Press Release Highlights:
- Historical records of past testwork, and a 21-year long
recent history of gold-silver production at the DeLamar Project,
are indicative of the potential for mineralization to be amenable
to both heap leaching and conventional milling
- Conventional milling at DeLamar from 1977 to 1998
produced mill recoveries averaging 96.2% gold and 79.5% silver with
limited recovery variation between oxide, transitional and
unoxidized material
- Heap leaching potential to be tested further: past
column leach testwork was conducted on mineralized material from
both DeLamar and Florida Mountain Deposits (including oxide,
transitional and unoxidized material), showing recoveries of up to
84% gold and 64% silver
- Current metallurgical testwork program is expected to
provide key data in support of a Preliminary Economic Assessment to
be conducted in H1 2019
VANCOUVER, B.C., Sept. 06, 2018 (GLOBE NEWSWIRE) --
Integra Resources Corp.
(TSXV:ITR) (OTCQX:IRRZF) (the “Company” or “Integra”) is
pleased to announce that it has commenced a comprehensive
metallurgical sampling and testwork program on the DeLamar Gold and
Silver Project (“DeLamar”, or the “Project”), located in the
historic Owyhee County mining district in southwestern Idaho. The
metallurgical sampling and testwork program will be conducted by
McClelland Laboratories, Inc. in Reno, Nevada, under the
supervision of Jack McPartland, Metallurgist/Vice President
Operations at McClelland Laboratories, Inc.
“The DeLamar Gold-Silver Project has a long history of mining
and processing, producing high-grade and low-grade gold and silver
during various periods from the late 1800s and late 1900s. An
abundance of metallurgical records recovered on-site clearly
demonstrate that the metallurgy of DeLamar is not particularly
complex, and that historical gold-silver test recoveries using
industry standard leaching techniques were excellent,” stated
George Salamis, President and CEO of Integra Resources. “Our
mission with this initial round of testwork is to follow-up on past
conventional milling and heap leach testwork, and to qualify the
extent to which heap leaching can potentially be used as an
economically viable means of gold-silver extraction on the Project.
Given the large amount of heap leach testwork conducted on the
Project by previous operators, with recoveries of up to 84% gold
and 64% silver in laboratory column leach tests, we are confident
that the results should demonstrate that heap leaching is a
potentially viable option for the project.”
“The Project hosts an extensive near surface resource that has
the potential for bulk mining. In addition, previous mine operators
of the DeLamar and Florida Mountain Deposits left behind
significant oxidized, transitional and unoxidized gold-silver
resources at surface. Metallurgical testwork on this resource will
further de-risk the project and provide processing options for the
Company as it continues to grow the existing resource and delineate
new targets and deposits around the DeLamar area,” noted George
Salamis, President and CEO.
HISTORY OF GOLD-SILVER MILLING AND METALLURGY AT THE
DELAMAR PROJECT1
Recent Historical Gold and Silver Operational Processing
and Recoveries
Records from recent historical gold (“Au”) and silver (“Ag”)
processing at DeLamar, as defined by the mineral processing that
took place on site from 1977 until 1998, hosts much of the most
relevant metallurgical data available to Integra at this time.
Processing was performed by crushing, grinding, and tank
leaching with cyanide, followed by precipitation with zinc dust and
in-house smelting of the precipitate to produce silver-gold doré.
Records show that from 1977 through 1992, the mill processed 11.686
million tonnes of mineralized material with average head grades of
1.17 g Au/tonne and 87.1 g Ag/tonne. During this 15-year period,
the DeLamar mill recovered, on average, 96.2% of the contained gold
and 79.5% of the contained silver. The historical mill feed during
this period included oxidized, partly oxidized, and unoxidized
materials.
Historical Column Leach Test Work Designed to Evaluate
Potential Heap Leaching Options
In the 1980s, the NERCO Mineral Company (“NERCO”) conducted
numerous column leach tests using mineralized material from the
Florida Mountain Deposit (“Florida Mountain”). The results of this
testwork, summarized below in Table 1, demonstrate the potential
for heap leach processing of mineralized material at Florida
Mountain, and may indicate the amenability of heap leaching on
mineralized material from DeLamar as well, based on the
similar host-rock types and styles of mineralization for both
Deposits. Clarification surrounding the different metallurgical
characteristics of Florida Mountain mineralized material versus
DeLamar mineralized material is one focus of the current
testwork.
