Sisson Project

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Mine TypeOpen Pit
  • Tungsten
  • Molybdenum
Mining Method
  • Truck & Shovel / Loader
Mine Life... Lock
SnapshotThe Sisson Project has the potential to become a near-term critical metal producer, providing new primary supply of tungsten and molybdenum to North American, European and Asian markets.


Todd Minerals Ltd. 11.5 % Indirect
Northcliff Resources Ltd. 88.5 % Indirect
Sisson Partnership 100 % Direct
Todd Corporation (Todd) of New Zealand has an 11.5% interest and Northcliff has an 88.5% interest in the Sisson Partnership, which owns the Sisson Project.



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Deposit type

  • Hydrothermal
  • Vein / narrow vein


The Sisson deposit can be defined as an intrusion related, structurally controlled, bulk tonnage tungstenmolybdenum deposit. Deposits of this type have general hydrothermal similarities to porphyry copper deposits. These types of deposit form in convergent margin to collisional tectonic environments and are related to highly evolved granitic melts formed from continental crust.

A larger granitic pluton as a source for mineralizing hydrothermal fluids at Sisson has not been intersected by drilling thus far, but the numerous, albeit narrow, granitic dykes allow the presence of such a body to be confidently inferred at depth below the deposit.

Structures focused the ascent from depth of the intrusion derived hydrothermal fluids which formed the Sisson deposit. The physical relationship between QS and SX veins exposed in exploration Trench 1 in Zone I and the concentration of mineralization along the disrupted contact between gabbro and the Turnbull Mountain Formation suggest the possible nature of this control. Trench 1 is cut by several broadly north trending, approximately vertical QS veins that are between 0.3 m and 1.5 m in width. Kinematic indicators support long-lived to episodic, sinistral movement along the structures which host the QS veins. Sheeted arrays of northwest trending, steeply dipping, narrow SX veins, as well as fewer but larger, lensoidal quartz extension veins, form an envelope at approximately conjugate angles to the larger QS veins. Orientations obtained on 1,631 veins of all types in seven oriented geotechnical drill holes (Duncan, 2011) also show that most veins throughout the deposit form a sheeted array with northwest strike and steep southwest dip.

Mineralization in the Sisson deposit is related to several types of alteration and veins, each of which has a distinct relationship to metal introduction. The mineralization has an approximate strike length of 1,900 m, average width of 650 m and average depth of 350 m.

Early barren to weakly mineralized alteration was followed sequentially by an early stage of tungsten mineralization, an intermediate stage of molybdenum ± tungsten mineralization, and a late stage of polymetallic mineralization in which tungsten is accompanied by numerous base and trace elements. Most alteration and nearly all mineralization can be directly related to specific types of veins. The overall vein density at Sisson is only about 3% and pervasive alteration zones are spatially limited, which indicates that the hydrothermal system at Sisson had a low fluid flux.

Mineralization at Sisson occurs almost exclusively in quartz veins, fractures, and their alteration envelopes. Tungsten and molybdenum are the metals of principal economic interest, whereas several other metals, including copper, zinc, lead, arsenic, and bismuth, occur in geochemically anomalous but subeconomic concentrations.

Mineralization occurs in contiguous Zones I, II, and III and in the Ellipse Zone. Zones I and II trend approximately north from the northern end of Zone III. Zone I is hosted by the Turnbull Mountain Formation, whereas Zone II occurs in gabbro. Zones I and II are structurally controlled, up to tens of meters in width, and extend several hundred meters along strike. They are dominated by QS and SX veins and contain tungsten, copper, and associated trace elements, but lack significant molybdenum. Zone III contains the bulk of the tungsten and molybdenum resource at Sisson. It is an ovoid zone that obliquely spans the contact between gabbro and the Turnbull Mountain Formation and mineralization occurs in gabbro, volcanic, and sedimentary rocks. The highest grades of molybdenum occur in both volcanic and sedimentary rocks in the central part of Zone III, whereas the highest grades of tungsten occur on either side of the contact between gabbro and volcanic rocks in Zone III. The Ellipse Zone and the southern part of Zone III are very similar to each other and contain moderate grades of both tungsten and molybdenum. Host rocks in the southern part of Zone III are gabbro and volcanic rocks, whereas the Ellipse Zone is hosted by gabbro and quartz diorite. Mineralization diminishes very abruptly at the south end of Zone III.

The minerals of economic interest at Sisson are molybdenite, scheelite, and minor wolframite.



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Mining Methods


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Crushers and Mills


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CommodityProductUnitsAvg. AnnualLOM
Molybdenum Metal in concentrate M lbs 4.1111
WO3 Crystals kt 5.6150

Production Costs

Credits (by-product) WO3 -107.8 / mtu *  CAD
Total cash costs WO3 153.3 / mtu * **  CAD
Assumed price WO3 350 / mtu *  USD
Assumed price Molybdenum 15 / lb *  USD
* According to 2013 study / presentation.
** Net of By-Product.

Operating Costs

OP mining costs ($/t mined) CAD 2.09 *  CAD
OP mining costs ($/t milled) CAD  ....  Subscribe
Total operating costs ($/t milled) CAD  ....  Subscribe
* According to 2013 study.

Project Costs

MetricsUnitsLOM Total
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After-tax Cash Flow (LOM) $M CAD  ......  Subscribe
Pre-tax NPV @ 5% $M CAD  ......  Subscribe
Pre-tax NPV @ 10% $M CAD  ......  Subscribe
Pre-tax NPV @ 8% $M CAD  ......  Subscribe
After-tax NPV @ 5% $M CAD  ......  Subscribe
After-tax NPV @ 10% $M CAD  ......  Subscribe
After-tax NPV @ 8% $M CAD  ......  Subscribe
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Heavy Mobile Equipment


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Mine Management

Job TitleNamePhoneProfileRef. Date
....................... Subscription required ....................... Subscription required ........... Subscription required Jan 22, 2013
....................... Subscription required ....................... Subscription required Subscription required Jan 22, 2013
....................... Subscription required ....................... Subscription required Subscription required Feb 7, 2023


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