Val d’Or, Que. — Exploration is at a high in the Abitibi district of Quebec, and among the most active companies is
The latest drilling at the Lac Herbin property cut a new zone (zone 2), parallel to the Main zone. Highlights include a 3.6-metre intercept that graded 63.6 grams gold per tonne. Another hole hit 2.8 metres grading 20.8 grams gold. Other intercepts graded from 3.9 to 18.9 grams gold over 1.4-4.7 metres.
True width is estimated to be 80-100% of the down-hole widths.
Zone 2 is 150 metres southwest of the Lac Herbin zone, which constituted most of the estimated inferred resource of 670,000 tonnes grading 6.4 grams gold per tonne calculated earlier this year. Zone 2 has been tested over a 160-metre strike and a similar length of dip, and is centred at a vertical depth of 250 metres.
Fourteen holes were drilled in the area of the new zone. Higher-grade gold is found along, or near, the intersection of shear zones.
A shear zone farther south returned significant gold values, including one hole that hit 4.4 grams over 6.6 metres. This intersection included 2.6 metres grading 9.89 grams gold. Thirty metres lower in the hole, a 1.5-metre intercept graded 11.25 grams gold.
Gold has also been intersected in tensional veins that crosscut the shears. These were identified in several holes, three of which returned grades of 13-92 grams gold over widths of 0.5-0.8 metre.
Eight holes tested the eastern and western extensions of the Lac Herbin shear zone. One kilometre to the east, the structure was intersected; the best intercept was 0.8 metre wide grading 4.5 grams gold per tonne. Widely spaced holes to the west cut the structure but did not hit significant gold. Following the latest drill program, a new resource will be calculated.
The core appears to be siliceous, fractured and intersected by white quartz veins with local pyrite lenses, and by quartz-tourmaline veins.
Richard Roy, a consulting geologist with Alexis, sums up the program: “At Lac Herbin, the hit ratio on the zone has been about twenty per cent. Even when you are underground defining gold in stopes at Ferdeber and Dumont, both of which are in a similar geological environment, this is about the same rate — twenty to thirty per cent — that producing gold properties have seen. You can go underground and drill at a much tighter spacing, or you delay and continue drilling from surface. That decision will have to be made in the upcoming months. We expect that, once underground, more ore will be found. The history of these deposits is always like that.”
Roy worked at the Dumont mine, 1 km southwest of the Lac Herbin zone, in the 1990s and on the initial discovery of Lac Herbin. Dumont produced 1.2 million tonnes grading 6.5 grams gold per tonne in total, whereas the Ferdeber mine, 2 km to the east, turned out 1.6 million tonnes at 7 grams gold. Lac Herbin was drilled in the mid-1990s, and a resource of 400,000 tons grading 0.21 oz. gold per ton was calculated. The construction of a portal began and ramp development was planned, but work was halted in response to the low gold price, and money dried up when the Bre-X scandal broke. The property lay idle.
Gold is associated with quartz-pyrite veins in shears that cut the Bourlamaque batholoith. The gold is primarily in pyrite. In general, 2% pyrite equates to a grade of 0.2 oz. per ton (this is what was used underground for grade control at the nearby mines, and it worked well). Free gold is rare.
Alexis is relatively new to the region, so it has teamed up with companies and personnel who have experience in the Abitibi camp.
In 2003,
Timing was propitious: in the fall of last year, Aur decided to shut down its exploration office in Val d’Or, and Alexis was able to hire several of the exploration team on contract.
Early in 2004, drilling began at Lac Herbin and on the Cadillac option. By April, further volcanogenic massive sulphide (VMS) targets were picked up from Aur. The land package in the Val d’Or area covers 270 sq. km. Since Alexis acquired the Aurbel property, about 18,000 metres have been drilled. Roughly 15,000 metres have been drilled on the Cadillac option and 15,000 metres are being drilled on the VMS properties.
Lac Herbin is about 10 km east of Val d’Or, and what seems like a stone’s throw (actually about 2 km) from the 1,400-ton-per-day Aurbel mill, which is dormant (Alexis has negotiated an option to buy it).
