Summary

Deposit type

• Epithermal

Summary:

Deposit Type
Based upon the styles of alteration, the nature of the veins, the alteration and vein mineralogy, and the geologic setting, gold and silver mineralization at the DeLamar project is best interpreted in the context of the volcanic-hosted, low-sulfidation type of epithermal model. This model has its origins in the De Lamar-Silver City district, where it was first developed by Lindgren (1900) based on his first-hand studies of the veins and altered wall rocks in the De Lamar and Florida Mountain mines. Various vein textures, mineralization, and alteration features, and the low contents of base metals in the district are typical of what are now classified as low-sulfidation epithermal deposits worldwide.

DeLamar Project Mineralization
Mineral resources and reserves, which are discussed, are in the Florida Mountain area and the DeLamar area.

DeLamar Area
The modern DeLamar open-pit mine area encompasses the historical De Lamar mine, where fissure-vein mineralization was mined from 1889–1913. Mineralized shoots in two sets of fissure veins, the Main De Lamar and Sommercamp veins, were mined at the 4th level (elevation 1,902 meters) from what are now the Sommercamp–Regan and North DeLamar open-pit zones.

Bonnichsen (1983) summarizes the DeLamar area vein mineralization as follows:
The main De Lamar section, at the site of the present-day North DeLamar pit…was 1,300 feet long in a northwest-southeast direction and up to about 300 feet wide, as measured on the No. 4 level (6,240 feet elevation). The section contained the Hamilton-Wilson No. 9 vein striking N. 25° W. and dipping 45°-66° W., and the 77 vein striking N. 62° W. and dipping 35° SW. These were connected by smaller veins and stringers. At lower levels the veins assumed steeper dips, 65 to 80 degrees being common. The 77 vein was the most important producer. The Sommercamp section, at the site of the present-day Sommercamp pit…was a zone about 300 feet across that contained ten interlinked veins striking N. 18° W. and dipping 65°-80° W. These ore-bearing zones plunged 20 to 30 degrees southward. In both, the southern limit of the ore was a clay zone several feet thick with a shallow dip to the south. These clay zones were known as iron dikes to the miners and were interpreted to be the low-angle De Lamar and Sommercamp faults by Piper and Laney (1926), Asher (1968), and Panze (1975). However, the excellent exposure in the present-day open-pit mines has shown that these zones really are mainly the thick basal vitrophyric section of the banded rhyolite unit (Tbr) which has been hydrothermally altered. In the underground workings, much of the rich silver ore—the “silver talc”—was extracted where the veins abutted against the base of this clay zone. With its shallow dip, this zone formed the upper as well as the southern limit to mineralization in both sections of the mine.

In addition to the fissure veins, the bulk mineable type of mineralization has been delineated in four broad, lower-grade zones, two of which overlap and are centered on the Sommercamp and main De Lamar fissure veins. Halsor et al. (1988) described this type of mineralization as follows:

Low-grade mineralization occurs in porphyritic rhyolite, where closely spaced veinlets and fracture fillings provide bulk tonnage ore. Most of the veinlets are less than 5 mm in width and have short lengths that are laterally and vertically discontinuous.... Locally, small veins can form pods or irregular zones up to 1 to 2 cm wide that persist for several centimeters before pinching down to more restricted widths. In highly silicified zones, porphyritic rhyolite is commonly permeated by anastomosing microveinlets typically less than 0.5 mm wide. Most of the minute veining displays well-defined contacts with the enclosing rock, and in some instances, veins can be seen to sharply cut phenocrysts. Still, in other zones, microveinlets are less distinct and difficult to distinguish from groundmass silicification.

Networks of high-density, quartz-free fractures are the sites for supergene mineralization. Major fractures generally trend north-northwest, but less prominent intervening and crosscutting fractures are present. Major fractures commonly have steep dips and show reversals in direction of dip vertically along faces. Fracture fillings commonly consist of thin coatings of goethite and jarosite, but occasionally can be filled with seams of sericite and kaolinite up to several centimeters wide. Above the clay zone, veining is characterized by narrow, chalcedony-lined fractures of irregular extent.

