A NEW MINING CAMP DISCOVERED WITH BEEP MATS AND INFINITEM. A new copper-zinc mining camp (Gaumont, 2007) is being presently drilled off in central Quebec by Breakwater and Virginia Gold. Two new techniques contributed to the discovery. Introduction The project began in 2003 (Robertson, 2004) when a Virginia geologist spotted a gossan from a plane in an area mapped as paragneiss and sediments. A geological crew sent in August to examine the gossan noted favourable formations but samples collected on this first visit returned no economical values. In September a Beep Mat crew sent to cover the area surrounding the gossan discovered about a dozen bedrock conductors. Trenches dug and blasted on the first two Beep Mat conductors turned out to be barren sulphides but samples from the third site (Archer, 2007) assayed 22.4% zinc. The majority of the remaining conductive sub-outcrops sampled by that first Beep Mat crew returned also ore grade material. A VTEM survey covered right away the area and discovered many, many conductors. Ground MaxMin and diamond drilling followed shortly afterwards on those conductors where sampling in shallow trenches localised by the Beep Mats indicated values. Upon making the discovery Virginia staked the whole favourable belt. By the end of the winter of 2004 the Coulomb project covered 65 sq. km, and diamond drilling had indicated the presence of three promising massive sulphide lenses. In the following years Beep Mat crews checked all the VTEM targets, and they collected near surface samples of the conductors from most of them. Pulse EM surveys was also widely used to define deeper drilling targets. A second new technique used by Virginia led to the discovery of a fourth copper zinc lens by the InfiniTEM pulse system survey developed by Abitibi Geophysics. A fifth lens was discovered by geologists reinterpreting drilling results. In a proven mining camp, the odds to discover a new hidden orebody are high, so even deep geophysical targets warrant to be drilled. Elsewhere, the barren conductors are so numerous that it is more cost effective to pre-select them with the Beep Mat. Actually the odds are so low that there are millions of known EM conductors, both airborne and ground that no one even walked over. In this potential mining camp it took only two years for the InfiniTEM to discover the first ore lens too deep to be detected by an airborne VTEM, but a quarter century elapsed and thousands of either barren or weakly mineralised conductors were sampled across most of Canada before the Beep Mat contributed for the first time to the discovery of this new mining camp. The difference could be explained if one accepts the existence of isolated mining camps separated by numerous areas of barren conductors. If so, both techniques should have a bright future. To further illustrate how orebodies occur grouped, in the Coulon Project none of the numerous conductors sampled by the Beep Mats away from the five lenses appear to have warranted any extensive drilling.
The position of the lenses of massive sulphides is illustrated below. Presently Breakwater Resources are earning a 50% interest in the property upon spending 6,5 millions $ CA in exploration. So what is a Beep Mat This powerful miniaturized electromagnetic survey instrument instantly detects conductive and magnetic outcrops or boulders hidden under up to 4.5 meters of overburden or snow. With the new BM8, one can now store data for a whole day.the programmable module may for example records every tenth of a second the detected intensity of any conductor, a factor defining the conductivity of the material detected, and finally a signal detecting any magnetite present near the sensor. If one connects a GPS with an outside antenna, the Beep Mat will also record once every second the position of the operator.
