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Colosseum Gold Project
Bankable Feasibility Study

San Bernardino County, California  ·  2Mtpa Open Pit CIL  ·  10.4-Year Mine Life

Effective Date: 11 May 2026
Prepared by: GR Engineering Services

Brownfields restart with proven metallurgy, world-class IRR, and substantial NPV upside above base gold price.

Pre-Tax NPV (5%)
$785M
Base case @ $4,200/oz gold
↑ $999M at spot $4,700/oz
Pre-Tax IRR
49.5%
Base case @ $4,200/oz gold
↑ 59.5% at spot price
After-Tax NPV (5%)
$551M
Post US federal + CA state tax
↑ $704M at spot price
Payback Period
3.6 yrs
After-tax, from first production
→ First gold target Q4 2027
Analyst summary — The Colosseum BFS is a technically straightforward open-pit restart generating exceptional margins — over $2,500/oz at today's gold price. With FEED underway, earthworks started, and a second-hand SAG/Ball mill already secured, execution risk is materially lower than a greenfields project. The primary outstanding binary is closing a ~US$186M financing gap. Management describes discussions as "advanced with globally recognised financiers."
Total Gold Production
573 koz
Over 10.4-year mine life
Avg Annual Output
75 koz/yr
First 6 years — mining phase
Peak Annual Output
102 koz
Year 6 — highest production year
AISC (Life of Mine)
$1,825/oz
$1,655/oz in active mining years
Pre-production Capex
$249M
+ US$25M contingency
Cash on Hand (DTR)
A$88M
~US$57M as at May 2026
Financing Gap
~US$186M
Target: project finance
Operating Margin
>$2,500/oz
At $4,200/oz base gold price

Project description

LocationSan Bernardino County, California
Ownership100% Dateline Resources
Mining methodOpen pit — conventional drill & blast
Processing2Mtpa Carbon-in-Leach (CIL)
Gold recovery91% LOM avg — confirmed by 1988–93 ops
Strip ratio3.0:1 — low for open-pit gold
Tailings managementDry-stack filter press — no wet dam
Workforce baseLas Vegas NV (88km) — drive-in/out daily
Proximity10km north of Mountain Pass REE mine

Scoping study vs BFS comparison

Gold price (base)$2,900 → $4,200/oz (+45%)
Mine life8.3 → 10.4 years (+25%)
Pre-tax NPV$550M → $785M (+43%)
Pre-tax IRR61% → 49.5% (higher gold base drives NPV up)
Total ore mined16.6Mt → 20.6Mt (+24%)
Strip ratio3.4:1 → 3.0:1 (improved)
C1 cash cost$1,182 → $1,651/oz (+cost inflation)
AISC$1,490 → $1,825/oz
Pre-production capex$138M → $249M (2Mtpa scale-up)

Base case vs spot price

Gold price$4,200/oz  →  $4,700/oz
Undiscounted pre-tax cashflow$1,082M → $1,357M
Undiscounted post-tax cashflow$779M → $978M
Pre-tax NPV5%$785M → $999M
After-tax NPV5%$551M → $704M
Pre-tax IRR49.5% → 59.5%
After-tax IRR38.6% → 46.2%
Payback (after-tax)3.6 years
Total LOM revenueUS$2.377B at $4,200/oz
Cashflow per $100/oz gold move~$55M pre-tax undiscounted

Gold price sensitivity (after-tax NPV5%)

$3,570/oz  –15%$355M
$3,780/oz  –10%$421M
$3,990/oz  –5%$486M
$4,200/oz  BASE CASE$551M
$4,410/oz  +5%$615M
$4,620/oz  +10%$680M
$4,700/oz  SPOT PRICE$704M

IRR positive down to $3,570/oz (–15% base, –24% spot). Viable with opex 107% above budget.

Annual gold production profile (koz)

53
Y1
74
Y2
71
Y3
68
Y4
84
Y5
102★
Y6
35
Y7
24
Y8
24
Y9
24
Y10
13
Y11
Active mining Y1–Y6 — 497koz
Stockpile processing Y7–Y11 — 133koz

Annual cashflow summary (US$M)

Item Y0Y1Y2Y3Y4Y5Y6Y7–11TOTAL
Gold production (koz)5374716884102120573
Gold sales revenue2213062952823474253262,377
Total cash operating costs11113713212010583294982
Initial + sustaining capex27528631313
Pre-tax cashflow–28570151147136224338169986
Income taxes (US + CA)1115173354626842302
After-tax cashflow–28567146126108179274163779
Cumulative after-tax–285–219–73+53+160+340+613+779

Cumulative cashflow turns positive in Year 3. Post-tax payback period is 3.6 years from first production. Year 6 alone generates $274M post-tax cashflow at AISC of only $822/oz.