In the Sommercamp pit, the principal ore zone in porphyritic rhyolite occurred beneath the clay zone as a distinct shoot striking north-northwest, dipping 40° E; and plunging 9½° SE. It was 27 m thick at the south end and thickened to 90 m at the north end. The ore-waste boundary at the base of the shoot was sharp with ore-grade material (>2 oz Ag) in the shoot abruptly dropping to waste across a single 1.5-m sample interval. The base of the ore shoot was remarkably planar but dipped 40° E as mentioned above. The top of the ore shoot was undulatory and more or less defined by the base of the clay zone over the porphyritic rhyolite. Generally, major mineralized shoots in the Glen Silver, North DeLamar, and Sullivan Gulch zones all plunge 10° to 15° to the southeast. Determining the plunge in the North DeLamar pit proved difficult due to a very complex cross-faulting pattern.

The above description seems to have been based on the Sommercamp and North DeLamar mineralized zones. No data indicate different mineralization styles at Glen Silver and Sullivan Gulch. However, there is no indication that major fissure-vein mineralization was mined historically or encountered in exploration drilling in the Sullivan Gulch and Glen Silver zones, where to date, the relatively shallow drilling has intersected mineralization of the bulk mineable type.

Florida Mountain Area
Both fissure veins and the bulk-mineable type of mineralization are present at Florida Mountain, and both have contributed to past gold and silver production. The veins cropped out intermittently near the crest and on the flanks of Florida Mountain, in some cases with lateral continuity of 1.6 kilometers or more, even though vein widths were usually only a few meters or less. Piper and Laney (1926) reported their dips as 75° to 80° W, transitioning in their northern extents to steep east dips.

The veins in Florida Mountain were mapped in greater detail in the 1970s and 1980s by Earth Resources, NERCO, and later by Integra geologists (e.g., Figure 7-7), in part with the benefit of trenching and drilling. The most complete historical vein and geologic map that Mr. Bickel is aware of is a NERCO map from 1989. The NERCO 1989 map shows a somewhat different, more detailed picture of the vein array than Piper and Laney’s 1926 map.

In the quartz latite and rhyolite, at least some of the veins branch upward into multiple narrow veins and vein-cemented breccia—separated by intensely altered rhyolite—to form sheeted vein and breccia zones as much as 6.1 meters or more in width. These broader sheeted vein and breccia zones comprise the bulk-mineable style of mineralization at Florida Mountain, particularly where adjacent fracture networks and flow bands in the rhyolite have been permeated with narrow, discontinuous quartz and breccia veinlets. Four such zones were described by Mosser (1992) and referred to as the Tip Top, Stone Cabin, Main Trend (Black Jack), and Clark deposits. The mineralogy and paragenesis of the gold and silver mineralization are similar, if not the same, as that described for the fissure veins.

Mining Methods

• Truck & Shovel / Loader

Summary:

The Project will be a conventional truck-and-shovel open-pit operation across two primary mining areas: Florida Mountain and DeLamar, supplemented by historical stockpiles/backfills adjacent to the pits. Mining and material movement are scheduled to prioritize early cash flow by starting in Florida Mountain, with DeLamar ramping up later in the schedule. This section summarizes the mining approach, production sequencing, material handling (including stockpiles/backfill), and supporting infrastructure.

Ore will be hauled to the crushing facility and then stacked on the heap leach pads.

Development rock will be stored in development rock storage facilities (DRSFs) located near each of the Florida Mountain and DeLamar deposits and backfilled into pits where available.

Mine Production Schedule
The schedule is developed on monthly periods, with mobilization and site construction activities starting in Month –12 of Year –1. Pre-stripping at Florida Mountain commences in Month –5, or 7 months after mobilization. Heap leach processing begins in Month 1 of Year 1. Preproduction mining provides approximately 2.6 Mt of leach material, which is crushed and placed as overliner on the heap leach pad prior to stacking ramp-up. The nominal leach stacking/processing rate is 35,000 t/d (12.45 Mt/y). Year 1 stacking totals 11.9 Mt as the operation ramps to a steady state.

Heap leach throughput in any period is constrained by mining sequence, ore release, and required stripping, and therefore may vary from the nominal stacking rate during ramp-up and select pushbacks. Leaching starts with Florida Mountain material in month 1 of production. The processing of DeLamar leach material starts in year 3.8, before which Integra will install the agglomeration circuit. The DeLamar leach material will be processed at the same rate as the Florida Mountain material.

