Dec 20 2016
Aurvista Gold Corporation ("Aurvista" or the "Company") is pleased to announce the start of a ground UTEM-5 Geophysical Survey (the "Survey") on the Douay Gold Project ("Douay"). Lamontagne Geophysics Ltd., of Kingston, Ontario, will initiate and complete the Survey over the next month on the most significant bedrock conductors at Douay: Anomalies "E", "F" and "G". Results will be made available by mid-Q1-2017.
As previously reported by Aurvista in August 2016, the Company had completed a 1,421 line-km airborne helicopter magnetic, time-domain electromagnetic ("TDEM") and radiometric survey. The TDEM survey outlined 7 strong near surface conductive bedrock anomalies ("A" to "G"), all associated to the strongest EM-INPUT™ anomalies, 4 in proximity to the Casa Berardi Deformation Zone ("A" to "D"), NW of the Adam Creek Gold Deposit (the "Deposit"), and 3 in proximity to, and surrounding the 'South Porphyry" ("E" to "G"), S of the Deposit. Characteristics of Anomalies "E", "F" and "G" are summarized as follows:
Anomaly "E" is the most significant since it is located in proximity to the gold bearing "Main Porphyry", the "South Porphyry" and the "Adam-Porphyry". There are chlorite-sulphide bearing "feeder pipes" nearby as observed in drill holes DO-92-24 and DO-11-34, typically found in association with massive sulphide mineralization, yet to be found at Douay. The historical drill holes DY-99-04, 05 and 06, 46878-0, 46899-9 and 0, 64487-0, 468880-0 and D-92-32 skimmed the anomaly by drilling above or holes were too short, but explained the conductive source as graphite. There is no graphite in the re-logged drill core.
Anomalies "F" and "G" are larger in size but are believed, based on nearby re-logged drill core from the Phase 1 program, to be related to sulphide mineralization. However, laminar graphite was observed in centimeter-wide shear zones in core from the Anomaly "F" area.
The UTEM Survey
(from www.lamontagnegeophysics.com)
UTEM is an acronym for University of Toronto Electro-Magnetic system. It is a wide-band time-domain electromagnetic ("EM") system, which uses a large fixed transmitter loop and a moving receiver. It is different from other EM systems in that it can detect good EM conductors in the presence of poorer ones. The UTEM system measures the EM response while the transmitter field is changing (on-time measurements). UTEM sees both the freely decaying and directly driven part of the magnetic field. It is this second aspect that makes UTEM unique and so important in detecting and characterizing extremely conductive deposits such as massive sulphides.
The field procedure consists of first laying out a large loop of a single strand insulated wire and energizing it with a current from a transmitter powered by a motor generator. The loop is either square or rectangular shaped with sides between 300 meters and 4,000 meters long. At Douay, the loops are 1,500 meters by 1,200 meters. Survey lines are generally oriented perpendicular to one side of the loop and surveying can be performed both inside and outside the loop. At Douay, readings are off loop as the targets are thought to be steeply dipping. The UTEM receiver gathers and records a number of channels of data at each station simultaneously reading all three components. The higher number channels correspond to high frequency, while the lower number channels correspond to low frequency. Therefore, poor or weak conductors will respond on higher channels. Progressively better conductors will give responses on progressively lower number channels. Massive and highly conducting sulphides or graphite will produce a response on all channels, with graphite showing more linear anomalies and massive sulphides being more compact.
Source: http://www.aurvistagold.com/en/