Cadillac Break
Alain Carrier of the consulting firm InnovExplo is supervising work on the Cadillac properties optioned from Aur.
Gold targets in the Cadillac region consist principally of quartz-tourmaline veins associated with shear zones, gold associated with pyrite in ultramafic rocks, and skarn-hosted gold and gold-copper deposits. More than one deposit type can be superimposed on another.
On Alexis’s property, one finds local clastic sedimentary horizons that are highly silicified with epidote and iron carbonate, pyrite, chalcopyrite, magnetite and garnet — typical mineral assemblages of skarn deposits.
Eight mineralized areas have been found over a 12-km strike of skarn environment. Sixteen induced-polarization (IP) and Megatem anomalies have been located. One of these, the Hogg showing, 10 km southeast of Val d’Or, was drilled in October.
Assays from the first hole are highlighted by a 3.8-metre intersection grading 21.2 grams gold and 0.56% copper (estimated true width is 3.2 metres) at 66 metres down-hole. This includes a 2.1-metre intercept of 35.6 grams gold per tonne and 0.81% copper.
Assays are pending from two holes drilled along strike and down-plunge of this hole.
Mineralized lenses are oblate and elliptical in shape and have limited surficial extent (about 20 metres along strike).
The recognition of a skarn setting in the Abitibi is something new, and Alexis is using the model to target exploration. In doing so, Philippe Cloutier, a consulting geologist managing Alexis’s exploration, acknowledges that Alexis is able to tap into significant government funding to stretch its exploration dollars.
A major intrusion in the Cadillac Break area is the East Sullivan stock, a late alkaline intrusion with peripheral dykes that have alteration haloes of hornfels and local skarn mineralization.
The skarns are commonly associated with north-northeast faults and are associated with breccia zones, with magnetite and chalcopyrite filling the matrix. Both pyrite and chalcopyrite veinlets form a complex network.
According to the Aur Resources option agreement, Alexis can earn a half-interest in the properties by paying $250,000 to Aur annually in March 2004 and 2005, and by spending $5 million on the property by the end of March 2006. Alexis can choose to acquire the remaining half-interest over 90 days subsequent to March 31, 2006. The land package covers the past-producing Louvem, Ferdeber, Dumont and Bevcon mine properties.
Noranda joint venture
In June of this year,
In September, drilling led to the discovery of the Norelex deposit, 10 km northwest of the Doyon mine. Two holes were drilled; the first cut 33 metres grading 2 grams gold per tonne at a down-hole depth of 354 metres in a sericite-ankerite altered tonalite. Within this interval is a 0.9-metre intercept of 20.4 grams gold. Gold was seen in pyritic quartz veins.
There had been no holes within a 5-km-radius of the discovery, and there is little outcrop and minimal geophysics, so drilling was halted to allow for magnetic and IP surveys.
Alexis hopes to visit Cambior’s Doyon mine to learn more about its geology, as the tonalite looks similar to Cambior’s ore. Cambior has worked the deposit for more than 50 years.
With the help of Alexis, Noranda is exploring the region. Between 55% and 60% of the 3-year, $16.5-million base metal exploration budget Alexis is providing will be spent on drilling. Alexis is earning a 50% interest in these properties. Although Noranda personnel have extensive experience with VMS, they also have gold experience, and both companies are using their experience to mutual benefit. The Val d’Or and Rouyn offices communicate daily.
“Noranda was not in a position to drill a lot of its targets, because it is such a large company competing with other exploration teams worldwide for a budget,” says Cloutier. “Fortunately for Alexis, it walked in and Noranda had just completed its three-D Gocad modelling of the Rouyn camp. There is no lost time and money on generating targets.” (Aur Resources had also completed a similar model for the Val d’Or camp.)
Two holes were recently drilled to test MegaTem anomalies on the Lac Montbray property, 25 km west of the Horne smelter in Rouyn-Noranda, resulting in the discovery of a massive sulphide horizon.