Florida Mountain and DeLamar non-oxide material is stockpiled for potential future processing in alternative flowsheets outside the FS case.

Over a period of six months, the total mining rate will ramp up from 1,000 tonnes per day to about 60,000 tonnes per day. A maximum of 72,000 tonnes per day is used from month 5 through month 8 to match the stripping requirements of Florida Mountain Phase 1.

Development rock generated during mining includes material classified as potentially acid-generating (PAG) and non-acid-generating (NAG), based on project geochemical characterization. For mine planning and scheduling, PAG and NAG are included within the development rock totals in the production schedule and material movement tables. Placement of PAG material is assumed to occur in designated development rock storage facilities and/or approved pit backfill locations consistent with the site water management, reclamation, and closure approach.

Ore stockpiles will be located in or adjacent to pits. The stockpiles will store low-grade material longer term and some higher-grade material during initial mining. Stockpile management will be required to manage processed metal grades and manage the blending of the various ore types. To optimize the mine, stockpile management will be managed with more detailed mine planning and scheduling during mine operation. The current mine plan has these ore stockpiles depleted in year 10 of production.

Earlier mining studies identified the water table at an elevation of around 1,810-meters. All the Florida Mountain mining and most of the DeLamar Pit mining is above this elevation. The mining at Sullivan Gulch phase 2 does extend about 160 meters below the 1,810-meter elevation line. RESPEC assumes that the two pit pumps will be sufficient to maintain a dry pit.

The mine is anticipated to operate 24 hours per day with four work crews working four days on and four days off and rotating between day shift and night shift. The daily shift schedule will be 12 hours per day reduced to account for standby time including startup/shutdown, lunch, breaks, and operational delays totaling 3.0 hours per day. This allows for 21 work hours each day, an 87.5% schedule efficiency.

Comminution

Crushers and Mills

Summary:

Two-Stage Crushing
The two-stage crushing circuit will use a mineral sizer in series with three roll crushers to achieve a nominal size of 80% finer than (P80) 19 mm at a rate of 35,000 tonnes per day. Mining and process operations begin at Florida Mountain, with the two-stage crushing circuit installed adjacent to the Florida Mountain pit. When mining is completed at Florida Mountain, the crushing facility will be relocated adjacent to the DeLamar HLP where a vibrating screen to screen 25.4 mm minus material for agglomeration and proper curing will be integrated, with the product from the secondary stage of crushing performed by the roll crushers. Ultimately the ore from Delamar pit that includes a higher percentage of clays will require agglomeration and therefore will be stacked on the Delamar HLP via overland conveyor, grasshoppers, and radial stacking system.

ROM ore stockpiles will be established at both the Florida Mountain and DeLamar pits to provide flexibility for crushing and leaching operations during equipment downtime and during the transition from Florida Mountain to DeLamar mining.

The mass flow rates of the mineral sizer and roll crushers are based on a crushing facility availability of 83%. This crushing facilities availability includes mechanical availability and equipment utilization.

Run-of-mine ore will be transferred by haul trucks from pit to the crushing facility. Haul trucks will direct dump into two apron plate feeders that transport material to the mineral sizer. The speed of each apron plate feeder can be adjusted to control the ore throughput rate. A discharge conveyor will transport the P80 133 mm sized material from the mineral sizer to the roll crushing system to further reduce the material size to P80 of 19 mm.

The Florida Mountain secondary crush product will be stockpiled for HLP stacking. The DeLamar ore has an intermediate agglomeration and cure stockpile for material that is 25.4 mm minus after the primary crushing stage.

Agglomeration & Cure Stockpile
Florida Mountain ore does not require agglomeration, but certain DeLamar ore types contain fines that will require agglomeration to ensure adequate heap permeability and recovery. Approximately 15% of the DeLamar ore is expected to pass through a 25.4 mm screen after primary crush. In allowance for variability in feed material, the sizing of the drum and cement silo was completed assuming 30% of the material. Fine DeLamar ore that requires agglomeration will be processed through the mineral sizer, then screened by double deck 50.8 mm screen, then onto a 25.4 mm screen. Ore passing the 25.4 mm screen will be agglomerated. Material greater than 50.8 mm and secondary screen of 25.4 mm will be classified as oversized and sent to the roll crusher for processing to achieve a P80 of 19mm.