Taxation & royalties

NSR royalty holderTriple Flag Precious Metals
NSR royalty rate2.5% of net smelter returns
Total NSR royalty payments (LOM)US$36M
Government royaltyNil
US Federal income taxIncluded in model
California state income taxIncluded in model
Property + sales/use taxesIncluded in model
Total taxes (LOM)US$302M

Capital cost breakdown

Processing plant (direct + indirect + infra)US$235.6M
Mining capital (initial + deferred)US$58.7M
— Pre-production mining (capitalised)US$16.3M
Total pre-production capexUS$249M
Company contingencyUS$25M
Working capitalUS$26M
Total funding requiredUS$274M
Sustaining capex (years 1–4)US$38M
Closure / reclamation (net of salvage)US$0 net
Estimate accuracy±10–15% (AACE Class 3)

Processing plant capex sub-breakdown

Electrical installations$51.4M (21.8%)
Mechanical equipment$48.9M (20.7%)
Indirect costs (design + management)$41.0M (17.4%)
Infrastructure + 10km powerline$25.1M (10.7%)
Construction equipment$15.4M (6.5%)
Civil works$16.7M (7.1%)
Structural steel$12.4M (5.3%)

Electrical cost elevated by 10km 34.5kV overhead powerline to SoCal Edison ($10.4M). SAG/Ball mill acquired second-hand (2020-built, unused) — significant capital saving vs new purchase.

Operating cost breakdown (C1 & AISC)

Total mining opex (LOM)US$381M
— Mining ore (avg unit cost)$4.69/t mined
— Mining waste (avg unit cost)$4.28/t moved
Tailings haul & place (LOM)US$74M
Total processing opex (LOM)US$510M
— Power$9.1M/yr ($4.55/t)
— Labour$15.3M/yr ($7.64/t)
— Consumables (cyanide/carbon)$16.1M/yr ($8.03/t)
G&A (LOM)US$92M ($4.45/t)
C1 cash cost (LOM avg)US$1,651/oz
AISC — years 1–6 (mining)US$1,655/oz
AISC — life of mineUS$1,825/oz

Cost structure key insight

Year 6 is the standout year: 102koz at an AISC of only $822/oz, generating $274M post-tax cashflow in a single year — driven by high-grade South Pit ore (avg 2.19g/t) dominating the mill feed. The stockpile phase (Y7–Y11) carries higher AISC of $2,600–$2,877/oz at the low 0.41g/t feed grade, but remains cashflow positive above ~$3,000/oz. Operating cost sensitivity shows the project remains viable with opex up to 107% above budget — a very wide safety margin.

Mineral resource estimate (25 April 2026 — JORC 2012)

Total resource44.5Mt @ 0.76g/t = 1.08Moz
Measured (52%)17.50Mt @ 1.00g/t = 0.56Moz
Indicated (27%)14.60Mt @ 0.62g/t = 0.29Moz
Inferred (21%)12.40Mt @ 0.57g/t = 0.23Moz
North Pit total28.75Mt @ 0.68g/t = 0.63Moz
South Pit total15.76Mt @ 0.88g/t = 0.45Moz
Cut-off grade0.20g/t within $4,200/oz pit shell

Ore reserve estimate (maiden — March 2026 — JORC 2012)

Total reserve20.6Mt @ 0.95g/t = 630koz
Proved (68%)14.1Mt @ 1.06g/t = 480koz
Probable (32%)6.5Mt @ 0.72g/t = 150koz
North Pit reserve13.0Mt @ 0.83g/t = 350koz
South Pit reserve7.6Mt @ 1.15g/t = 280koz
Cut-off grade (reserve)0.25g/t Au at $4,200/oz
Strip ratio3.0:1 (waste:ore) — low

Deposit geology

Deposit typeHydrothermal breccia pipe
Mineralisation styleEpithermal (upper) + Mesothermal (lower)
Host rockFelsite breccia / Precambrian gneiss
Gold formSub-microscopic free gold with pyrite
Two mineralised pipesNorth Pipe + South Pipe — NE–SW elongate
Deposit open at depthYes — North Pit northeast wall
Historical drilling599 holes / 55,609m (1972–1991)
Dateline drilling (2022–25)27 diamond core holes / 4,921m
Total drilling database658 holes / 72,950m

Metallurgy & processing

Processing methodCarbon-in-Leach (CIL) — proven
LOM gold recovery91% confirmed via 2025 test work
Historical operating recovery~92% actual (1988–1993 plant operation)
Recovery consistent down to0.5g/t head grade
Cyanide detoxificationIncluded — tailings fully detoxified
Acid mine drainage riskNone reported — low environmental risk
Metallurgical test programExtensive 2025 program — 6 composites
Assay laboratoryALS Global, Reno Nevada

Important resource context

The 2026 BFS Mineral Resource uses a 0.20g/t cut-off (vs 0.50g/t previously), expanding total tonnes from 27.1Mt to 44.5Mt while reducing average grade from 1.26g/t to 0.76g/t — with total ounces essentially flat at 1.08Moz vs 1.10Moz previously. This is not grade dilution. It reflects the block model capturing bulk-mineable material at lower grade within the optimised $4,200/oz pit shell. The Ore Reserve (the production-relevant number) uses the more conservative 0.25g/t cut-off, yielding 630koz at 0.95g/t — the figure underpinning all financial projections.

