Sandfire Resources America Inc. (“Sandfire America” or the
“Company”, Trading symbols- TSX.V:SFR and OTCQB:SRAFF) is
pleased to provide the following announcement related to an updated
Mineral Resource estimate for the Black Butte Copper Project, a
proposed underground mine located in Montana, USA.
CEO and VP of Project Development Rob Scargill
stated: “The updated Mineral Resource estimate, supported by
substantial new drill data and geometallurgical investigation,
allows project evaluation to proceed using data in which we have an
increased level of confidence that will underpin upcoming studies
on the Black Butte Copper Project.”
The updated Mineral Resource statement for the
Johnny Lee Deposit is summarized in Table 1. This Mineral Resource
statement is based upon the Preliminary Economic Assessment
(effective date: July 12, 2013) further supported by additional
drilling, analyses, geological modeling, and extensive
metallurgical studies to provide updated recoveries.
Table 1: Mineral Resource Estimate for the Johnny Lee
Deposit as of October 15, 2019.
Category |
Quantity(Mt) |
Cu (%) |
TotalMetal (kt) |
UCZ |
Measured |
1.4 |
2.6 |
36.2 |
Indicated |
8.3 |
2.3 |
191.3 |
Measured and Indicated |
9.7 |
2.4 |
227.5 |
Inferred |
2.2 |
2.2 |
49.5 |
LCZ |
Measured |
0.6 |
5.7 |
32.9 |
Indicated |
0.6 |
7.9 |
50.5 |
Measured and Indicated |
1.2 |
6.8 |
83.4 |
Inferred |
0.5 |
6.3 |
30.3 |
Combined UCZ + LCZ |
Measured |
2.0 |
3.5 |
69.1 |
Indicated |
8.9 |
2.7 |
241.8 |
Measured and Indicated |
10.9 |
2.9 |
310.9 |
Inferred |
2.7 |
3.0 |
79.7 |
Source: SRK, 2019
- The effective date for this Mineral Resource is October 15,
2019. All significant figures are rounded to reflect the relative
accuracy of the estimates. Copper assay values were capped where
appropriate;
- Mineral Resources are not Mineral Reserves and do not have
demonstrated economic viability. Inferred Mineral Resources have a
high degree of uncertainty as to their economic and technical
feasibility. It cannot be assumed that all or any part of an
Inferred Mineral Resources can be upgraded to Measured or Indicated
Mineral Resources;
- Metallurgical recovery of copper has been estimated on a block
basis in the UCZ, averaging 77.4%, with a consistent 94.0% Cu
recovery applied to the LCZ;
- To demonstrate reasonable prospects for eventual economic
extraction of Mineral Resources, a cut-off grade of 1.00% copper
based on metal recoverability assumptions, long-term copper price
assumptions of $3.20/lb, mining costs, processing costs, G&A
costs totaling $71/t;
- There are no known legal, political, environmental, or other
risks that could materially affect the potential development of the
Mineral Resources other than those outlined in the Management
Discussion and Analyses of the June 2019 Company Quarterly Report.
All Mineral Resources are located within land currently under
control or lease to Sandfire Resources America Inc.
The 2019 Mineral Resource update was supervised
and reviewed by SRK Consulting (U.S.), Inc. (SRK) and represents
the following notable changes in the defined Mineral Resource from
the previously defined Mineral Resource estimate contained within
the Updated Technical Report and Preliminary Economic Assessment
for the Black Butte Copper Project, Montana (effective date: July
12, 2013) due to the following key factors:
- Additional drilling, analytical
data, geological and structural modeling, and interpretation of
geological and mineralization for improved confidence;
- Extensive metallurgical and
geometallurgical studies have allowed for estimates of copper
recovery that have a higher level of confidence than previously
assumed;
- Removal of Co, Ag, and Au
by-products as recent metallurgical test work has indicated that
froth flotation does not produce a copper concentrate with cobalt,
silver, or gold in payable concentrations; and
- Updated cut-off grade used to
define the Mineral Resource using recent metallurgical recovery
assumptions for copper and updated price assumptions.
Introduction
Sandfire Resources America Inc. (the Company) is
pleased to announce that an updated Mineral Resource estimate has
been completed using significant additional drill data for the
Johnny Lee Deposit, Black Butte Copper Project, Montana, USA. The
updated Mineral Resource has been prepared following the Canadian
Institute of Mining, Metallurgy, and Petroleum (CIM)
guidelines.
The Mineral Resource estimate incorporates drill
data from 140 diamond drillholes completed by its predecessors and,
48 diamond drillholes completed by the Company. The Mineral
Resource estimate has been reviewed and approved by SRK of Denver,
Colorado, USA under the supervision of Erik Ronald, an Independent
Qualified Person under NI 43-101.