The prepared fines will continue to the agglomeration drum sized at 3.6 m diameter by 10 m length and powered by a single 260 kW motor, with Portland cement added to agglomerate and add protective alkalinity to the ore. Raw water is added to the agglomeration drum at 69.3-76.1 m3/hr via internal spray bars. After passing through the agglomeration drum, ore will be radial stacked to the 24-hr cure pile to allow the cement to solidify around the ore nodules. After 24 hours of curing, ore will be loaded into a reclaim feeder via a CAT 988 frontend loader and onto the overland conveyor. The final agglomerated product will be recombined with the non-agglomerated and crushed 19mm ore material on the overland conveyor and conveyed for stacking on the DeLamar HLP.

Processing

• Smelting
• Crush-and-stack plant
• Electric furnace
• Heap leach
• Merrill–Crowe
• Dewatering
• Filter press
• Cyanide (reagent)

Summary:

The DeLamar project’s oxide and transitional mineralization is amenable to conventional cyanide heap leaching followed by Merrill Crowe processing to recover gold and silver. The project includes two heap leach facilities: one heap leach pad (HLP) at Florida Mountain (Florida Mountain HLP) and one at DeLamar (DeLamar HLP). The construction and operation of these facilities are phased according to the mine production schedule. Haul trucks will transfer run-of-mine ore from the pits to a two-stage crushing facility that will initially be located adjacent to the Florida Mountain pit and will then be moved to a site adjacent to the DeLamar HLP when mining at Florida Mountain stops. The crushing facility is semi-mobile and therefore a move primarily using fleet equipment will take place over a two week period. The primary difference in processing Florida Mountain and DeLamar ore is the presence of clay in the DeLamar ore. Due to this agglomeration is introduced into the process, as well as changing the stacking method from haul trucks to conveyors.

After two-stage crushing, Florida Mountain ore will be truck stacked on the Florida Mountain HLP and leached, pregnant leach solution (PLS) collected in the in-heap process pond and conveyed via doublecontained piping to the centrally located Merrill Crowe plant immediately south of the DeLamar HLP site. Residual leaching operations at the Florida Mountain HLP will continue when mining and crushing move to the DeLamar pit and stacking transitions from the Florida Mountain HLP to the DeLamar HLP.

After mining shifts to the DeLamar pit, haul trucks will move mined ore from the DeLamar pit to the twostage crushing facility adjacent to the DeLamar HLP. Material crushed to 25.4 mm minus will be screened, agglomerated, and placed in the cure stockpile. The agglomerated ore will then be recombined with the product from the secondary roll crushers and conveyor-stacked on the DeLamar HLP. The conveyor system includes an overland conveyor from the crushing and agglomeration area that feeds into a series of grasshopper conveyors and a radial stacker system for stacking on the DeLamar HLP. Pregnant leach solution will collect in the DeLamar HLP’s in-heap process pond and then pumped to the Merrill Crowe plant for recovery of gold and silver.

The product of the Merrill Crowe process is a gold and silver-bearing precipitate that will be transported to Integra’s operating Florida Canyon Mine refinery for processing into gold and silver doré.

Process Description
Heap Leach Facilities
There are two heap leach pads (HLP) one located near Florida Mountain Pit, and one near DeLamar Pit. Each HLP will be valley fill utilizing industry leading design standards meeting stability, process, and climate targets. HLP with underdrain, liner, barren solution distribution, and solution collection systems. Each heap leach pad will include an in-heap process pond, event pond, leak detection system, and pipe system to convey the PLS to a centrally located Merrill Crowe plant. Both pads will be stacked at a rate of 35,000 tonnes per day, in nominal 10 m lifts, with a side slope design of 3:1 (horizontal:vertical).

