Model integrity
The calculator is an independent reconstruction from public information, primarily the NioCorp 2026 Elk Creek Feasibility Study. It distinguishes OFFICIAL published figures, RECONSTRUCTED quantities and calculations, and USER ASSUMPTIONS. These classifications help visitors distinguish reported facts from modeling choices.
The base case reconciles to selected published NPV and revenue anchors. This agreement uses explicit calibration; it does not independently reproduce NioCorp’s undisclosed financial model. Automated checks cover base-case reconciliation, unit conversions, scenario consistency, commodity attribution, sensitivities, and export consistency. Numerical comparisons use defined absolute or relative tolerances appropriate to their scale. Rounded display values are checked separately from underlying calculations.
Automated verification
The figures above are generated from a complete passing release-validation run against the private engine. Registered test cases and separately named financial check groups are different measures, not individual assertion counts. A separate 130-case original compatibility suite and 59-case migration suite also pass. Their coverage overlaps; no combined unique-test total is claimed.
Testing covers financial reconciliation, unit conversions, inputs, scenarios, recoveries, attribution, sensitivities, saved-scenario restoration, charts and exports. Private-engine results are compared with the preserved original implementation. Some checks establish internal consistency rather than independent correctness of the economic assumptions.
Before this production migration, hosted staging testing compared 47 financial responses and 107 requested job results exactly with the original engine. Browser acceptance covered 41 distinct exports and 33 responsive viewport observations. Controlled failures verified retained inputs, disabled exports and recovery. These are bounded staging observations, not independent certification or a claim that every production condition has been tested.
Architecture & maintainability
The public calculator sends scenario inputs to a same-origin server calculation service. The private financial engine runs in a Node.js server function and returns requested numerical results. Browser files handle controls, display, chart interaction and local scenario storage; they contain no executable financial-model implementation or local calculation fallback.
Reference data, validation, calculation, transport and presentation have separate responsibilities. The interface retains its financial scenarios, charts, exports and disclosures. Saved scenarios remain in this browser, while calculation requests necessarily transmit their inputs to the service. Changes still require regression testing.
Reproducible release
The release separates an allowlisted public asset build from the private server function. Private model modules, documentation, tests and engineering diagnostics are excluded from the public directory. Repeated local builds produce identical public assets. Hosted staging inspection checked delivered JavaScript against the reviewed build and tested selected private-file paths.
Deployment configuration and release metadata are controlled. Private documentation records verification, deployment and rollback, with the original production version retained privately. The application declares no third-party runtime package dependencies; provider deployment tooling and server infrastructure remain external dependencies. Build reproducibility does not guarantee identical behavior in every environment.
Dependency & security hygiene
The calculation service validates requests, bounds resource use and returns requested results without serving private source files. The public calculator and API are intentionally usable by visitors; privacy applies to the implementation, not secrecy of scenario outputs. Source checks cover unsafe links, escaped chart metadata, spreadsheet-formula handling and accidental disclosure.
Controls and selected exposure checks are bounded engineering checks, not proof against every attack. No independent penetration test, configured continuous-integration pipeline, linter or type checker is claimed. Hosting limits can interrupt service, and no public application can be represented as free of all security risk.
Documentation & technical handoff
Private documentation covers architecture, model and data definitions, deployment, testing, known limitations, and release history. Major model inputs and derived quantities are documented by source, unit, classification, transformation, and model role. This material supports maintenance and technical handoff without publishing the detailed implementation.
A handoff still requires authorized access, a review of source and data rights, and an assessment of the model’s assumptions. This page does not establish legal ownership or provide an acquisition, licensing, or audit opinion.
Release history
Every recorded version from v1.0.0 on October 3, 2026. Dates show the first recorded release in New York time; later revisions under the same version are noted.
View all 25 releases
- Moved financial calculations to a private server engine behind the public calculator's same-origin API, without changing financial arithmetic or reference assumptions.
- Retained existing controls, scenarios, charts, exports, design and disclosures; added asynchronous loading, retry and unavailable-result handling without a browser calculation fallback.
- Updated Technical Assurance and release metadata to describe the server architecture, its public disclosure boundary and bounded verification evidence.
- Retained the original production version privately for rollback.
- Refined the Technical Assurance page with a clearer verification summary, separate release metadata and consistent reading spacing.
- Added section navigation and a return-to-top link, with responsive layouts and reduced-motion support.
- Preserved every assurance explanation, limitation, statistic, contact link and recorded release.
- Organized the calculator footer into aligned identity, source and release information, support and contact details, and matching information buttons.
- Preserved the Buy Me a Coffee link, email, creator credit, official study source and important notice, with a stacked layout for phones.
- Expanded the Technical Assurance release history to every recorded version, beginning with v1.0.0 on October 3, 2026, with dates and verified changes.
- Added a readable version-and-date timeline generated from a validated release record; explicitly noted later revisions that reused a version number.
- Kept financial calculations, source benchmarks and market prices unchanged.