Twenty-two metallurgical composite samples,
constructed from fourteen drillholes completed by the Company, were
used to conduct an extensive metallurgical test work program for
the Johnny Lee deposit. The metallurgical test results have been
integrated with systematic mineralogy of drillhole samples to
develop a metallurgical copper recovery model for the Johnny Lee
deposit. Metallurgical testing was conducted at Base Metallurgical
Laboratories (Kamloops, British Columbia) under the supervision of
Dr. Deepak Malhotra of Resource Development Incorporated, an
Independent Qualified Person under NI 43-101.
The Mineral Resource was prepared in accordance
with CIM Definition Standards and will be supported by a NI 43-101
Technical Report to be published and filed on the Company’s website
and SEDAR profile within 45 days.
Johnny Lee Deposit
The Johnny Lee copper deposit is formed by two
zones of mineralization: An Upper Copper Zone (“UCZ”) situated at
depths of 40 m – 210 m below surface and an underlying Lower Copper
Zone (“LCZ”) at depths of 340 m - 520 m below surface. A Mine
Operating Plan (“MOP”) Application for the extraction of
mineralized rock from both Zones of the Johnny Lee deposit was
submitted to the Montana Department of Environmental Quality (“MT
DEQ”) in December 2015 and following revisions was deemed complete
and compliant. A draft MOP permit was issued by the Hard Rock
Mining Bureau MT DEQ on September 18, 2017 and the Environmental
Impact Statement process started soon thereafter. The MOP proposes
underground mining of the Johnny Lee Deposit using a drift and fill
mining method and production of a copper concentrate by milling and
froth flotation. Mill tailings will be used for underground
paste-fill support and the surplus deposited in a double lined
cemented tailings storage facility.
Resource Estimation Methodology and
Parameters
An extensive quality assurance and quality
control (QA/QC) program was implemented in order to support the
Mineral Resource estimate. Diamond drill core sampling intervals
were continuously collected from above the mineralization zones to
the end of each drillhole. HQ (2.5 inch) diamond core was sawn into
half-core samples for copper analyses. Diamond drill core analyses
for copper mineralization was performed at ALS Laboratories (ALS)
in Reno, Nevada and metallurgical testing at Base Metallurgical
Laboratories in Kamloops, British Columbia, Canada. Approximately
20% of the submitted samples consisted of QA/QC samples including:
duplicates, blanks, and certified Reference Materials (CRM). All
QA/QC, sampling, drilling, and analytical methodologies have been
deemed acceptable by the QP for use in determination of Mineral
Resources as per CIM guidelines.
Geological continuity of up to eight, vertically
stacked, shallow dipping >1.2% copper mineralized layers in the
UCZ has been demonstrated and modeled as wireframe domains in
three-dimensions (3D). The >1.2% copper domains in the UCZ are
encapsulated within a zone of >0.25% copper mineralization
modeled in 3D as wireframe volumes.
Copper mineralization within the LCZ occurs
within three discrete >2.0% copper lenses that occur at
approximately the same elevation. Each of these lenses has been
modeled in 3D as separate wireframe volumes. Compositing and
capping were utilized for copper grade estimated into each modeled
domain using Ordinary Kriging for both the UCZ and LCZ. Density was
estimated into the block model by domain using Ordinary Kriging of
composited data. The block models were used to constrain the
tonnage and copper grade estimations for the Mineral Resource
estimate.
Copper Recovery Estimation
Metallurgical test work using UCZ composites has
shown that copper recoveries, using the optimized recovery process,
are highly variable. Mineralogical investigation of UCZ
metallurgical composites has demonstrated that this variability is
due to differences in copper sulfide liberation characteristics.
The estimated copper recoveries determined from copper sulfide
liberation metrics have been interpolated into a block model using
an inverse distance weighting squared process. Estimated copper
recoveries for the UCZ range from 68.2% to 87.9%.
Historic and recent metallurgical test work for
the LCZ has demonstrated relatively high recoveries with low
variability. Accordingly, a 94.0% copper recovery has been applied
to the LCZ model.
Determination of Cut-off Grade for
Resource
To demonstrate the prospect of eventual economic
extraction of Mineral Resources, SRK applied a cut-off grade that
accounts for metallurgical recovery of copper, operational costs,
and market-driven copper pricing. The following technical and
economic parameters are assumed and accounted for in the
determination of cut-off grade:
- Metallurgical recoveries: Estimated
variable copper recovery for the UCZ. Assigned mean 94% copper
recovery for the LCZ.
- Operational Costs: US$71/tonne.