Florida Mountain Heap Leach Pad Stacking
After Florida Mountain ore is crushed and prior to being stockpiled quicklime is applied to the ore at target rates by ore type. A 993 loader will transfer crushed ore from the crushing stockpile to 785 haul trucks for stacking on the Florida Mountain HLP. A dozer will be used to further level material to prepare for installation of irrigation lines and leaching. Seven 785 haul trucks will be used for Florida Mountain HLP stacking operations and to deliver run-of-mine material to the crushing facility. Stacking operations at the Florida Mountain HLP are scheduled from year -1 to year 5.

DeLamar Heap Leach Pad Stacking
Crushed and agglomerated product for the DeLamar HLP reports to the stacking system, and quicklime application to the ore at target rate by ore type on the overland conveyor. The overland conveyors are followed by grasshopper conveyors, and ultimately a stacker conveyor. The DeLamar HLP stacking system will be comprised of three overland conveyors, 36 grasshopper conveyors, and two horizontal index feed conveyors feeding the HLP radial stacker.

Leaching Operations
The Florida Mountain and DeLamar heap leach pads will be irrigated with barren solution containing sodium cyanide to leach metals at a nominal flow rate of 1,360 m3/h (application rate of 6.11 l/s/m2). The Florida Mountain HLP has barren solution distributed to it via a 610 mm CS STD pipe encased in a 864 mm SDR 32.5 pipe for containment. The DeLamar HLP has barren solution distributed to it via a 610 mm CS STD pipe up the east side of the HLP and a 762 mm SDR 11 pipe around the south side of the HLP. The barren solution flow rate will ramp up as the surface area of the pad increases, requiring approximately 2 years to reach full leach area and the nominal operational flow rate. Barren solution will be delivered to the pads from the Merrill Crowe plant via dual-contained piping to a series of pipe headers along the perimeter of the heaps.

Merrill Crowe Plant and Refinery
To recover metals from both the DeLamar and Florida Mountain heap leach pads, one centrally located Merrill Crowe plant will process PLS. The Merrill Crowe plant’s metal-bearing filtrate product will be transported to the refinery at Integra’s operating Florida Canyon Mine for further processing.

The PLS reporting to the process ponds will be pumped to the clarifier filter feed surge tank at the Merrill Crowe plant. Four clarifying filters arranged to operate in parallel—three operating and one on standby— will clarify the solution. The filters will be precoated with diatomaceous earth (DE) to aid filtration, providing clear solution to increase zinc reactivity. Clarified solution continues to the deaeration tower to remove dissolved oxygen. A settling pond receives backwash water from the clarifier filters to settle diatomaceous shale before the solution is recycled. After deaeration, powdered zinc and cyanide will be added to the solution to initiate an exchange redox reaction where zinc metal loses electrons to gold and silver which reduces gold and silver to their metallic state and oxidizes zinc to form in solution cyano-complexes.

The mixture is then pumped to four recessed plate and frame filters in parallel—three operating and one standby. Gold and silver precipitation by the electron exchange reaction continues as the solution flows to precipitate filters that collect gold and silver in filter cakes. The filter cakes containing the gold and silver are prepared for transport to the Florida Canyon refinery. The filtrate solutions, stripped of metals, report to the barren solution tank. Sodium cyanide is added and the solution is recycled to the heaps for continued leaching.

The precipitates (filter cakes) are shipped ~362 km to Integra’s active Florida Canyon Mine, where the precipitates are dried in a retort furnace to remove moisture and mercury, then processed through fluxing and smelting in an induction furnace. The molten metal is poured into bullion molds to produce doré bars, which are sold and shipped to the customer.

Off gases from the induction furnace are filtered and passed through a bed of sulfur-impregnated carbon to remove trace mercury and acidic gases. Slag produced by the induction furnace is poured into a slag pot, weighed, sampled, and stored for further processing.

Water Supply

Summary:

Water Management
The DeLamar project’s water management strategy will keep different waters separate through diversions, conveyance systems, and water storage facilities. Separation is based on predicted water quality. The different “types” of water include, contact water, process water, non-contact water, and haul road runoff. “Contact water” is surface water runoff that comes in contact with mining areas and DRSFs and it includes pit wall runoff and DRSF underdrain seepage. “Process water” is solution containing reagents used to extract metal from ore, and it includes any water that comes into contact with process water such as meteoric water that has contacted in-use process water because it fell on the HLPs. During mine operations and active heap leaching, process water will be recycled and will stay in the process circuit unless it is lost by evaporation or entrainment within the HLPs. “Non-contact water” is water that has not come into contact with mining or mineral processing areas, process water, or DRSFs. It includes surface stormwater runoff from undisturbed areas that is diverted or collected to prevent it from touching contact water or process water. “Haul road runoff” is meteoric water or water used in dust suppression that runs off of haul roads that do not have any ROM material and do not receive drainage from mining or ore processing areas.

