Tepal Project

Click for more information



Mine TypeOpen Pit
StagePreliminary Economic Assessment
  • Gold
  • Copper
  • Silver
  • Molybdenum
Mining Method
  • Truck & Shovel / Loader
Mine Life... Lock
ShapshotTepal is a large project that contains a significant potential open-pitable mineral resource. Tepal’s current NI 43-101 Mineral Resource Estimate comprises over 4 million gold- equivalent ounces in the Measured & Indicated categories, with potential to add ounces and improve grade in structurally-controlled epithermal zones.


Defiance Silver Corp. 100 % Indirect
As a result of the acquisition of Valoro Resources Inc. (“Valoro”) in fiscal 2019, the Company acquired a 100% right, title and interest in mining claims located in the state of Michoacán, Mexico (the “Tepal Project”).



- subscription is required.

Deposit type

  • Porphyry


Mineralization on the Property is characteristic of porphyry copper-gold mineralization. Porphyry-type deposits in Mexico occur in a northwest trending belt 2,800 km long on the west side of the country, following the Pacific continental margin (Sillitoe, 1976). The belt is located in the Sonoran Basin and Range, Sierra Madre Occidental and Sierra Madre del Sur covering the states of Sonora, Sinaloa, Chihuahua, Durango and Michoacán.

Mineralization on the Property consists of structurally controlled zones of stockwork and disseminated sulphide mineralization that are hosted entirely within a multi-phase tonalite intrusive complex. These sulphide-bearing zones contain significant concentrations of copper and gold with lesser silver and molybdenum values. The current resources are hosted in three distinct zones: the relatively high-grade North and South Zones and the lower grade Tizate Zone.

Morphologically, two of the zones, the North and Tizate Zones, are crudely tabular with shallow to moderate dips. Both have rough dimensions of approximately 1,100 by 600 m and thicknesses of up to 200 m. The South Zone has a smaller footprint, 600 by 500 m, but a greater vertical extent of up to 400 m, although this is possibly the result of faulting.

In the North and South Zones some generations of veins within the structural deposits display a prominent 325° to 350° orientation parallel to the north-northwest fault trend. Dips are generally vertical to steep either east or west. Other prominent orientations are also present including a set with a near east-west orientation and moderate southerly dip. The attitude of vein sets in the Tizate Zone has not yet been accurately determined; however, consistent core to vein angles in drill holes suggest several persistent orientations. The strong preferred orientation of these veins and evidence of shearing suggests development of the zones was during late magmatic stages (Shonk, 1994).

There is an oxide horizon and a narrow transition layer present in the deposits on the Tepal Property above the sulphide mineralization. The depth of oxidation ranges from 20 to 40 m on the hilltops and 0 to 20 m in the drainages. Minerals in the oxidized zone include malachite, chalcocite, minor azurite, tenorite and minor chrysocolla. Shonk (1994) indicated that a thin supergene-enriched layer exists locally at the base of the oxide horizon and consists of chalcocite and covellite coatings on sulphide grains and local areas of poddy, massive chalcocite. While minor chalcocite has been noted in drill core, drill hole assays do not indicate any leaching of copper from the oxide horizon and no local copper enrichment zones at the oxide-sulphide interface. The transition zone may be up to 15 m thick; however, it is usually significantly less than this and in some cases is absent altogether. The transition is identified by the overlapping presence of iron oxides and sulphide mineralization.

Primary sulphide mineralization consists dominantly of disseminated and stockwork-controlled chalcopyrite and pyrite with minor, locally significant pyrrhotite, bornite, sphalerite, molybdenite and galena. The highest grade mineralization is associated with low total sulphide contents and low pyrite: chalcopyrite ratios.

Micron-sized native gold is usually associated with the chalcopyrite either as grains attached to the surface or fracture fillings within copper sulphides (Duesing, 1973), although free grains can also occur. Hypogene sulphide mineralization typically occurs as irregular individual sulphide grains or interstitial patches of pyrite- chalcopyrite-bornite within the granular, altered tonalite porphyry groundmass, often associated with growth of granular quartz in the groundmass, as chalcopyrite-pyrite veinlets and as quartz-hydrobiotite/Fe-chlorite-pyrite-chalcopyrite veinlets associated with sericite-hydrobiotite/Fe-chlorite-pyrite-quartz alteration (Shonk, 1994).