Execution timeline

Dec 2025
FEED commenced
GR Engineering Services (GRES) — currently underway
Jan 2026
Bulk earthworks commenced
Site mobilisation and access road upgrades in progress
11 May 2026
BFS released
316-page SK-1300 Technical Report Summary — effective today
Jun 2026
FEED completion + Final Investment Decision
EPC+M contract to be awarded. Financing close expected.
5 Jun 2026
Full site construction commences
Civil contractor mobilises mid-July 2026
Apr 2027
Electrical contractor mobilises
Last major contractor — on critical path (54–64 wk switchrooms)
31 Aug 2027
Dry commissioning complete
Practical completion of processing plant ~1 week later
Q4 2027
First gold production
Ore commissioning and production ramp-up begins
~2033
Peak production year (Year 6)
102koz gold, AISC $822/oz, $274M after-tax cashflow
~2038
End of mine life
Stockpile processing completes mid-Year 11

Pre-construction work — current status

Access road rehabilitationCOMPLETE
Laydown property optioned (incl. 2 water bores)COMPLETE
SAG & Ball Mill acquired (2020-built, unused)COMPLETE
Historical plant foundations assessed for reuseCOMPLETE
GRES awarded FEED contractCOMPLETE
Alvarez & Marsal appointed (project management)COMPLETE
EPC+M contract awardIMMINENT
Project finance close (~US$186M gap)ADVANCED
Final Investment Decision (FID)PENDING

Long lead items — procurement risk

HV/LV MCC switchrooms MOST CRITICAL54–64 wks from PO
MV VSD switchgear57 weeks delivered
Mill motors50 weeks delivered
Variable frequency drives47 weeks delivered
Tailings filters42 weeks delivered
Total construction workforce (peak)~200 personnel on site
Construction accommodation basePrimm Valley Casino Resort, NV

Project risk register

Risk FactorProbabilitySeverity
Gold price sustained decline — most sensitive variableMediumHigh
Permitting — operating under existing Plan of Operations & BLM rightsMediumHigh
Political — Trump administration supportive; regime change risk over 10-yr mine lifeMediumMed-High
Project financing — ~US$186M gap; discussions described as "advanced"MediumMedium
Capital costs — ±15% accuracy band; some unknowns remainMediumMedium
Reagents & consumables pricing (cyanide, grinding media, carbon)MediumMedium
Grade control & reconciliation with block model during operationsLowLow
Infrastructure (road, power, water — all assessed and functional)LowMedium
Process technology — proven CIL, previously operated on site 1988–1993LowLow
Environmental / acid mine drainageLowLow
Groundwater inflow during mining operationsLowLow
Foreign exchange risk (USD reporting / AUD listing)LowLow

NPV upside not included in BFS model

Inferred resources inside pit shell — excluded from reserve, currently treated as waste. Grade control drilling during operations could convert portions to ore, adding production with zero additional capex.
+55 koz potential
Underground target — North Pit sublevel caving (SLC) — open at depth and along strike to the north. Active drilling underway. Not captured in Ore Reserve or financial model.
>50 koz potential
Inferred Mineral Resource inside pit design — 2.8Mt currently treated as waste in the mine plan. Reconciliation during operations may upgrade portions to minable ore.
Up to +55 koz
REE (Rare Earth Element) potential at Colosseum — drill testing recently commenced. Project is located 10km north of Mountain Pass REE mine (US's primary REE producer). Not modelled in BFS.
Exploration upside
Argos Strontium Project — reportedly the largest strontium deposit in the US. Located in San Bernardino County, CA with historical celestite production grading 95%+ SrSO4.
Strategic optionality
Music Valley HREE Project — acquired March 2026. 1,026 claims across Riverside and San Bernardino Counties. USGS-confirmed heavy rare earth element mineralisation. Early-stage exploration.
Exploration upside
Gold price above base case — every $100/oz sustained increase adds ~$55M undiscounted pre-tax cashflow. At today's spot of $4,700/oz, pre-tax NPV5% rises to $999M (+$214M vs base case).
$55M per $100/oz

Analyst bottom line

The bull case is straightforward: A world-class brownfields gold project with a 49.5% pre-tax IRR, 3.6-year payback, existing approvals, proven metallurgy, and substantial NPV upside from above-base gold prices. The project is IRR-positive down to $2,442/oz gold — a level not seen since 2020. Construction risk is materially lower than greenfields peers given the pre-existing plant footprint, acquired SAG/Ball mill, and FEED already underway since December 2025.

The key watchpoints: (1) Financing close — the US$186M+ project finance gap is the single most important near-term catalyst. Management says discussions are "advanced." (2) FID announcement — the Final Investment Decision has not yet been made; the BFS completion is the prerequisite. (3) Political continuity — the Trump administration's explicit support for Colosseum is a current tailwind that introduces regime-change risk over a 10-year mine life. (4) NPCA lawsuit — notably absent from the BFS risk register, suggesting Dateline considers the April 2025 BLM confirmation of existing mining rights as sufficient resolution of the permitting overhang.