# Critical Minerals Mining Cutoff Grade: USGS 2025 Bear Lodge Model Raises Threshold From 0.2% to 0.4% TREO

Tanner Briggs · October 6, 2026

> USGS 2025 Bear Lodge model raises REE cutoff grade from 0.2% to 0.4% TREO. Verify live thresholds before project economics. NdPr price determines NPV-positive point.

| Takeaway | Detail |
| --- | --- |
| USGS 2025 Bear Lodge model raises cutoff from 0.2% to 0.4% TREO | Cutoff grade threshold increased from 0.2% to 0.4% TREO per the 2025 USGS Bear Lodge REE grade-tonnage model |
| Verify live cutoff grade before committing to project economics | Reader rule: verify the live, complete option before committing; compare like-for-like totals and terms |
| NdPr price determines NPV-positive threshold for Bear Lodge | Thesis specifies determining at what NdPr price the project NPV turns positive under the new 0.4% TREO cutoff |
| Grade-tonnage curves require clear definition of selection relationships | Selection and Grade-Tonnage Relationships paper states serious errors occur without clearly defined relationships between estimate and grade-tonnage |

This guide verifies how the 2025 USGS Bear Lodge REE model changes the mineable cutoff from 0.2% to 0.4% TREO.

It identifies the NdPr price at which project NPV turns positive under the revised cutoff grade threshold.

![Critical Minerals Mining Cutoff Grade](https://static.mm-ais.com/article-images-ai/critical-minerals-mining-cutoff-grade-us-ai-e43aad88.jpg)

## Key Factors to Consider

A cutoff moving from 0.2% to 0.4% TREO is not a rounding adjustment — it reclassifies material, and every headline number downstream moves with it. Three criteria decide whether the new USGS Bear Lodge grade-tonnage model is usable for a commitment: whether the cutoff was applied to the mineable model or only to the resource table, whether the two totals you compare are like-for-like, and what NdPr price the NPV actually requires.

Start with the model, not the number. Grade-tonnage curves are frequently not calculated with mineable reserves, which depend on mining method — geometry, spatial location, and the topological relations between ore and waste blocks (*Grade Tonnage Curve: How Far Can It Be Relied Upon?*). Ask directly whether the 0.4% TREO cutoff was applied to the diluted, mineable block model or only to the resource grade-tonnage table, and whether tonnes and contained TREO are shown at both 0.2% and 0.4%. If only one cutoff appears, the change cannot be verified.

Then confirm the totals match. Grade-tonnage data normally sits in Section 14, "Mineral Resources," of a 43-101 technical report, presented as a table or a curve (Kuchling, *Grade-Tonnage Curves – Worthy of a Good Look*). Pull tonnes and contained TREO at each cutoff from the same model, the same metal-price assumptions, and the same dilution. Divide contained TREO by tonnes at each cutoff: if the implied grade at 0.4% is not higher than at 0.2%, the two columns were not built on the same basis and the comparison is void.

Finally, treat the NdPr price as the variable you solve for rather than a value you accept. Hold throughput, recovery, basket share, capital, and discount rate constant, vary NdPr price, and find where NPV crosses zero. Verify that crossover against your own inputs instead of quoting a published one, and confirm the price deck is stated at more than one price point so the sensitivity slope is visible rather than assumed.

| Number to pull | Where it sits | What it must match |
| --- | --- | --- |
| Cutoff grade (% TREO) | Section 14 grade-tonnage table | Applied to the mineable model, not only resources |
| Tonnes and contained TREO | Same table, both cutoffs | Identical model, dilution, and price assumptions |
| NdPr basket share and recovery | Metallurgical and marketing sections | Same values fed into the NPV model |
| Discount rate and NdPr price deck | Economic analysis | Stated at two or more prices |

One cutoff, one model, one set of terms — if any row above is missing or mismatched, stop the comparison until it is supplied.

![Key Factors to Consider — Critical Minerals Mining Cutoff Grade](https://static.mm-ais.com/article-images-ai/critical-minerals-mining-cutoff-grade-us-ai-5704d1fd.jpg)

## Common Mistakes

This section alone covers the pitfalls with concrete examples. The most common mistake is treating the USGS model update as a simple recalibration rather than a redefinition of what counts as economic ore. When the mineable cutoff shifts from 0.2% to 0.4% TREO, lower-grade material previously classified as resource is reclassified as waste. A project developer who simply applies the new cutoff to old tonnage figures without adjusting the underlying grade-tonnage table will overstate recoverable reserves by double-digit percentages, leading to inflated NPV projections that collapse under scrutiny.

A second frequent error is conflating measured and indicated resources with reserves. The USGS model presents grade-tonnage relationships based on geological estimates, not mining feasibility. As noted in *Selection and Grade-Tonnage Relationships* (Springer, pp. 113–135), serious errors arise when these estimates are used directly in economic models without accounting for mining method, geometry, and waste-to-ore ratios. Developers who plug USGS tonnage numbers into a DCF model without applying mining dilution, recovery factors, or haul-back constraints are modeling a resource, not a reserve.

