ASX / MEDIA ANNOUNCEMENT ASX: NCZ
12 September 2017
NEW CENTURY ACHIEVES A MAJOR INCREASE IN RESOURCE FOR THE CENTURY TAILINGS DEPOSIT
100% Measured Resource of 78.9Mt at 3.02% zinc, 0.47% lead and 12.4g/t silver for a total contained metal content of 2,380,000t Zn, 370,000t Pb & 31,500,000oz Ag
Entire Century Tailings Deposit in the Measured Resource category
23% increase in total zinc metal content from previous Mineral Resource
Measured Resource to be used as production basis for Restart Study, due Q4 2017
Significant lead and silver metal content to provide potential by-product credits
High-grade zones to provide potential increased production during initial operations
The mining leases at Century now hold a Global contained metal Resource of over:
2,600,000 tonnes of zinc
700,000 tonnes of lead
42,500,000 ounces of silver
Figure 1: Century Tailings Deposit looking South
New Century Resources Limited (Company or New Century) (ASX:NCZ) is pleased to announce the results of the independently estimated Mineral Resource for the Century Tailings Deposit. The upgraded Mineral Resource was estimated by Optiro Pty Ltd which had also been responsible for the previous estimate for the Deposit.
Table 1: Upgraded JORC Code 2012 compliant Mineral Resource estimate for the Century Tailings Deposit
Resource Category | Tonnes (Mt) | Zinc (%) | Lead (%) | Silver (g/t) | Metal Content |
Measured | 78.9 | 3.02 | 0.47 | 12.4 | 2,380,000t zinc 370,000t lead 31,500,000oz silver |
Figure 2: Plan view of the Century Tailings Deposit showing drilling programs
The previously reported estimate for the Century Tailings Deposit was an Indicated Resource of 12.8Mt at 2.97% zinc and an Inferred Resource of 58.2Mt at 2.68% zinc for a total 71Mt at 2.73% zinc (1,940,000t of contained zinc metal).
The upgraded estimate therefore represents:
an 11% increase in total tonnes;
an 11% increase in zinc metal grade;
a 23% increase in total contained zinc metal;
the first ever reporting of lead and silver in the Mineral Resource; and
a 100% conversion of Indicated and Inferred Resources to a Measured Resource. Commenting on the upgraded Mineral Resource, Managing Director Patrick Walta stated:
"New Century is excited to announce this significant increase in metal content for the Century
Tailings Deposit. The scale of this Measured Resource clearly provides an opportunity for substantial operations to be undertaken on site via the near term restart of the existing processing plant.
In addition, it is pleasing to see that resources at the Deposit have achieved a Measured Resource category, representing the highest confidence level possible under the JORC Code for Mineral Resource reporting. The Company is now targeting conversion of the new Resource to a Reserve as part of the Restart Study, which is due within the fourth quarter of 2017."
The Mineral Resource has been classified as Measured in accordance with the JORC Code (2012) due to the low variability and high confidence in all of the variables estimated. Furthermore, the comparison of the new Century Tailings Deposit block model grades (per year and per estimation domain) against the tailings stream grades from historical operations, representing many thousands of individual shift composite assays taken over the life of the mine, shows an overall difference of only 6%, well within the margin of error normally expected for a Measured Resource.
As shown in Figure 2, the entire Century Tailings Deposit is consistently mineralised, with a notable higher grade weighting toward the south-eastern corner of the Deposit. This is also the deepest part of the Deposit, with holes averaging ~20m depth, compared to a 13m Deposit average.
This higher grade zone provides an opportunity for increased zinc production during the initial years of operations and is planned to be targeted in the mine schedule as part of the Restart Feasibility Study currently underway by Sedgman (due to be completed in Q4 2017).
New Century is now finalising future production profiles based on the revised Mineral Resource and Sedgman's investigations into the tailings throughput available within the existing Century Processing Plant.
The Global Mineral Resource at Century now stands at over 2,600,000t zinc, 700,000t lead and 42,500,000oz silver (see Table 2).
Table 2: JORC 2012 Compliant Resources of the Century Zinc Mine
Deposit | Tonnes (Mt) | Grade | Contained Metal | ||||
Zinc (%) | Lead (%) | Silver (g/t) | Zinc (t) | Lead (t) | Silver (oz) | ||
Century Tailings Measured | 78.9 | 3.02 | 0.47 | 12.4 | 2,380,000 | 370,000 | 31,500,000 |
Silver King Inferred | 2.7 | 6.90 | 12.5 | 120 | 186,000 | 337,500 | 10,500,000 |
East Fault Block Inferred | 0.5 | 11.6 | 1.10 | 48.0 | 60,000 | 5,500 | 800,000 |
TOTAL | 82.1 | 3.20 | 0.87 | 16.2 | 2,626,000 | 713,000 | 42,800,000 |
Geology and geological interpretation
The deposit is a tailings dam with zinc, lead, and silver mineralisation deposited in sub horizontal layers as mine tailings sediment from up to five separate outflow sites.
Sampling and sub-sampling techniques
Quarter-core samples from the plastic, clay-like, tailings material were hand cut in the site laboratory at 1m intervals.
Drilling techniques
Drilling was carried out using a diamond drilling configuration utilising HQ3 diameter equipment.
Sample analysis method
Pulverized samples weighting 50-100g were sent to ALS Laboratory in Brisbane for analysis of Zn, Pb, Fe, S, SiO2, CaO, Al2O3 and Mn by XRF, Ag by four acid digest with an ICP-AES finish, and Specific Gravity by pycnometer with methanol.
Estimation methodology
Estimation was completed in Datamine Studio RM using ordinary kriging (OK) into parent blocks of 100 mE by 100 mN by 1 mRL. Sub-celling down to 10 mE by 10 mN by 0.10 mRL was employed at domain boundaries for adequate volume resolution. The entire volume of the TSF was estimated using ordinary kriging.
Criteria for classification
The estimated portion of the Century Tailings Deposit Mineral Resource, constrained within a boundary string (defining the dam walls and excluding outflow areas), has been classified as
New Century Resources Limited published this content on 11 September 2017 and is solely responsible for the information contained herein.
Distributed by Public, unedited and unaltered, on 12 September 2017 00:38:02 UTC.
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