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Lode Exchange

Interactive explainers

Two small tools that make the key ideas concrete.

Odds against money spent

Move along the path to see how the chance of a mine, the money spent and the drilling change from step to step.

$1M$10M$100M$1B0.1%1%10%25%50%75%100%Money spent so far (log scale)Chance of becoming a mine →PEAPFSFS1. Grassroots2. Discoverydrilling3. Maidenresource4. Resourceupgrade5. Pre-development6. Developmentand productionResourcesInferredIndicatedMeasuredReservesProbableProbable + ProvenStudy published (an event)Milestone

Stage 3: Maiden resource

Maiden resource

First resource estimate signed by a qualified person. Mostly Inferred, sometimes with Indicated where drilling is denser.

Chance of becoming a mine
About 15% (1 in 7)
Spent so far (cumulative)
About $10M
+$7M since discovery: drilling ~$6M, assays and estimate ~$1M
Drilling
10,000–50,000 m at about 80–200 m spacing
Typical funders
Junior explorers: the start of the funding gap
Show as a table
MilestoneChance of a mineSpent so far (cumulative)Drilling
Grassroots explorationAbout 0.1% (1 in 1,000)About $0.3M
Starting spend: mapping, sampling, geophysics		None yet
Discovery drillingAbout 3% (1 in 30)About $3M
+$3M since grassroots: drilling ~$2M, surveys and access ~$1M		2,000–5,000 m, scattered target holes
Maiden resourceAbout 15% (1 in 7)About $10M
+$7M since discovery: drilling ~$6M, assays and estimate ~$1M		10,000–50,000 m at about 80–200 m spacing
Preliminary economic assessment (PEA) publishedAbout 30% (1 in 3)About $20M
+$10M since the maiden resource: drilling ~$8M, metallurgy ~$1M, PEA study ~$1M		Infill toward about 40–100 m spacing, first metallurgy
Pre-feasibility study (PFS) published: Probable reservesAbout 45% (about 1 in 2)About $40M
+$20M since the PEA: drilling ~$10M, testwork and environment ~$5M, PFS study ~$5M		Indicated spacing, plus geotechnical, hydrogeology and condemnation holes
Feasibility study (FS) published: Proven reservesAbout 65% (2 in 3)About $70M
+$30M since the PFS: drilling ~$10M, testwork and permits ~$5M, FS study ~$15M		About 15–50 m spacing in the early mine plan
Construction decisionAbout 85%About $120M
+$50M since the FS: early engineering and orders ~$30M, permits and community ~$10M, financing ~$10M		Mostly complete; some grade-control and near-mine drilling
ConstructionAbout 95%About $500M
+$380M since the build decision: plant ~$200M, mine and fleet ~$100M, power, water and tailings ~$80M		Grade control and near-mine exploration
Producing mineIt is a mineAbout $1B
+$500M during the build: rest of construction ~$400M, ramp-up and working capital ~$100M		Ongoing grade control and reserve replacement
Illustrative path for a mid-size open-pit gold or copper project. Money is cumulative and on a log scale; the chance axis is stretched so each step gets room. Chances are mid-range figures for a project that has reached each milestone. Each of the six stages runs from one published event to the next. Studies are events: Probable reserves exist from the day a PFS is published, and Proven reserves usually from the FS. Real projects vary widely. Not data and not a forecast.

Tonnes times grade

Contained metal is a starting point, not a valuation. Change the inputs to see why.

10 Mt
1.5 g/t gold
2,000 $/oz
90 %
50 $/t

Contained gold

482,261 oz

10 Mt × 1.5 g/t ÷ 31.1035 g per troy ounce

  • Value in the ground$965M
  • After recovery losses$868M
  • After operating costs$368M

Only about 38% of the in-ground value is left after recovery and operating costs, and that is before capital cost, tax, royalties and the time value of money.

Illustrative arithmetic with invented inputs, not a valuation.