2014

Sierra Metals reports a 53.5% increase in NI 43-101 compliant mineral reserves at its Yauricocha Mine, Peru

VANCOUVER, Nov. 19, 2013 /PRNewswire/ - Sierra Metals Inc. (TSX:SMT)(BVL:SMT) ("Sierra Metals" or the "Company") is pleased to announce that Yauricocha's mineral reserves have been increased by over 2,230,000 tonnes, representing an increase of 53.5% over the previously reported mineral reserves.  The new report has an effective date of January 1, 2013. The mineral resource and mineral reserve estimate was completed by Yauricocha personnel and audited by Gustavson Associates LLC of Lakewood, Colorado ("Gustavson").

Press Release Highlights:
  • Total Proven and Probable Mineral Reserves for Yauricocha are 6,394,000 tonnes averaging 94.8 g/t silver, 2.09% lead, 0.70% copper, 2.53% zinc and 0.80 g/t gold (360.6 g/t AgEq), up from 4,163,000 tonnes at the end of 2011.
  • Total Measured and Indicated Mineral Resources for Yauricocha are 6,139,000 tonnes averaging 114 g/t silver, 2.37% lead, 1.02% copper, 3.39% zinc and 0.95 g/t gold (464.4 g/t AgEq), up from 4,181,000 tonnes at the end of 2011.
  • These results represent a 53.5% increase of over 2,230,000 tonnes in P&P Mineral Reserves, a significant increase since the previously reported NI 43-101 mineral resource estimate.
  • Yauricocha's mine life has been increased by two years to a total of seven years based on this NI 43-101 report.  The Company, however, expects to demonstrate a further increase in the mine life when the next report is completed in early 2014.


"Since the Company's acquisition of Yauricocha in 2011, proven and probable reserves have been increased by a factor of 5.6x. These results support our predictions that the Yauricocha mineralization in the Central Mine Area has significant depth extent," said Daniel Tellechea, the Company's President and CEO. "They also are consistent with our track record of adding mineral reserves and mineral resources annually at our three commercial mining operations.  In addition, results from the Cachi Cachi area demonstrate that mineralization also occurs laterally on the Yauricocha Fault and we plan to conduct further exploration along the Fault.  We have added significant mineral reserves at Yauricocha since our acquisition of the mine, and we expect them to be increased again when we commission another update that will have a data cutoff of January 1, 2014."

The Company has been actively drill testing the depth extension of many of the mineralized deposits at Yauricocha and during January-August has drilled more than 23,968 metres (see press releases of August 14 and 29, 2013), the results of which will be incorporated into the 2014 mineral reserve / mineral resource update.

Mineral Resource Estimate

The effective date of this resource estimate is January 1, 2013.  The mineral resource estimate was completed by Yauricocha personnel and audited by Gustavson. Thomas Matthews, MMSA QP, Senior Resource Geologist with Gustavson, is the Qualified Person responsible for this resource estimate. The resource estimation method used at Yauricocha is a traditional section and plan interpretation of mineralized zones, with grade capping by statistical analysis for each mineralized zone, and grade estimation by length-weighted mean determination. Gustavson validated the database used for resource estimation, validated the resource estimation methodology, estimated a check model with industry standard methodology to confirm the grade, tonnage, and extents of mineralization, and reviewed the mine-mill reconciliation results.  Gustavson considers the resource to meet industry standard practices, and to be CIM and NI 43-101 compliant.

For polymetallic and copper bodies, resources are presented at a cut-off which corresponds to a grade of 125 gpt expressed in terms of silver-equivalent (AgEq) at an average silver price of $24.50/oz and average metallurgical recovery for silver of 60%.  For oxide bodies, the cutoff corresponds to an AgEq grade of 240 gpt due to lower silver recoveries in oxide material.