The discovery hole cut 5.2 metres grading 5.6% copper and 1.7% zinc, plus 0.3 gram gold and 17.6 grams silver per tonne, at a vertical depth of 110 metres. The hole was designed to test a strong off-hole anomaly encountered in the drill program’s first hole, 50 metres to the west. That hole encountered a VMS zone with only anomalous metal values.
Massive sulphide mineralization consists of 70% pyrite, 20% chalcopyrite, 5% sphalerite, and 5% chloritic host rock and quartz. The mineralization marks the contact between overlying andesites and underlying felsic volcanic rocks. The zone remains open to the east and at depth.
Assay results from a wider zone of sulphide-filled breccia and stringer mineralization within the footwall to the massive mineralization are pending. The area has seen little previous work, and has not been drilled; a third hole is under way 50 metres east and down-dip of the discovery hole.
Noranda needs future feed for its smelter. Roads make it accessible. The major has trained personnel, and there is a huge historic database. The joint venture is targeting a variety of deposits and is being systematic, following along favourable horizons and structures. They are looking at old data and trying to see if past drilling may have cut the edge or alteration halo of a mineralized zone. Holes that have ended in alteration may be deepened to try to locate the source of the alteration.
It has taken several years to enter all the data into the Gocad system. Gocad integrates geological, geochemical and geophysical data in one system, allowing for manipulation and compilation that can be queried. A large part of the camp was compiled along 200-metre spaced sections with checks to verify that the geology coincided in three dimensions. Most of the information that has been entered is in a 17.7-by-17.8-km area deemed the central camp. The data is primarily within 1 km of surface. Over 11,000 drillholes pierce this central area. To date, results from 19,000 drill holes and 100,000 samples have been entered, along with geological and geophysical information. The program can assign a zone of influence to a structure, such as a fault, assisting in targeting drill holes. A 40-by-70-km area covering the Blake River group is in the works. By the end of the year, the companies expect to be able to start manipulating the additional data to generate even more targets.
Geophysics
A regional airborne MegaTem survey, in conjunction with an airborne magnetic survey, was completed two years ago, and some follow-up has been done. Lines were flown in a north-south direction at 150-metre spacing in some blocks and at 200-metre spacing in others. The system is capable of detecting deposits 200-250 metres (and in some cases as deep as 300 metres) below surface. The company is learning through experience that the largest anomalies are not necessarily the best. Follow-up ground geophysics is done prior to drilling, and down-hole geophysics sometimes follows drilling.
Mario Masson, senior exploration geologist with Noranda, uses the Perseverance zinc deposit, 6 km northwest of Matagami, as an example of how exploration can succeed through the use of new technology. The MegaTem anomalies are distinctly clearer than anomalies recorded in 1983. One hole drilled in 1981 missed the deposit by about 5 metres. The main lense is only about 50 metres below surface, so depth was not a mitigating factor.
In 2000, the first hole Noranda drilled was centred on the anomaly, yet it missed the deposit. Geophysics suggested it plunged toward the west, and the second hole was successful. The deposit comprises three lenses with an estimated reserve of 5.1 million tonnes grading 15.8% zinc and 1.2% copper, plus 29 grams silver and 0.4 gram gold per tonne.
IP surveys are testing some areas at depth. The geophysical firm Quantec is using a 2.5-km line length, which reads up to a depth of about 1 km. Quantec collects the resistivity and chargeability data during the day, and magnetotelluric data during the night. The system has been tested on known deposits, and it has detected alteration haloes around massive sulphide deposits, as well as the deposits themselves.
Noranda holds about 800 sq. km in the region, much of which is underlain by the Blake River rocks, which have hosted numerous large deposits. By the end of this year, 15,000-20,000 metres of drilling will have tested several prospective targets. At presstime, six drill rigs were turning on the Noranda options and four on the Val d’Or properties.
The Alexis-Noranda option is not exclusively geared to VMS exploration but allows Alexis to explore for gold on the properties and spend $3 million on those efforts for an opportunity to earn a 65% interest in any such find. The land package includes mineral rights over eight past-producing mines, namely Horne, Quemont, Amulet, Gallen, Ansil, Newbec, East Waite and Old Waite.
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