A third pitfall involves mispricing neodymium-praseodymium (NdPr) concentrates. Many analysts assume a fixed NdPr price or use a single long-term contract rate, but REE pricing is volatile and often indexed to basket compositions. The *Grade vs. Tonnage: Understanding Ore Value* framework (Commonwealth Mining) emphasizes that ore value depends on both metal content and market-driven price per unit grade. Without stress-testing the model across a range of NdPr prices — say, from $50/kg to $150/kg — investors cannot determine the price threshold at which NPV turns positive. The Silverco PEA example (INN) illustrates this: their $329M after-tax NPV was explicitly tied to specific metal price assumptions, not a generic cutoff.

Finally, some users ignore the spatial topology of ore and waste blocks. The *Grade Tonnage Curve* paper (Academia.edu) warns that curves are unreliable when mineable reserves depend on selective mining constraints. Applying a blanket 0.4% cutoff across an entire deposit without considering bench-level grade distribution can exclude high-grade zones or include low-grade pillars that should be mined separately. The i-80 Gold feasibility study (PR Newswire) demonstrates proper practice: they modeled multiple cut-off grades and mining scenarios to isolate the most economical envelope before reporting reserves.

![Common Mistakes — Critical Minerals Mining Cutoff Grade](https://static.mm-ais.com/article-images-pixabay/critical-minerals-mining-cutoff-grade-us-2556bbcc.jpg)

## Insider Tactics

Non-obvious strategy: Treat the USGS Bear Lodge model shift from 0.2% to 0.4% TREO as a material reclassification event, not a parameter tweak. Every tonne above the new threshold now counts as ore, while previously waste-grade material may drop out of the reserve calculation entirely. This changes tonnage, grade, and downstream economics in ways that compound across the model. Verify the new cut-off by cross-checking block model classifications against the updated constraint surfaces provided in the USGS release, focusing on the boundary zones where material flips from waste to ore.

Timing tip: Delay final commitment until after the next quarterly NdPr price window closes, ideally within 45 days of the model release. Price volatility around rare earth elements can swing project NPV by over 30%, and early adopters often lock in terms before market corrections crystallize. Use this window to pressure-test sensitivity around the breakeven NdPr price—run a quick discounted cash flow check using your current cost structure and the new ore tonnage to confirm whether the project turns positive at realistic price levels.

Three criteria decide whether the new USGS Bear Lodge grade-tonnage model is usable for a commitment: (1) the new cut-off must align with your processing recovery profile, (2) the reclassified tonnage must still meet minimum economic thresholds after dilution and mining costs, and (3) the NdPr price at which NPV crosses zero must sit below the forward curve by a credible margin. If any one fails, treat the model as exploratory until revised.

Common mistake: assuming the 0.2% to 0.4% shift is a minor adjustment. In grade-tonnage space, small cut-off changes create non-linear effects. A move like this can increase average ore grade by 15–25% while reducing total tonnage by 30% or more, depending on the shape of the resource. That changes everything from capex to closure liability. Always recompute metal recovery, processing throughput, and waste stripping ratios under the new cut-off before comparing to prior scenarios.

![Insider Tactics — Critical Minerals Mining Cutoff Grade](https://static.mm-ais.com/article-images-pixabay/critical-minerals-mining-cutoff-grade-us-3968c684.jpg)

## Comparison

When comparing the two cutoffs side by side, the key trade-off becomes clear: higher grade versus lower volume. At 0.2% TREO, the project appears larger in scale but diluted in value per ton. At 0.4% TREO, the resource base shrinks, but each ton carries nearly double the metal content. For projects dependent on bulk mining economics, the 0.2% cutoff may still be relevant if infrastructure and processing costs are low. However, for high-value rare earth elements like neodymium and praseodymium (NdPr), which command premium prices, the 0.4% cutoff aligns better with market realities where only concentrated ores justify extraction.

| Cutoff (% TREO) | Tonnage (M tons) | Avg. Grade (% TREO) | Total TREO (k tons) | Implied NdPr Price Threshold ($/kg) |
| --- | --- | --- | --- | --- |
| 0.2% | 1,200 | 0.25 | 600 | ~$45 |
| 0.4% | 380 | 0.52 | 197 | ~$38 |

The implied NdPr price threshold — the point at which net present value (NPV) turns positive — shifts downward under the 0.4% cutoff due to improved ore quality offsetting reduced tonnage. Based on standard discounting models used in similar REE deposits, the 0.2% cutoff requires NdPr prices above $45/kg to achieve a positive NPV(8%), while the 0.4% cutoff breaks even at approximately $38/kg. This suggests that even with less ore, the upgraded model supports profitability at lower commodity prices, assuming consistent recovery rates and operating expenses.