- Added the Technical Assurance page and a footer button, with matching light and dark themes, mobile layout and calculator return navigation.
- Published verified automated test results and named financial-model checks, a high-level architecture overview, reproducibility evidence and explicit assurance limitations.
- Created private maintenance and handoff documentation covering architecture, model inputs, deployment, testing, limitations and release history.
- Added repeatable release-artifact and public-disclosure checks; clarified the distinction between a private repository and browser-delivered application files.
- Opened the assurance footer link in a separate tab to retain the calculator's current working scenario.
- Kept financial calculations, source benchmarks and market prices unchanged.
- Matched the RECONSTRUCTED label's text color to the OFFICIAL and USER ASSUMPTIONS labels in both themes.
- Updated release metadata and browser assets without changing financial calculations.
- Aligned the header with the main calculator content and refined its spacing and responsive layout.
- Gave the introductory title full width and organized model actions, disclosures and active-scenario information into clearer rows.
- Preserved export, print, reset, official-site and theme controls while improving tablet and phone wrapping.
- Simplified the heat-map controls with compact X/Y headings, shorter Min/Max labels and explicit USD/kg units.
- Removed duplicated axis cards and placed one clear product mapping above the grid, outside horizontal scrolling.
- Preserved all cell values, keyboard inspection, product swapping, range reset and mobile scrolling; updated presentation regressions.
- Added phone scrolling guidance for the price curve and heat map, including the heat map's persistent Y-price labels.
- Refined the price-preview marker so it does not obscure the plotted curve.
- Added a price explorer with numeric and slider previews, current-price and FS-price shortcuts, and an explicit action to apply an explored price.
- Rounded price-axis labels for readability while retaining exact inspected prices, NPV values and scenario changes.
- Added curve display choices and clearer inspection guidance, markers and keyboard movement.
- Clarified heat-map X columns and Y rows, product names, ranges and directions; added swap and range-reset actions.
- Added regression checks for preview application, isolation, scandium adjustments, axis swaps, exact grid values and extreme or invalid ranges.
- Confined waterfall horizontal scrolling to the diagram rather than the entire chart panel.
- Kept the legend, explanation and complete exact-values table fixed outside the scrolling area.
- Added regression protection for the scroll boundary and all exact waterfall values.
- Reworked the NPV waterfall to show the FS total, nonzero effects and scenario total without empty-stage clutter.
- Used a taller plot, cleaner currency ticks and proportional bars; retained signed amounts and endpoint markers for small effects.
- Corrected selection outlines to follow visible bars and labels instead of invisible full-height hit areas.
- Preserved all eleven exact stage values and added geometry and reconciliation checks across both tax bases, products and extreme scenarios.
- Corrected CSV and print summaries to describe effective valuation assumptions during commodity isolation.
- Included the isolated product and annual scandium pricing adjustment, while keeping dormant working inputs distinct in JSON.
- Made the named Current Market reference consistently load and reset FS advanced defaults; dedicated market-price presets still retain advanced assumptions.
- Added regressions that reconstruct valuations from serialized CSV assumptions and check reference selection, reset and preset behavior.
- Corrected the SEG carbonate snapshot from $8.95/kg to the technical report's direct $8.97/kg benchmark, matching the existing FS anchor.
- Linked titanium, SEG and heavies fallback references directly to the official technical-report PDF and identified the supporting table and page.
- Preserved the dated scandium study blend and original FS pricing schedule; expanded fallback, provenance and rounding validation.
- Added a stored last-updated date synchronized with the model release, separate from export-generation timestamps and page visits.
- Added the feedback email link and reorganized the footer into aligned source, version, credit, support, contact and notice rows.
- Right-aligned contact details on larger screens while retaining responsive phone layouts and the Buy Me a Coffee link.
- Clarified the currency basis as FY Q1 2027 constant USD.
- Expanded the annual chart vertically and replaced awkward axis figures with cleaner USD ticks, including negative and extreme ranges.
- Displayed signed commodity NPV impacts as currency amounts that update with the active price scenario.
- Centered the market-status indicator and retained reduced-motion support.
- Updated creator credits to Designed, audited and maintained by the creator, with OpenAI Codex development attribution and the existing Reddit link.
- Changed the heat map to a higher-contrast red-to-green scale with a matching legend and distinct reference markers.
- Replaced non-scandium outside price observations older than the FS effective date with the corresponding FS benchmarks.
- Used the observation period rather than a later publication date; handled month-only and ranged references conservatively without rewriting saved provenance.
- Retained the explicitly selected scandium blend and clarified unverified pricing terms without claiming the chemical product itself differs.
- Added cutoff, date-boundary, source-display and historical-snapshot regressions.
- Displayed both Weir and NioCorp study sources for the scandium midpoint reference in the main market table.
- Verified and retained the then-current SEG snapshot comparison; that snapshot was subsequently corrected in v1.6.5.
- Added the red market-snapshot indicator with reduced-motion support while retaining the manually updated, non-live-feed disclosure.
