 45.175 million tonnes of
indicated silver with an average grade of 45 g/t, and 8.162 million
tonnes of inferred silver with an average grade of 40 g/t, all at a 15
The zone, which remains open to the east and west, has a 3.8
kilometre strike length, of which roughly 60 per cent is at or near
A significant zinc oxide body of 997 million pounds of zinc in the
measured and indicated category, and 108 million pounds of zinc in the
inferred category lies just next to, and directly underneath the silver
There is also an exploration zinc extension target estimated at
between 4 to 6 million tonnes grading between 8 to 8.4 per cent, at the
eastern end of the zinc mineralization.
The exploration target has been defined by historical data containing
3,733 channels and 1,045 long holes and comprises 70 per cent of the
data within these zinc zones, but has too few drill holes to delineate a
Silver Bull is also continuing with its metallurgical program at the
project, as well as with mapping and prospecting a number of the
Dormidos and Palomas Negros targets.
"In light of the current difficult market conditions and the low cost
of the underground program, management has decided to suspend its
surface drilling program for the moment," the company concluded.
This drilling had been targeting the extensions of the Shallow Silver
Zone to the west and the north as well as a number of near resource
Silver Bull's flagship Sierra Mojada project is located 150
kilometers north of the city of Torreon in Coahuila, Mexico. The company
also owns three mineral exploration licenses in Gabon, Africa, two of
which are currently under joint venture with AngloGold Ashanti (NYSE:AU).
These licenses are prospective for gold, manganese, and iron ore.