Ayawilca Tin Zone

Ayawilca Tin Zone

The Ayawilca Tin Zone forms flat-lying sulphide lenses at the contact of the limestone and phyllite, underlying the Zinc Zone at Central and East Ayawilca. The Tin Zone sulphide lenses consist of massive pyrrhotite with quartz, chlorite, cassiterite (an common ore mineral of tin), pyrite, and chalcopyrite. Quartz stockworks within phyllite also host tin-copper mineralization beneath the lenses.

Further metallurgical test work is required to determine the recoverability of the cassiterite mineral from the sulphide-rich mineralization.

Mineral resources at the Ayawilca Tin Zone are estimated to contain, as at November 26, 2018 (see Table 1):

  • 201 million pounds of tin in the Inferred resource category;
  • 67 million pounds of copper in the Inferred category;
  • 8 million ounces of silver in the Inferred category.

Figure 1. Long section through the 060 Fault, looking northwest, showing the manto style tin resources at Ayawilca in yellow.

    Mineral Resources

    The current resources at the Ayawilca Tin Zone, as estimated by RPA of Toronto, Canada, are highlighted in the following table.

    Table 1 – Ayawilca Tin Zone Inferred Mineral Resources as of November 26, 2018










    Tin Zones










    1. The Qualified Person for the estimate is Ms. Dorota El Rassi, P.Eng., an RPA employee. Mineral Resources have an effective date of November 26, 2018 CIM definitions were followed for Mineral Resources.
    2. Mineral Resources are reported using the 2014 CIM Definition Standards. Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability.
    3. Mineral Resources are reported above a cut-off grade of US $55 per tonne NSR value.
    4. The NSR value was based on estimated metallurgical recoveries, assumed metal prices and smelter terms, which include payable factors, treatment charges, penalties, and refining charges. Metal price assumptions were: US $9.00/lb Sn, US $2.85/lb Cu, and US $15/oz Ag. Metal recovery assumptions were: 86% Sn, 75% Cu, and 60% Ag. The NSR value for each block was calculated using the following NSR factors: US $155.21 per % Sn, US $37.59 per % Cu, and US $0.22 per gram Ag.
    5. The NSR value was calculated using the following formula: US$NSR = Sn(%)*US $155.21+Cu(%)*US $37.59+Ag(g/t)*US $0.22
    6. The SnEq value was calculated using the following formula: SnEq = NSR/US $155.21 7. Numbers may not add due to rounding.

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