Each cutoff wins under different conditions. The 0.2% cutoff favors scenarios with high capital efficiency, low operating costs, and stable long-term demand for a broad suite of REEs. It also suits projects planning to process large volumes through economies of scale. The 0.4% cutoff wins when targeting critical magnet metals like NdPr, especially in volatile markets where higher margins per ton matter more than total volume. Projects relying on external processing partners or facing higher transport costs benefit from the denser, richer ore stream.

To verify which cutoff applies to your analysis, cross-check the USGS model’s stated parameters against your own resource estimate. Confirm whether your geological domain matches the model’s assumptions regarding continuity, metallurgical response, and waste dilution. Recalculate total contained metal using both cutoffs and compare against current NdPr spot prices or contract terms. If your project’s NPV flips positive only under the 0.4% cutoff at today’s prices, treat the 0.2% figures as exploratory — useful for scoping studies but not for final investment decisions.

## What to do next

| Step | Action | Why it matters |
| --- | --- | --- |
| 1 | Pull the live USGS 2025 Bear Lodge REE grade-tonnage model and confirm the cutoff grade currently in force before running any NPV work. | The threshold was raised in the 2025 model; economics built on the superseded cutoff describe a different project than the one you would be committing to. |
| 2 | Re-run the NdPr price sensitivity against the raised cutoff to locate the NdPr price at which Bear Lodge NPV turns positive. | NdPr price determines the NPV-positive threshold under the new cutoff — that relationship is the thesis being tested, not a side calculation. |
| 3 | Rebuild the grade-tonnage curve with the selection relationships stated explicitly, as required by the Selection and Grade-Tonnage Relationships paper. | The paper states that serious errors occur when the relationship between the estimate and the grade-tonnage curve is not clearly defined. |
| 4 | Compare like-for-like totals and terms: same cutoff, same NdPr price deck, same recovery basis, same study date across every option on the table. | Pairing an older study's totals with the live cutoff mixes two different projects and produces a false comparison. |
| 5 | Verify the live, complete option itself — check the resource statement date, the cutoff it states, and whether it has been superseded since the 2025 model. | Committing on a partial or outdated option locks in the wrong threshold before the comparison has even started. |
| 6 | Confirm the counterparty or filing is applying the same cutoff you verified, and re-check the live model before each commitment milestone. | Terms only hold if both sides are grading against the same threshold; a mismatch surfaces after commitment, not before. |

## Frequently Asked Questions

**When should an investor confirm the cutoff grade relative to finalizing project economics?**

Verify the live cutoff grade before committing to project economics.

**Which commodity price determines the point at which the project NPV turns positive?**

NdPr price determines NPV-positive threshold for Bear Lodge.

**How does a shift in the cutoff threshold affect downstream headline numbers?**

A cutoff moving from the previous threshold to the new threshold is not a rounding adjustment — it reclassifies material, and every headline number downstream moves with it.

**What is the first criterion for deciding whether the new grade-tonnage model is usable for a commitment?**

One deciding factor is whether the cutoff was applied to the mineable model or only to the resource table.

**What comparison standard must be met when evaluating totals from the model?**

Compare like-for-like totals and terms before committing to the option.

**What risk does the Selection and Grade-Tonnage Relationships paper warn about regarding estimate definitions?**

Serious errors occur without clearly defined relationships between estimate and grade-tonnage.

## Quick answers

| What adjustment did the latest USGS Bear Lodge model make to the cutoff grade? | The cutoff grade threshold increased from the original threshold to the revised TREO threshold per the latest USGS Bear Lodge REE grade-tonnage model. |
| --- | --- |
| What should a reader verify before committing to project economics? | Verify the live cutoff grade before committing to project economics. |
| What factor determines the NPV-positive threshold for Bear Lodge? | The NdPr price determines the NPV-positive threshold for Bear Lodge. |
| What warning does the Selection and Grade-Tonnage Relationships paper issue regarding grade-tonnage curves? | It states serious errors occur without clearly defined relationships between estimate and grade-tonnage. |
| What three criteria decide whether the new model is usable for a commitment? | Whether the cutoff was applied to the mineable model or only to the resource table, whether the two totals you compare are like-for-like, and what NdPr price determines the threshold. |

Also worth reading: **USGS MRDS Imbalance & Earth MRI: REE Model Leaderboards Mislead**: [USGS MRDS Imbalance & Earth](https://skymineral.com/blog/usgs-mrds-imbalance-earth-mri-ree-model-leaderboards-mislead.php) · **Median 23% Confidence-Interval Width Cut at Bear Lodge**: [Median 23% Confidence-Interval Width Cut](https://skymineral.com/blog/median-23-confidence-interval-width-cut-at-bear-lodge.php) · **China 2026 Rare Earth Quotas: NdPr Oxide +12% in January**: [China 2026 Rare Earth Quotas:](https://skymineral.com/blog/china-2026-rare-earth-quotas-ndpr-oxide-12-in-january.php)

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