Deposit

Spar Lake

Also known as Troy Mine

A mineral deposit recorded by the USGS sediment-hosted copper database, at Montana, United States. The compilation classifies it as a Revett-type copper deposit. Its reported host rocks are Quartzite. Minerals reported present include chalcopyrite, bornite, pyrite, galena, sphalerite, hematite, barite, chlorite.

recognition basis: authoritativeDatabase
realm: northAmerica

What this record is, and who says so

Recognised on the basis of

Authoritative database

A curated deposit database published by a scientific institution, in which inclusion is itself a documented editorial decision with stated criteria.

A deposit is an occurrence of sufficient size and grade that it might, under the most favourable circumstances, be considered to have economic potential. Lithoen records that a named authority made that judgement. It is not a statement that anything here is recoverable, and it is not a resource or a reserve.

Commodities documented here

Copper (commodity)documented association
The compilation reports a grade for this metal at this deposit. Lithoen records the documented association and infers nothing about how it would be worked.
Silver (commodity)documented association
The compilation reports a grade for this metal at this deposit. Lithoen records the documented association and infers nothing about how it would be worked.

Reported figures, and what each one is

A sample assay, a deposit average, a compiler total and a reported reserve are different quantities. Each figure below carries which one it is; none of them is a current resource or reserve.

58 Mt

Compiler total, for modelling

A sum assembled by a database compiler from production plus reserves plus resources at the lowest available cut-off, so that deposits can be compared in a grade-and-tonnage model. It is not a resource, not a reserve and not production; it is a modelling quantity, and the USGS databases Lithoen reads define their tonnage exactly this way.

The usgs sediment-hosted copper database reports an ore tonnage of 58.0 million tonnes for Spar Lake.

0.8 wt%m Copper

Deposit average

An average grade attributed to a whole deposit by a compiler, over a tonnage defined by that compiler at a stated cut-off. Not a measurement of anything: a summary of an estimate.

The usgs sediment-hosted copper database reports a copper grade of 0.8 weight percent for Spar Lake.

58 g/t Silver

Deposit average

An average grade attributed to a whole deposit by a compiler, over a tonnage defined by that compiler at a stated cut-off. Not a measurement of anything: a summary of an estimate.

The compilation reports a silver grade of 58.0 grams per tonne of ore for Spar Lake. The field is defined as the average grade of silver for the deposit, stated as grams per metric ton of ore.

The source records behind this

What one row of a published dataset was taken to mean, and why. The original record stays traceable after reconciliation.

Sediment-hosted copper deposits of the world (USGS OFR 03-107), record 664
Named there
Spar Lake
The source calls it
deposit
Lithoen reads it as
deposit (stated)
The usgs sediment-hosted copper database states what one of its rows is, and this row is read as the deposit the compilers named. The compilation is a database of sediment-hosted copper deposits.
Read and refused
- grade and tonnage columns with no value — The compilation writes "(no value)" or leaves the field empty where the information was not available. Reading an empty field as zero would publish a measurement nobody made.

How this is mapped

One published representation of where Spar Lake is. Each is one interpretation, by one identified source, at one scale — not the shape of the thing itself.

Representative point
Point · 1 positions
A single position standing for something that is not a point. It exists so a feature can be shown on a map or listed by location, and it asserts NOTHING about extent. A representative point for a 2,000 km province is a label anchor, not a location.
A representative point for Spar Lake from the USGS sediment-hosted copper database. It marks where the compilation places the deposit; it is not a boundary, not a shaft, and implies nothing about the body's extent.
Boundary certainty
ApproximateThe position is known only within a distance much larger than the line width on any map that shows it. Drawing it thinner does not make it better known.
Status of this geometry
disputedThe status of the geometry, which need not match the status of what the entity’s claims assert.
Dataset
Sediment-hosted copper deposits of the world (USGS OFR 03-107)Cox, D.P., Lindsey, D.A., Singer, D.A., Moring, B.C., and Diggles, M.F., 2003, Sediment-hosted copper deposits of the world: Deposit models and database: U.S. Geological Survey Open-File Report 03-107, doi:10.3133/ofr03107.
What was done to this geometry
- By Lithoen — Rounded to 4 decimal places. The compilation computed its decimal degrees from authored degrees-minutes-seconds columns, and the further digits are conversion residue rather than knowledge.
- Before it reached Lithoen — The compilation computed these decimal degrees from the degrees-minutes-seconds columns its compilers authored.

How this record is known

8
Settled consensus: Cited as the accepted position of the discipline.; 1
Open questions: Sourced statements that the answer is not currently known.

9 of 9 claims on this page cite at least one registered source. Counts describe how each statement is known, not how likely it is to be true.

What Lithoen records

Each claim states how it is known and cites its evidence.

Establishedstprov "Montana" and latitude 40.2303 N cannot both be right; both are carried, neither is corrected

Derived by Lithoen

The compilation row for Spar Lake contradicts itself. It states the deposit is in Montana and gives it a latitude of 40.23 degrees north, 6.6 degrees south of the next most southerly of the eight other rows the same compilation places in Montana, and about 730 km from the nearest of them. Its longitude sits among theirs. Lithoen holds both fields as the source wrote them and does not know which is wrong: the coordinate may be mistaken, or the state may be. It has not moved the point, because correcting a coordinate to where a deposit is thought to be would replace a source’s error with Lithoen’s invention. The point should not be used to place this deposit until the conflict is resolved against a source that resolves it.

Not stated verbatim by the source — derived: min(|lat(Spar Lake) − lat(other Montana rows)|) = |40.230 − 46.867| = 6.64° ≈ 730 km

The conflict is arithmetic on the compilation’s own fields. Stating it as a derivation keeps it as what it is — Lithoen noticing an inconsistency — rather than as a correction of the source, which Lithoen has not made and cannot make.

assertion basis: LITHOEN_DERIVED
method: Comparison of the nine rows the compilation itself assigns to Montana. The argument is internal to the source and needs no outside authority: whatever Montana’s bounds are, one row of nine sits 730 km from the rest.
non uniqueness: The alternate name the row carries, "Troy Mine", and its stated host formation, the Revett, are both associated with north-western Montana in the literature. That is a reason to suspect the latitude rather than the state, and it is a suspicion, not a determination.
precision note: This is the only such conflict found among the deposit points in this corpus. It was found by integration work rather than by a validator, because no rule in this corpus compares a coordinate with a stated jurisdiction, and none is added: doing so would need boundary data Lithoen does not hold.
precision note: Recorded ESTABLISHED rather than DISPUTED. What is disputed is where Spar Lake is; what is established, and not in doubt, is that this row cannot be right about both of the things it says.

Evidence support: Derived from the cited evidence one source