Deposit

Murrin Murrin

A nickel-cobalt laterite in the Yilgarn Craton of Western Australia, which the USGS laterite model calls a classic clay-ore deposit of that class — and notes has no garnierite, which it attributes to a fully serpentinised protolith and poor drainage.

recognition basis: publishedDepositModel
realm: australia

What this record is, and who says so

Recognised on the basis of

Published deposit model

A deposit model publication that describes this body as a worked example of the class it defines.

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.

How it is interpreted

A deposit is not a mineral system. A source interprets it as an example of one, and interpretations change while the rock does not.

Interpreted as an example of Nickel-cobalt laterite system
By — USGS SIR 2010–5070–H, which calls Murrin Murrin a classic clay-ore deposit of the class.
The interpretation belongs to the source named in the model qualifier, not to the deposit. Another author may classify this body differently, and the record holds the interpretation rather than replacing the object with it.

Commodities documented here

Cobalt (commodity)documented association
The source documents the commodity in this deposit and states no economic role. Lithoen records the association and infers nothing about how it would be worked.
Nickel (commodity)documented association
The source documents the commodity in this deposit and states no economic role. Lithoen records the 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.

304 Mt

Reported reserve

effective January 2001, as the report states.

An ore reserve as formally reported, embedding modifying factors. Requires framework, category and effective date.

Ore reserves at Murrin Murrin were estimated at 304 million tonnes, at a cut-off grade of 0.8 percent nickel, as of January 2001. The figure is the report’s citation of the Register of Australian Mining 2001/02, not an estimate the report made.

0.064 wt%m Cobalt

Reserve grade

effective January 2001, as the report states.

A grade reported inside a formal ore-reserve estimate, which additionally embeds modifying factors — mining, processing, economic, legal.

The reserve grade for cobalt at Murrin Murrin was estimated at 0.064 weight percent as of January 2001, over 304 million tonnes at a 0.8 percent nickel cut-off. The figure is the report’s citation of the Register of Australian Mining 2001/02.

1 wt%m Nickel

Reserve grade

effective January 2001, as the report states.

A grade reported inside a formal ore-reserve estimate, which additionally embeds modifying factors — mining, processing, economic, legal.

The reserve grade for nickel at Murrin Murrin was estimated at 1.0 weight percent as of January 2001, over 304 million tonnes at a 0.8 percent nickel cut-off. The figure is the report’s citation of the Register of Australian Mining 2001/02.

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.

Ni-Co laterite deposits of the world (USGS OFR 2011-1058), record 8
Named there
Murrin Murrin
The source calls it
deposit
Lithoen reads it as
deposit (stated)
Murrin Murrin entered this corpus from the USGS laterite deposit MODEL, which names it as an example, and no mapping to the laterite compilation row was ever made — so the compilation's own statement that this row merges "Murrin Murrin North, Murrin Murrin South" never reached the corpus. The mapping is added to carry it. No point is emitted: the deposit already has a preferred position from a CRC LEME regolith report, and that report describes the same two areas independently, which is why the merge matters.
Merged into this row by the compilers: Murrin Murrin North, Murrin Murrin South. Those names were combined under the dataset’s own two-kilometre rule before Lithoen read it.
Read and refused
- grade columns with a value of zero — In both USGS deposit databases a grade of zero means the value was unavailable, not that the grade is zero. Reading it as a measurement would publish a false number.
- decimal-degree columns beyond the authored precision — The decimal-degree columns carry floating-point residue from the degrees-minutes-seconds columns that were actually authored. The point is emitted at the authored precision instead.

How this is mapped

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

Representative point
Point · 1 positionspreferred for publication
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 Murrin Murrin, from the coordinate printed in a CRC LEME regolith report. It marks the deposit area to the nearest arc-minute, about 1.85 km. It is not a boundary, not a pit, and it does not distinguish the two outcrop areas the same report describes.
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
establishedThe status of the geometry, which need not match the status of what the entity’s claims assert.
Source scale
1:250000
Stated positional accuracy
±1,852 m
What was done to this geometry
- By Lithoen — The report writes 28°50’S and 121°54’E, degrees and minutes with no seconds. Converted to decimal degrees and stored to four places. One arc-minute is about 1,852 m and that figure is recorded as the positional accuracy, so the stored decimals are not mistaken for precision the report never had.

How this record is known

1
Directly recorded: Observed or measured, reported by the party that made the observation.; 10
Settled consensus: Cited as the accepted position of the discipline.; 2
Interpretation: Reached by reasoning from evidence, or produced by a named model.

13 of 13 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.

EstablishedMineral norms from 495 pulp samples, phases identified by XRD and reflectance IR; elements by XRF, detection limits 10 ppm (Ni, Co, Cr) and 20 ppm (Mn)

Reported for this deposit

The mineral abundances the report gives were calculated as mineral norms from 495 pulp samples, after phase identification by X-ray diffraction and reflectance infrared analysis. Its elemental figures for nickel, cobalt, manganese and chromium were obtained by X-ray fluorescence, with detection limits of 10 parts per million for nickel, cobalt and chromium and 20 parts per million for manganese.

method: As stated by the report. The details of the norm calculation are said to be in Wells and Butt (2000), which Lithoen has not retrieved, so the method is named here and not described.
assertion basis: SOURCE_REPORTED