Table 1: Measured Resources

 
Measured Resources
  Tonnes (t) AgEq(gpt) Ag(gpt) Pb(%) Cu(%) Zn(%) Au(gpt)
Cachi Cachi & Mina Central              
   Mineralization Type              
      Polymetallic 945,000 488.2 96.5 2.01 0.81 5.43 0.90
      Copper 35,000 593.9 91.7 0.51 3.51 1.35 0.89
      Oxide 249,000 857.8 407.4 9.26 0.36 1.04 1.86
Mina Ipillo (Polymetallic)   -          
Mina Victoria (Copper Ore)   -          
TOTALS 1,229,000 566.2 159.4 3.44 0.80 4.42 1.09
               

Table 2: Indicated Resources

 
Indicated Resources
  Tonnes (t) AgEq(gpt) Ag(gpt) Pb(%) Cu(%) Zn(%) Au(gpt)
Cachi Cachi & Mina Central              
   Mineralization Type              
      Polymetallic 3,916,000 376.6 66.4 1.23 1.06 3.43 0.74
      Copper 168,000 456.2 81.8 0.60 2.62 0.76 0.80
      Oxide 508,000 860.8 378.1 9.93 0.28 1.20 2.25
Mina Ipillo (Polymetallic) 169,000 603.5 140.8 1.33 1.32 6.34 1.30
Mina Victoria (Copper Ore) 149,000 434.2 95.7 0.84 2.37 1.02 0.54
TOTALS 4,910,000 439.0 102.6 2.10 1.08 3.13 0.91
               

Table 3: Measured and Indicated Resources

 
Measured and Indicated Resources
  Tonnes (t) AgEq(gpt) Ag(gpt) Pb(%) Cu(%) Zn(%) Au(gpt)
Cachi Cachi & Mina Central              
   Mineralization Type              
      Polymetallic 4,861,000 398.3 72.2 1.38 1.01 3.82 0.77
      Copper 203,000 479.9 83.5 0.58 2.77 0.86 0.82
      Oxide 757,000 859.8 387.7 9.71 0.30 1.15 2.12
Mina Ipillo (Polymetallic) 169,000 603.5 140.8 1.33 1.32 6.34 1.30
Mina Victoria (Copper Ore) 149,000 434.2 95.7 0.84 2.37 1.02 0.54
TOTALS 6,139,000 464.4 114.0 2.37 1.02 3.39 0.95
               

Table 4: Inferred Resources

 
Inferred Resources
  Tonnes (t) AgEq(gpt) Ag(gpt) Pb(%) Cu(%) Zn(%) Au(gpt)
Cachi Cachi & Mina Central              
   Mineralization Type              
      Polymetallic 181,000 382.9 71.4 1.10 0.64 4.82 0.65
      Copper - - - - - - -
      Oxide 189,550 839.1 400.4 9.02 0.22 0.15 2.21
Mina Ipillo (Polymetallic) - - - - - - -
Mina Victoria (Copper Ore) - - - - - - -
TOTALS 370,200 616.5 239.9 5.15 0.42 2.43 1.45
               

Quality and grade are estimates and are rounded to reflect the fact that the resource estimate is an approximation. Mineral resources are not mineral reserves and do not demonstrate economic viability.  There is no certainty that all or any part of the mineral resource will be converted to mineral reserves. Quantities may not sum due to rounding.

Silver Equivalency is represented as a recovery-adjusted value for silver, lead, copper, and zinc, represented as silver-equivalent grade according to the formula:

AgEq= (Ag *Pag* Rag/31.1035)+(Pb*Ppb*Rpb*22.05)+(Cu*Pcu*Rcu*22.05)+(Zn*Pzn*Rzn*22.05)
(Pag* Rag)

Where the symbols represent:

Table 5:  Silver Equivalent Calculation Values

Metal Symbol Grade
Units
Price Price
Symbol
Recovery
Symbol
Silver Ag g/t 24.50 $/tOz Pag Rag
Lead Pb % 0.93 $/lb Ppb Rpb
Copper Cu % 3.30 $/lb Pcu Rcu
Zinc Zn % 0.88  $/lb Pzn Rzn


Recovery Polymetallics Copper Oxides
Rag 59.76% 63.90% 31.98%
Rpb 80.32% 0.00% 54.20%
Rcu 69.65% 89.86% 0.00%
Rzn 88.65% 0.00% 0.00%

Metals price assumptions are based on 5-year trailing averages. (5-year trailing averages were used because it was determined that three-year trailing averages are higher than current spot prices, and might overstate the economics) Recovery assumptions are based on 2-year trailing average production recoveries for the Chumpe Mill.

