The 2016 exploration program at Citadel has initially been...

The 2016 exploration program at Citadel has initially been divided into two phases.

During the first phase Antipa will conduct IP ground geophysical surveys at 16 high-priority targets within an extensive 400 square kilometre region of the Citadel Project, including Calibre, Magnum, Corker, Meekus and the broader Rimfire area.
Induced Polarisation (IP) is a technique of measuring an induced potential field in the ground in order to map the geological subsurface. From measurements of the induced potential field the chargeability and resistivity of the subsurface can be calculated.These measurements are made in either the time domain or frequency domain using various configurations of transmission electrodes and multiple potentiometer receivers. IP and resistivity surveys can be used to detect and map economic mineral deposits, in particular those associated with disseminated sulphides and massive sulphide mineralisation. One of the major strengths of IP is that the technique is sensitive enough to detect disseminated sulphides which are often not measurable with EM systems. IP has been used to map many types of deposits including porphyry copper, gold bearing sulphides, manganese and titanium bearing placers.
The two techniques that are used in IP surveys are Time Domain and Frequency Domain. Time domain IP involves transmitting current into the ground and then switching it off. The current flow induces a potential field which the receivers measure during the on and off time. The voltage peaks during the on-time and begins to decay as soon as the current is switched off. From the on-time peak voltage measurement the apparent resistivity can be calculated. Chargeability is calculated from the off-time measurements of the transient voltage decay. In frequency domain IP an alternating current is transmitted into the ground at a low frequency which induces a potential field in the subsurface. The receivers measure the phase shift in the signal and from this the chargeability and resistivity can be calculated.

Second phase of the exploration program will be driven by the results of phase 1 and is expected to include reverse circulation drill testing of IP chargeability anomalies generated during phase 1 and possible follow-up geophysical surveys.
Reverse circulation (RC) drilling uses a bit attached to a down-hole hammer to produce a hole. Unlike diamond drilling, RC drilling produces samples of rock cuttings rather than a sample of rock core. The down-hole hammer is powered by compressed air, which also acts as the medium bringing the drill cuttings up to surface.
RC drilling today produces samples of high quality and reliability. Dual-pipe RC drilling utilizes double drill rods where air is passed down the hole through the outside annulus and into the hammer. Drill cuttings are cleared from the bit by the air and travel up through the centre tube of the drill rods remaining free from contamination.
RC drilling results are successfully used in compliant (NI 43-101, JORC) resource calculations worldwide. The method is unbeatable in areas where water is scarce or expensive, such as Australia.
A big advantage of RC is its high rate of penetration. Penetration rates often exceed 80 m per shift depending on ground conditions. The speed of drilling can often mean big cost savings compared to slower drilling methods.