CIM Compliant Resource

The NI 43-101 compliant mineral resource released December 14, 2012 was estimated by ACA Howe International Limited (“ACA Howe”) using historical diamond drilling results that were verified by analyses of stored core and pulp samples. The mineral resource is based on approximately 58,100 meters of historical diamond drilling at the Boh Yai and Song Toh mines and consists of 2,895,500 tonnes with an average grade of 8.91% Pbeq and Indicated and 1,955,000 tonnes Inferred with an average grade of 7.68% Pbeq. The mineral resources were estimated by Rick Parker, FGS, MIMMM C. Eng., Consulting Geologist with ACA Howe. Mr. Parker is a Qualified Person for the purposes of National Instrument 43-101 Standards of Disclosure for Mineral Projects of the Canadian Securities Administrators, and has verified the data disclosed in this release.

ACA Howe concluded that:

  • The Song Toh and Boh Yai deposits have demonstrated the potential to support continuous production and to exceed the historically reported resources at a similar grade during mining operations,
  • There is considered to be significant potential to develop additional resources along or across strike of the presently defined zones and at depth below currently known mineralization, and
  • Exploration potential on much of the property surrounding the mines remains largely untested.
Boh Yai and Song Toh resources by deposit (cut-off grade 3% Pbeq)
Deposit Class Tonnes Pbeq, % Pb, % Zn, % Ag,  g/t
Boh Yai Indicated 2,138,000 9.14 3.12 3.49 73.84
Song Toh Sw Indicated 318,000 6.23 2.84 0.25 87.27
Song Toh Camp Indicated 439,000 9.69 6.29 1.42 56.13
Total Indicated 2,896,000 8.91 3.57 2.82 72.63
Boh Yai Inferred 1,643,000 7.20 2.36 3.37 44.10
Song Toh Sw Inferred 179,000 7.58 4.70 0.05 78.35
Song Toh Camp Inferred 133,000 13.67 7.80 3.53 68.40
Total Inferred 1,955,000 7.68 2.95 3.08 48.89


  • Mineral resources which are not mineral reserves do not have demonstrated economic viability. The estimate of mineral resources may be materially affected by environmental, permitting, legal, title, taxation, socio-political, marketing, or other relevant issues.
  • The database used by ACA Howe for the resource estimate contains 3,914 Pb, Zn and Ag assay results from 551 surface and underground diamond drill holes (total of 58,078 metres). Samples were assayed historically by the mine laboratory at Song Toh with check samples by SGS. A representative number of core and pulp samples that were analysed in 2012 by ALS provided verification of the historical assays.
  • Lead Equivalent – Pbeq – was calculated using prices of US$0.93/lb lead, US$0.90/lb zinc, and US$ 23.03/oz silver, (with no provision for metallurgical recoveries). The formula used was Pbeq% = Pb% + 0.962Zn (%) + 0.0360Ag (g/t). Small discrepancies may exist due to rounding errors.
  • Mineralised domains were modeled with the aid of drill results and detailed interpretations of geology recorded on historical plans. A total of 42 individual domains was identified, including 28 at the Boh Yai deposit 9 at the Song Toh SW deposit and 5 at the Song Toh Camp deposit.
  • Micromine block models with block cell dimensions of 4.0 metres and sub blocks of 2.0 metres were coded to reflect surface topography and geology. Metal values from 1.0 metre drill composites were interpolated to block models using Inverse Distance Squared weighting (IDW2) according to parameters and search ellipsoids established from analysis of the variography within each domain. A three-pass approach was used to interpolate metal into the blocks. A density factor of 2.9 t/m3 was assigned to all mineralized domains based on historical measurements of specific gravity. For resource classification, 2 drill holes with 3 composites and a search distance less than the range were required for Indicated category, remaining blocks were assigned to Inferred category.