Table 1. Compiled NERCO Florida Mountain
Column Leach Test Results
(From Statter, 1989, and Hampton, 1988, compiled by Integra,
2017)
Florida Mountain Area |
Crush Size |
Calculated Head Grade |
Duration |
Metal Extraction |
Inches |
Ag g/t |
Au g/t |
Days |
Ag % |
Au % |
Sullivan2 |
-1 |
8.50 |
0.58 |
60 |
41.9 |
82.3 |
Sullivan2 |
-1/2 |
7.78 |
0.62 |
60 |
53.8 |
82.0 |
Stone Cabin LG |
-1 |
7.71 |
0.31 |
60 |
45.2 |
85.1 |
Stone Cabin LG |
-1/2 |
10.87 |
0.34 |
60 |
43.1 |
84.5 |
Stone Cabin HG |
-1 |
15.60 |
1.61 |
60 |
39.3 |
78.1 |
Stone Cabin HG |
-1/2 |
14.40 |
1.47 |
60 |
47.6 |
84.3 |
Clark LG |
-1 |
4.94 |
0.24 |
60 |
37.5 |
52.0 |
Clark LG |
-1/2 |
4.35 |
0.24 |
60 |
53.6 |
83.7 |
Clark HG |
-1 |
14.16 |
0.86 |
60 |
36.4 |
38.7 |
Clark HG |
-1/2 |
15.29 |
0.79 |
60 |
48.9 |
59.3 |
Stone Cabin Dump |
1 |
60.38 |
3.70 |
60 |
39.7* |
83.1* |
Stone Cabin Dump |
-1 |
17.62 |
0.65 |
60 |
31.5* |
92.2* |
Stone Cabin Core |
-1/2 |
15.98 |
0.62 |
60 |
42.9* |
92.6* |
Stone Cabin Core |
-1/2 |
18.17 |
12.00 |
60 |
36.2* |
78.0* |
Tip Top Trench |
-2 |
17.35 |
1.03 |
56 |
41.6* |
92.2* |
Tip Top Trench |
-1 |
19.75 |
1.10 |
56 |
42.8* |
91.5* |
Tip Top Trench |
70% -1/4 |
21.81 |
1.03 |
56 |
45.0* |
95.0* |
- *denotes an internal DeLamar mine assay factor was applied to
silver and gold analyses
- Sullivan Core refers to drill core from the Sullivan claim in
the Florida Mountain Deposit, not the Sullivan Gulch area of the
DeLamar Deposit
- Integra is unaware of the column diameter(s) or the oxidation
state(s) of the material tested
Statter (1989) reported a pilot column leach test was performed
in 1988 using 14,850 pounds of Stone Cabin “run of dump” material.
The test was likely conducted at the DeLamar mine laboratory.
Leaching was conducted for 63 days resulting in 15.8% silver
recovery and 72.2% gold recovery.
In 1987, NERCO initiated construction of a small scale, trial
cyanide heap leach pad which was in operation for the last quarter
of 1987 until the final quarter of 1990. The trial leach pad
used low-grade run-of-mine material that was driven onto the pad by
haul truck then ripped by bulldozer to provide permeability. The
material size was reported to be approximately 70% at >20
centimeters (>8 inch). The trial pad and stacked material became
physically unstable and began to slide downhill towards the
tailings facility in 1990. In early 1991, the entire heap was
removed and placed into the tailings facility. The trial leach pad
was shut down due to physical instability, not due to the lower
leach results being obtained during the trial. The Company has
surmised that that the stacked material may not have reached the
optimum duration under leach, and therefore the overall calculated
recovery of only 41% gold and 8% silver may be understated by an
unknown quantity.
- NI 43-101 Technical Report and Estimated Gold – Silver
Resources, DeLamar Project, Integra Resources Corp. Effective Date
March 8, 2018.
2018 Metallurgical Testwork Program on DeLamar and
Florida Mountain
The current metallurgical testwork program will address three
main objectives, in support of a planned 2019 PEA:
- To establish the milling characteristics of mineralization from
the DeLamar and Florida Mountain Deposits;
- To establish the amenability of different mineralization types
from both Deposits to potential heap leaching; and,
- To provide the Company with information to establish future
“trade-off” parameters of using one or both of the above means of
gold-silver extraction on the project.
The program, to be conducted over the next several months at
McClelland Laboratories, Inc. in Reno, Nevada, under the super
vision of Jack McPartland, Metallurgist/Vice President of
Operations at McClelland Laboratories, Inc., will focus on the
following:
- Ore Variability (Bottle Roll) Composite Testing
- Column Test Composite Testing
- Load/Permeability Testing
- Scoping Mill Testing, including Bond Ball Mill Work Index
tests, cyanidation tests, flotation tests and gravity concentration
tests
Sample media used in this metallurgical study has been collected
from diamond core drill holes completed over the course of the 2018
drill program at DeLamar and Florida Mountain. Results from the
metallurgical sampling program are expected in Q4 2018 and Q1
2019.