Mineral Reserve Estimate

The effective date of this reserves estimate is January 1, 2013.  The mineral reserves estimate was completed by Yauricocha personnel and audited by Gustavson. Thomas Matthews, MMSA QP, Senior Resource Geologist with Gustavson Associates LLC, is the Qualified Person responsible for this resource estimate.  Gustavson Associates validated the database used for resource estimation, validated the resource estimation process, estimated a check model with industry standard methodology to confirm the grade, tonnage, and extents of mineralization, audited and updated factors and cutoffs for conversion of resources to reserves, and reviewed the mine-mill reconciliation results.  Gustavson considers the reserves to meet industry standard practices, and to be CIM and NI 43-101 compliant.

Mineral reserves are defined as that portion of mineral resources which are economically extractable, and for which there is mining access planned.  The stated reserves include factors for dilution, ore loss, and mine-mill reconciliation.  Therefore the grades are somewhat less than the resources, and the tonnages are somewhat higher.  The reserves have been used in the economic analysis directly from the mine plan. For polymetallic and copper bodies, reserves are presented at a cut-off which corresponds to a grade of 125 gpt expressed in terms of silver-equivalent (AgEq) at an average silver price of $24.50/oz and average metallurgical recovery for silver of 60%.  For oxide bodies, the cutoff corresponds to an AgEq grade of 240 gpt due to lower silver recoveries in oxide material.  This cutoff is the silver-equivalent grade at which the recoverable value of the contained metal exceeds the cost to mine and process the material.  Silver equivalency calculation is as disclosed above.

Reserve Estimate Effective Date January 1, 2013

Table 6: Yauricocha Proven Mineral Reserves

 
Proven Reserves
  Tonnes (t) AgEq(gpt) Ag(gpt) Pb(%) Cu(%) Zn(%) Au(gpt)
Cachi Cachi & Mina Central              
   Mineralization Type              
      Polymetallic 835,000 351.5 69.8 1.42 0.59 3.92 0.68
      Copper 56,000 516.6 75.8 0.31 3.08 0.84 0.65
      Oxide 257,000 616.7 294.2 6.63 0.28 0.75 1.51
Mina Ipillo (Polymetallic) - - - - - - -
Mina Victoria (Copper Ore) - - - - - - -
TOTALS 1,148,000 418.9 120.2 2.53 0.64 3.06 0.86
               

Table 7: Yauricocha Probable Mineral Reserves

 
Probable Reserves
  Tonnes (t) AgEq(gpt) Ag(gpt) Pb(%) Cu(%) Zn(%) Au(gpt)
Cachi Cachi & Mina Central              
   Mineralization Type              
      Polymetallic 3,970,000 283.3 50.1 1.08 0.70 2.70 0.59
      Copper 137,000 294.9 59.9 0.60 1.64 0.61 0.58
      Oxide 789,000 642.3 286.2 7.32 0.20 0.92 1.79
Mina Ipillo (Polymetallic) 186,000 497.8 116.6 1.13 1.07 5.25 1.17
Mina Victoria (Copper Ore) 164,000 367.1 81.0 0.76 2.00 0.92 0.49
TOTALS 5,246,000 347.8 89.2 2.00 0.71 2.41 0.79
               

Table 8: Yauricocha Proven and Probable Mineral Reserves

 
Proven and Probable Reserves
  Tonnes (t) AgEq(gpt) Ag(gpt) Pb(%) Cu(%) Zn(%) Au(gpt)
Cachi Cachi & Mina Central              
   Mineralization Type              
      Polymetallic 4,805,000 295.2 53.5 1.14 0.68 2.91 0.61
      Copper 193,000 359.4 64.5 0.52 2.06 0.68 0.60
      Oxide 1,045,000 636.0 288.1 7.15 0.22 0.88 1.72
Mina Ipillo (Polymetallic) 186,000 497.8 116.6 1.13 1.07 5.25 1.17
Mina Victoria (Copper Ore) 164,000 367.1 81.0 0.76 2.00 0.92 0.49
TOTALS 6,394,000 360.6 94.8 2.09 0.70 2.53 0.80
               

Quality and grade are estimates and are rounded to reflect the fact that the reserve estimate is an approximation. Quantities may not sum due to rounding.