One can the plot the traverses of a day, and thus show the path of the operator. The profiles show also the intensities of the three signals on a map of all the bodies detected. The sensors exist in two sizes; the smaller size to be pulled through the bush by a single operator, the large size can either be carried by two men, or be pulled by a skidoo on the snow or by an ATV. The operator can be also be warned by distinct sound whether a conductor, or magnetite, or both are detected, the stronger the signal the louder is the sound. A walking mag can also be simultaneously recorded. Why use Beep Mats Beep Mats detect the same substances as any airborne or ground EM surveys, but with some specific advantages and disadvantages. The main advantage is that when a conductor is detected, it can be examined, sampled and assayed. In a large project in the shield the cost per conductor thus examined is usually about $2000 or less than 2% of the cost of an isolated DDH, so with the same follow up budget one will examine up to 50 times as many targets. For example, after examining most of the airborne targe ts with Beep mats, Virginia was able to concentrate their DDH on deep conductors in the vicinity of known mineralizations, rather than testing just as valid conductors further away, that the Beep Mat crew suggested being of less interest. Beep Mats do not react to all valuable showings: some orebodies, even of massive sulfides, may be detected only by IP surveys. But even in those circumstances, Beep mats can sometimes help: a
float of sulfides may contain enough pyrrhotite to be detected, even if there is too little pyrrhotite to allow the main body to be detected from a plane. Along the same lines, Ex-In detected surface copper veins at the Opemisca mine, even if they did not react to a regular MaxMin survey. Where to use Beep Mats Areas covered by shallow glacial till are the usual environment for Beep Mats. For the southern half of Quebec excellent glacial maps prepared for the forestry operators allow to preselect where to prospect. But even without them, Beep Mats are still most effective when used by properly trained and motivated crews. In Canada, where outcrops are frequent, Beep Mat operators also often report rusty gossans and even fresh sulfides. From my experience, first nation crews are especially effective to note and report such non-conductive but interesting sulfides. In the rest of the world, areas of active erosion yielded excellent results, both for boulders and for outcrops. Pictures from Turkey province bordering the Black Sea illustrate some local successes. Falconbridge was also successful in using Beep Mats in hilly areas of Vietnam.
In arid climates, such as along the ocean coast of Peru, Beep Mats were successful in detecting gossans hidden under more than two meters of sand and rocks. What are the misgivings Up to recently the Beep Mat did not record the position of the operator, so that the geologist in charge of the project had no control of the operators, nor he could be secure that a given target had been adequately surveyed. Today, geologists can check exactly where the operator went and what the instrument recorded, thanks to the gigantic digital memories available today, which Instrumentation GDD inc. incorporated in the Beep Mats. The other misgiving is that some geologists feel that they loose any credit to any discovery made by such a simple instrument. If Virginia was a reference, they sure got all rewarded even if the Beep Mats contributed to the discovery. It is an awful waste of good work when recently a huge 10 000 000 $ survey in northern Quebec, by a major mining company consisting of high quality airborne EM, Mag, geochemistry ground geophysics, etc, was followed up by only by two sites being drilled, under showings found, trenched and drilled and I even visited these two showings back in 1954. Even if no targets warranted the cost of a DDH, hundreds of conductors could have been surface sampled with a minimal additional budget. Who knows what could have been found. For over forty years I have heard talks saying that surface mines have all been found, that one has to look deep. Just to mention a few, in that period Canada has seen discoveries of Kidd Creek (massive chalco under five feet of moss) Hemlo, where mining started at the surface under two inches of moss, Doyon, an open pit one mile long in the heart of the Rouyn Val d'or gold districts hidden along half a mile under less than five feet of till, and let s not forget Voisey Bay, a gossan visible from a helicopter 5 kilometers away, and noted on geological maps as barren pyrite. So there are still lots of valuable orebodies that lay close to the surface waiting to be discovered in Canada, even next to old mines. A fantastic new discoveries may have already been made and might hit the news this year.
Is the Beep Mat a proven technology? Yes, Inco mine managers in Sudbury has put them on conveyors to watch in real time the nickel ore grade being sent to the mill. Apparently, since then, no more mistake occur of sending waste in the ore pass. Ore grade estimation in real time at Inco Sudbury. Beep Mat located on the conveyor right after crusher References Robertson, R. 2004, Virginia makes VMS find in Quebec: The Northern Miner, Volume 90, No 12, May 14-20. Archer, P., C. Chapdelaine and F. Huot, 2004, Discovery of High-Grade Metamorphic Volcanogenic Massive Sulfides in the Coulon Belt, James Bay region, Quebec Exploration 2004, MRNF, Quebec. Archer, P. 2007, Verbal communications. Gaumond, A, P. Archer, and A. Laliberté, 2007, Projet Coulon JV, http://www.virginia.qc.ca/ajouts/communiques/2007/11juillet_fr,htm