DeLamar Exploration Ongoing
Currently two drill rigs are in operation at the
DeLamar Project, with 60 drill holes completed over 18,500 m. Many
drill assays remain outstanding and are expected to be available
for reporting upon in the coming weeks and months.
Qualified Person
The scientific and technical information
contained in this news release has been reviewed and approved by E.
Max Baker PhD. (FAusIMM), Integra’s Vice President Exploration, of
Reno, Nevada, and is a "qualified person"(“QP”) as defined in
National Instrument 43- 101 – Standards of Disclosure for Mineral
Projects.
About Integra Resources
Integra Resources Corp. is a development-stage
company engaged in the acquisition, exploration and development of
mineral properties in the Americas. The primary focus of the
Company is advancement of it’s DeLamar Project, consisting of the
neighbouring DeLamar and Florida Mountain Gold and Silver Deposits
in the heart of the historic Owyhee County mining district in south
western Idaho. The first exploration program in over 25 years is
currently underway on the DeLamar Project with more than 20,000
meters planned for 2018. The management team comprises the former
executive team from Integra Gold Corp.
ON BEHALF OF THE BOARD OF DIRECTORS
George Salamis
President, CEO, and Director
CONTACT INFORMATION
Corporate Inquiries: Chris Gordon,
chris@integraresources.com
Company website: www.integraresources.com
Office phone: 1 (604) 416-0576
This news release contains "forward-looking
information" and "forward-looking statements" (collectively,
"forward-looking statements") within the meaning of the applicable
Canadian securities legislation. All statements, other than
statements of historical fact, are forward-looking statements and
are based on expectations, estimates and projections as at the date
of this news release. Any statement that involves discussions with
respect to predictions, expectations, beliefs, plans, projections,
objectives, assumptions, future events or performance (often but
not always using phrases such as "expects", or "does not expect",
"is expected", "anticipates" or "does not anticipate", "plans",
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"intends" or variations of such words and phrases or stating that
certain actions, events or results "may" or "could", "would",
"might" or "will" be taken to occur or be achieved) are not
statements of historical fact and may be forward-looking
statements. In this news release, forward-looking statements
relate, among other things, to: statements about the estimation of
mineral resources; magnitude or quality of mineral deposits;
anticipated advancement of mineral properties or programs; future
operations; future exploration prospects; the completion and timing
of mineral resource estimates; the length of the current market
cycle and requirements for an issuer to survive in the current
market cycle; future growth potential of Integra; and future
development plans.
These forward-looking statements are based on
reasonable assumptions and estimates of management of Integra at
the time such statements were made. Actual future results may
differ materially as forward-looking statements involve known and
unknown risks, uncertainties and other factors which may cause the
actual results, performance or achievements of Integra to
materially differ from any future results, performance or
achievements expressed or implied by such forward-looking
statements. Such factors, among other things, include: possible
variations in mineralization, grade or recovery rates; actual
results of current exploration activities; actual results of
reclamation activities; conclusions of future economic evaluations;
business integration risks; fluctuations in general macroeconomic
conditions; fluctuations in securities markets; fluctuations in
spot and forward prices of gold, silver, base metals or certain
other commodities; fluctuations in currency markets (such as the
Canadian dollar to United States dollar exchange rate); change in
national and local government, legislation, taxation, controls,
regulations and political or economic developments; risks and
hazards associated with the business of mineral exploration,
development and mining (including environmental hazards, industrial
accidents, unusual or unexpected formations pressures, cave-ins and
flooding); inability to obtain adequate insurance to cover risks
and hazards; the presence of laws and regulations that may impose
restrictions on mining; employee relations; relationships with and
claims by local communities and indigenous populations;
availability of increasing costs associated with mining inputs and
labour; the speculative nature of mineral exploration and
development (including the risks of obtaining necessary licenses,
permits and approvals from government authorities); and title to
properties. Although the forward-looking statements contained in
this news release are based upon what management of Integra
believes, or believed at the time, to be reasonable assumptions,
Integra cannot assure its shareholders that actual results will be
consistent with such forward-looking statements, as there may be
other factors that cause results not to be as anticipated,
estimated or intended.
Readers should not place undue reliance on the
forward-looking statements and information contained in this news
release. Except as required by law, Integra assumes no obligation
to update the forward-looking statements of beliefs, opinions,
projections, or other factors, should they change, except as
required by law.