Contact Water Management
All site contact water will be diverted, captured in lined collection ponds, and pumped to the two water management ponds through closed-conduit piping systems for use in heap leach and process operations. Contact water collection ponds will be constructed for the two DRSFs, two ROM stockpiles, and the crushing facility. In the pits, contact water will collect in sumps that will be relocated as mining progresses. Historical contact water sources that are currently pumped directly to the water treatment plant will be integrated into the project’s water management system by pumping their waters into the adjacent water management ponds, where they will combine with the current operation’s contact water.

Non-Contact Water Management
Where needed, Integra will build berms and ditches to manage and divert as much non-contact stormwater as possible away from mine facilities and into natural stream channels.

Water Supply
The DeLamar Mining Company and Integra hold five decreed water rights and three water right permits authorizing mining uses. The Idaho Department of Water Resources (IDWR) is currently licensing (perfecting) the three permits. While groundwater rights are available, hydrogeologic studies have not identified a productive groundwater source. Thus, groundwater rights are excluded as a water supply source for the project. The water right associated with historical Adit 16 is nonconsumptive and is also excluded as a water source.

These are junior water rights that are expected to be curtailed during the irrigation season because senior water rights with priority dates in the 1870s and 1880s take priority from Jordan Creek. The timing of curtailment will vary from year to year based on runoff and may not occur if curtailment of DeLamar water rights would have no measurable benefit to downstream senior-priority irrigation water rights (HDR 2023).

During times of curtailment or insufficient flows in Jordan Creek, water will be supplied via the contact water system. The total existing and designed pond capacity that will be available to store contact water to supply heap leach, crushing, dust suppression, and other ancillary uses is ~2 million m3. Prior to use, contact water required for heap leach and process operations will require treatment through the first stage of the HDS process.

The site water balance model indicates that the combination of Integra’s surface water rights and collected contact water will meet operational requirements. To confirm the sufficiency of water supply and pond storage, the water balance was also used to evaluate consecutive historical low precipitation years. The evaluation showed that the water supply would be sufficient in that scenario. However, the water management required to maintain supply in this scenario will be difficult to execute. The project’s water supply can be supplemented through the purchase of additional water rights with a priority date that would grant the project seniority access to water from Jordan Creek. To mitigate this risk, Integra is actively pursuing the purchase of additional water rights.

Process Plant Water Consumption
A site wide water balance has been developed (in GoldSim 14.0) as part of the company’s permitting efforts to evaluate the water demand of heap leach operations. The water demand expected for HLP operations averages approximately 50 m3/hr during operations, with seasonal variations based on snowfall and precipitation records (Forte 2025c). Dust suppression demands are estimated to range from 0 m3/hr to 69 m3/hr during operations and will also vary with seasonality with an average consumption of approximately 29 m3/hr during operations. Based on catchment basins defined by the proposed pits and DRSFs and a combined proposed pond storage capacity of approximately 2.1 million m3 (excluding the closed-circuit heap leach and process facilities), the DeLamar project is projected to have adequate water supply through existing surface water rights from Jordan Creek and management of the contact water system during spring runoff.

Commodity Production

Operational metrics

Personnel

Job Title	Name	Profile	Ref. Date
Chief Operating Officer	Cliff Lafleur		Feb 18, 2026
Consultant - Mining & Costs	Keith Watson		Dec 8, 2025
Consultant - Recovery Methods & Costs	Deepak Malhotra		Dec 8, 2025
Director Technical Services	James Frost		Feb 18, 2026
President and CEO	George Salamis		Feb 18, 2026
Site Operations Manager	Matthew Mock		Feb 18, 2026
VP, Corporate Development	Jason Banducci		Feb 18, 2026
VP, Engineering	Scott Olsen		Feb 18, 2026