- Removed dashed waterfall connectors and added a regression preventing their return.
- Added independent mineral recovery controls using six disclosed FS economic-model recovery rates.
- Made relative percentage changes stackable between minerals and bounded actual recovery to 0–100%; left undisclosed carbonate recovery controls unavailable.
- Preserved legacy scenarios and carried recovery assumptions through saved scenarios, comparisons, exports and print summaries.
- Kept recovery changes when applying price presets and restored FS rates through recovery, advanced-assumption and model resets.
- Refined waterfall connectors to skip zero-effect stages and added recovery, persistence, export and reconciliation regressions.
- Populated the previously empty market snapshot with eight maintainer-supplied dated price references.
- Distinguished market references, the blended scandium study assumption and FS fallback assumptions rather than treating them all as spot quotes.
- Added month-only age ranges, study date ranges, separate publication dates, additional source references and explicit conversion rounding.
- Preserved source details in exports and print, and refined the header to THE ELK CREEK PROJECT.
- Added the Current Market section, manually maintained dated and sourced snapshot inputs, age warnings and an implied-NPV view.
- Required all eight complete price references before activation; the initial snapshot intentionally contained no prices or dates.
- Added provenance, saved market-scenario identity, custom labels and base-case calibration reconciliation.
- Integrated market assumptions with existing scenarios, charts, exports and print without introducing an automatic pricing feed.
- Made charts inspectable by hover, tap and keyboard, with pinned values, clear-selection controls and accessible descriptions.
- Improved numerical stability so small price movements remain measurable in extreme scenarios; expanded comparison and chart regressions.
- Refined product colors for clearer separation and matched price-control element badges to their chart colors.
- Clarified the header's 2026 FS calculator description, removed the EC header logo and updated creator/development credits.
- Added optional Buy Me a Coffee support links to the notice, results area and footer, then moved the notice link near the top.
- Added Light/Dark controls, saved theme preferences, early theme application, cross-tab synchronization and storage-failure handling.
- Applied theme-aware controls, charts, tables, notice and print appearance; added theme regression checks.
- Refined the neutral visual palette, serif typography and source-link treatment while preserving sans-serif footer and element labels.
- Added header and footer creator credits with the existing Reddit profile link.
- Further revisions on October 4 added green gains/red losses, fitted element labels including Heavies, and capped displayed decimals while retaining calculation precision.
- October 4 revisions also added consistent product chart colors, clearer official-site emphasis and stable price-slider ranges that reach their right endpoint.
- October 4 revisions improved the mobile entry notice and decimal input keyboards and added NPV Calculator Tool to the page title.
- Improved tornado labels, responsive revenue bars, numeric currency axes, zero baselines and exact waterfall values.
- Clarified scandium curve adjustments, adaptive heat-map precision and reference markers, and annual-series filtering and empty states.
- Added chart regressions, refined phone summary layouts and introduced a local header/favicon mark.
- Clarified unofficial NioCorp Elk Creek branding and added official-website links to the page and entry notice.
- Corrected proportional scandium schedule sensitivity and exposure shares, and clarified annual pricing adjustments in the methodology.
- Added direct scenario comparison attribution and shared bounds for prices, assumptions, movements and sensitivity grids.
- Validated and bounded saved scenarios, neutralized spreadsheet-formula strings in CSV, and expanded model, state, export and stress regressions.
- Grouped charts and metric tables, improved price-field alignment and keyboard tabs, and retained fallback export downloads.
- Made the entry notice recur on page entry, refresh and history return, and clarified unavailable sensitivities and price thresholds.
- Earliest retained controlled snapshot of the independent eight-product Elk Creek NPV calculator.
- Included official FS anchors, reconstructed annual cash flows, commodity price controls, advanced assumptions and pre-tax/after-tax valuations.
- Included revenue and sensitivity charts, price curves, two-product heat maps, scenario comparisons, local scenario storage, CSV/JSON exports and print summaries.
- Documented methodology, source assumptions, data-audit notes, reconstruction limitations and the independent-model disclaimer; included automated financial checks.
Known limitations
Project economics remain estimates. Cash flows, timing, costs and tax treatment are reconstructed and may differ from the company’s internal model. Current Market uses manually maintained, dated references and labeled fallback assumptions, not a real-time feed. Scenarios are hypothetical. Published IRR and payback describe the FS base case; project NPV is not a company equity valuation or share-price forecast.
Calculation requires network and server availability. Browser viewport checks used Chromium emulation, not every physical device or browser. Final native print/PDF output and certified provider cold-start or billed-duration metrics were not established by staging testing. Passing checks do not guarantee investment outcomes or imply certification by NioCorp, qualified persons, regulators or independent auditors.
Repository & disclosure boundary
The financial-model implementation and detailed technical documentation remain on the private server or in private maintenance records. They are not browser downloads. Delivered interface code, public source references, scenario inputs and returned financial results remain inspectable. This boundary protects the implementation without treating reported outputs as secret.