Intensity of mineralization is strongly related to the presence of late magmatic quartz and the density of late magmatic veining (Shonk 1994). Both the North and South Zones have a crude zonation with a gold-rich core associated with the highest gold and copper values and highest Au: Cu ratios to a copper dominant periphery with lower Au: Cu ratios and then to a barren pyritic halo (Shonk, 1994). Silver and molybdenum values are also somewhat elevated in the core areas but distribution is more erratic and is not always coincident with Au or Cu values. In particular Mo often seems to occur with elevated values in the North and South Zones over short drill hole assay intervals, perhaps due to specific structural controls.

In the Tizate Zone, copper values are on average slightly lower than the North and South Zone averages and gold grades are significantly lower. Grade distribution however is very even and the very high-grade cores and lower grade fringes seen at the other deposits are not seen here. Both the Ag and Mo values are significantly higher than in the other deposits and they show greater coincidence with Au and Cu, particularly with respect to Mo.

Mineralization on the Property is characterized by strongly anomalous Cu, Au, Ag, Zn, and Mo and more erratic and weakly anomalous Pb, Mn, Bi, and As. Unfortunately, inter-element relationships have not been systematically analyzed over the mineralized zones because the Teck soil sampling program, which covers the core of the Property, and most Teck drill core samples were both only analyzed for Cu and Au. Anomalous levels of As, Pb and Zn have been encountered in recent drilling which have full Inductively Coupled Plasma (ICP) data. In most cases, elevated levels of these elements occur erratically in veins and mineralized structures or areas outside of the deposits.



- subscription is required.

Mining Methods


- subscription is required.


Crushers and Mills


- subscription is required.



- subscription is required.


CommodityProductUnitsAvg. AnnualLOM
Gold Metal in conc./ doré koz 79766
Copper Metal in concentrate M lbs 32308
Copper Concentrate kt 554
Silver Metal in conc./ doré koz 2522,458

Operational metrics

Daily mining rate 37.5 kt *
Daily processing rate 26.4 kt *
Daily processing capacity 27,500 t *
Annual processing rate 9.6 Mt *
Stripping / waste ratio 0.6 *
Waste tonnes, LOM 52,464 kt *
Ore tonnes mined, LOM 90,479 kt *
Total tonnes mined, LOM 142,943 kt *
Tonnes processed, LOM 90,479 kt *
* According to 2017 study.

Production Costs

Cash costs Gold USD 313 / oz * **  
All-in sustaining costs (AISC) Copper USD 0.38 / lb * **  
All-in sustaining costs (AISC) Gold USD 396 / oz * **  
Assumed price Copper USD 2.5 / oz *  
Assumed price Silver USD 18 / oz *  
Assumed price Gold USD 1,250 / oz *  
* According to 2017 study / presentation.
** Net of By-Product.

Operating Costs

OP mining costs ($/t mined) USD 2.16 *  
OP mining costs ($/t milled) USD  ....  Subscribe
G&A ($/t milled) USD  ....  Subscribe
Total operating costs ($/t milled) USD  ....  Subscribe
* According to 2017 study.

Project Costs

MetricsUnitsLOM Total
Pre-Production capital costs $M USD  ......  Subscribe
Sustaining CapEx $M USD  ......  Subscribe
Closure costs $M USD  ......  Subscribe
Total CapEx $M USD  ......  Subscribe
OP OpEx $M USD  ......  Subscribe
Processing OpEx $M USD 506.9
G&A costs $M USD 67.4
Total OpEx $M USD  ......  Subscribe
Total Taxes $M USD  ......  Subscribe
Royalty payments $M USD  ......  Subscribe
Net revenue (LOM) $M USD  ......  Subscribe
Pre-tax Cash Flow (LOM) $M USD  ......  Subscribe
After-tax Cash Flow (LOM) $M USD  ......  Subscribe
Pre-tax NPV @ 5% $M USD  ......  Subscribe
Pre-tax NPV @ 10% $M USD  ......  Subscribe
Pre-tax NPV @ 8% $M USD  ......  Subscribe
After-tax NPV @ 5% $M USD  ......  Subscribe
After-tax NPV @ 10% $M USD  ......  Subscribe
After-tax NPV @ 8% $M USD  ......  Subscribe
Pre-tax IRR, %  ......  Subscribe
After-tax IRR, %  ......  Subscribe
Pre-tax payback period, years  ......  Subscribe
After-tax payback period, years  ......  Subscribe

Heavy Mobile Equipment


- subscription is required.


Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Feb 24, 2017
....................... Subscription required ....................... Subscription required Subscription required Feb 1, 2023

EmployeesContractorsTotal WorkforceYear
...... Subscription required ...... Subscription required ...... Subscription required 2017


- subscription is required.