This includes mining, processing and general and administrative
costs.
- Copper Price: A long term copper
price of US$3.20 per pound (US$7,055 per metric tonne) is based on
market consensus forecast for upside copper pricing.
Using these metrics, a cut-off grade of 1.0% Cu
based on recovery assumptions was used for the entire Johnny Lee
deposit.
Qualified Persons
The technical information contained in this
announcement related to the Johnny Lee Deposit has been reviewed
and approved by Erik Ronald, M. Eng., P.Geo, RM-SME, Principal
Consultant, SRK Consulting (U.S.) Inc. and Deepak Malhotra Ph.D.
RM-SME, Resource Development Inc. Messrs. Ronald and Malhotra are
Qualified Persons pursuant to NI 43-101 for Mineral Resources and
Metallurgical processing respectively. Messrs. Ronald and Malhotra
are independent of the Company. For detailed information on the key
assumptions, parameters and methods used to estimate the mineral
resources, along with other information about the Johnny Lee
Deposit, please refer to the Technical Report to be filed.
Contact Information: Sandfire Resources America
Inc. Nancy Schlepp, VP of Communications Mobile: 406-224-8180
Office: 406-547-3466 Email: nschlepp@sandfireamerica.com
Additional information on Sandfire Resources America, Inc. can
be viewed on SEDAR under the Company’s profile at www.sedar.com or
on Sandfire Resources America, Inc.’s website at
www.sandfireamerica.com
Cautionary Note Regarding Forward-Looking Statements: Certain
disclosures in this document constitute “forward looking
information” within the meaning of Canadian securities legislation,
including statements regarding the mineral resource estimates the
completion of the proposed feasibility study, permitting and the
Company’s plans for advancing the Black Butte Copper Project and
expected outcomes. Forward-looking statements include
statements that are predictive in nature, are reliant on future
events or conditions, or include words such as "expects",
"potential", "anticipates", "plans", "believes", "considers",
"significant", "intends", "targets", "estimates", "seeks",
attempts", "assumes", and other similar expressions. In making
these forward-looking statements, the Company has applied certain
factors and assumptions that the Company believes are reasonable,
including and in addition to those assumptions previously set out
in this news release that the Company will receive required
regulatory approvals, the Company’s successful advancement of
the Black Butte Copper Project toward feasibility, the expected
positive results from the Black Butte Copper Project based on the
estimates and findings contained in the Preliminary Economic
Assessment from July 12, 2013, that the Company will continue to be
able to access sufficient funding to execute its plans, that the
Company is able to procure equipment and supplies in
sufficient quantities and on a timely basis, that the
Company’s exploration and development activities on the Black Butte
Copper Project will not be affected by actions of environmental
activists or other special interest groups, and that the results of
exploration and development activities will be consistent with
management’s expectations that capital costs and sustaining costs
will be as estimated, that the assumptions underlying mineral
resource estimates are valid, and that no unforeseen accident,
fire, ground instability, flooding, labor disruption, equipment
failure, metallurgical, environmental or other events that
could delay or increase the cost of development will occur, that
the current price and demand for copper and other metals will
be sustained or will improve; that general business and economic
conditions will not change in a materially adverse manner; and the
continuity of economic and political conditions and operations of
the Company. However, the forward-looking statements in this
document are subject to numerous risks, uncertainties and other
factors, including factors relating to the Company’s operation as a
mineral exploration and development company and the Black Butte
Copper Project, that may cause future results to differ materially
from those expressed or implied in such forward-looking statements,
including that results of exploration and development activities
will not be consistent with management’s expectations,
uncertainties involved in the interpretation of drilling
results and geological tests; delays in obtaining or inability to
obtain required government or other regulatory approvals or
financing, failure of plant, equipment or processes to operate as
anticipated, the risk of accidents, labor disputes, inclement or
hazardous weather conditions, unusual or unexpected geological
conditions, ground control problems, earthquakes, flooding;
interference with the Company’s exploration or development
activities by environmental activists or other special interest
groups; inability to procure equipment and supplies in sufficient
quantities and on a timely basis; and all of the other risks
generally associated with the development of mining facilities.
There can be no assurance that such statements will prove to be
accurate, and actual results and future events could differ
materially from those anticipated in such statements. Readers are
cautioned not to place undue reliance on forward-looking
statements. The Company does not intend, and expressly disclaims
any intention or obligation to, update or revise any
forward-looking statements whether as a result of new information,
future events or otherwise, except as required by law.
Neither the TSX Venture Exchange nor its Regulation Services
Provider (as that term is defined in the policies of the TSX
Venture Exchange) accepts responsibility for the adequacy or
accuracy of this release.
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