Quality Control

The quality assurance-quality control (QA-QC) program employed by Sierra Metals has been described in detail in the NI 43-101 report on Yauricocha dated November 15, 2013, prepared by Gustavson Associates of Denver, which is available for review on SEDAR.

Mining and Economics

Yauricocha is an underground mine which has been in continuous operation for over 40 years.  Mining at Yauricocha is accomplished by various extraction methods, principally sublevel caving and overhand cut and fill stoping.  Ore is processed at the Chumpe mill, which operates three process streams, Polymetallic, Copper, and Oxide, to produce as many as five marketable concentrates.

All reserves will be processed at the operation's current flotation mill with resultant concentrates of copper, lead oxides, lead sulfides and zinc transported off-site under processing contracts with the operation's sole customer.  Mining is all underground, with processing and tailings storages nearby.

The Base Case for the Yauricocha operations anticipates mining the currently defined resources and reserves over 5 years and is forecast based upon the five-year trailing average of metals prices and upon the operating costs and capital costs consistent with recent operations.  4.5 million tonnes of material are projected to be mined during this time with a projected Before-Tax Net Present Value at 8% ("NPV-8") of $205 million and an After-Tax NPV-8 of $141 million.   The after-tax results are considered the base case.

There is no IRR or payback period, as the mine is in operation, therefore there is no initial capital required for start-up.

It should be noted that an additional two years of operation can be achieved with the proven and probable reserves identified.

The production decision was not based on a feasibility study of Mineral Reserves demonstrating economic viability.  There is an increased uncertainty and economic and technical risks of failure associated with this production decision. Production and economic variables may vary considerably, due to the absence of a complete and detailed site analysis according to and in compliance with NI 43-101 Standards of Disclosure specific risk analysis.

The technical content of this news release has been approved by Thomas L. Robyn, Ph.D., CPG, RPG, a Qualified Person as defined in NI 43-101.

About Sierra Metals

Sierra Metals Inc. is a Canadian mining company focused on production of precious and base metals from its Yauricocha Mine in Peru, its Bolivar Mine and Cusi Mine in Mexico. In addition, Sierra Metals is exploring several precious and base metal targets in Peru and Mexico. Projects in Peru include Adrico (gold), Victoria (copper-silver) and Ipillo (polymetallic) at the Yauricocha Property in the province of Yauyos and the San Miguelito gold properties in Northern Peru. Projects in Mexico include Bacerac (silver) in the state of Sonora, La Verde (gold) at the Batopilas Property in the state of Chihuahua, and Las Coloradas (silver) at the Melchor Ocampo Property in the state of Zacatecas.

The Company's shares trade on the Bolsa de Valores de Lima and the Toronto Stock Exchange under the symbol "SMT".

Forward-Looking Statements

Except for statements of historical fact contained herein, the information in this press release may constitute "forward-looking information" within the meaning of Canadian securities law. Other than statements of historical fact, all statements are "forward-looking statements", which involve various known and unknown risk and uncertainties and other factors, including market conditions that may affect the Company's ability to execute its current business plan.  Actual results might differ materially from results suggested in any forward-looking statements. The Company assumes no obligation to update the forward-looking statements, or to update the reasons why actual results could differ from those reflected in the forward-looking statements unless and until required by securities laws applicable to the Company. Additional information identifying risks and uncertainties is contained in filings by the Company with the Canadian securities regulators, which filings are available at www.sedar.com

 

 

 

SOURCE Sierra Metals Inc.



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