ACALA

Geological Expertise, Mining Excellence

Consulting · Mineral resource estimation

A resource statement your bank, your board, and your geologist can all sign.

ACALA’s geologists build independent mineral resource estimates from validated drill data, geostatistical modelling, and QAQC review, reported to JORC 2012, SAMREC, NI 43-101, SNI and KCMI. The result is a number you can raise money on, and a model you can plan a mine from.

Discuss your project on WhatsApp
Request a proposal
Experimental semivariogram with a fitted spherical model: nugget, sill and range sill · C0 + C = 1.00 nugget · C0 = 0.25 0lag h (m) γ(h) range a = 140 m
Spherical variogram fitted to nickel laterite assays. Drag the handle to see how the range changes the fit.
JORC 2012Australasian code, the one most lenders ask for.
SAMRECSouth African code, for dual-listed owners.
NI 43-101Canadian instrument for TSX-listed issuers.
SNI 4726:2019Indonesian national standard for resources and reserves.
KCMIIndonesian competent person code.
Feasibility inputsModels built to carry straight into scoping, PFS and FS.
ACALA geologists checking drill core in a core tray at the Sungai Mak drill site
From the rock face to a resource statement a regulator accepts. ACALA geologists logging drill core at the Sungai Mak exploration site.

What you receive

Not just a tonnage. A model, a classification, and the reasons behind both.

Every estimate leaves you with files your own team can open and defend: the block model, the domains, the variograms, and a report that shows how each number was reached.

A signed report page beside the three reporting codes it can be written to: JORC 2012, KCMI 2017 and SNI 4726-2019Competent PersonJORC 2012KCMI 2017SNI 4726-2019THE CODE YOU CHOOSEsigned, and in plain language

Independent resource report

Written for public reporting under the code you choose, with a competent or qualified person’s sign-off and a plain-language risk statement.

A block model shaded from measured through indicated to inferred, with two geological domain boundaries drawn across itDOMAINS OVER THE BLOCK MODELmeasuredindicatedinferreddomainboundariesdelivered asproject files

Block model and domains

GEOVIA Surpac block model with geological domains, estimation parameters, and classification, delivered with the project files, not just a PDF.

Plan view of a drill hole grid at eighty metre spacing, with four infill holes circled where they move the classification from inferred to indicated80 mPLAN VIEWinfill drilledwhere it movesthe categoryinferredindicatedspacing that classification can carry

Drill hole spacing analysis

Quantitative inputs for classification and for planning the next drilling campaign, so infill holes go where they change the category.

A quality control chart of certified standards against the expected value with eight per cent limits, one batch failing and circledstandard failedCERTIFIED STANDARDS, BATCH BY BATCH+8 %−8 %checked before anything is modelled

QAQC and data validation review

Assay reports, drilling methods, collar and downhole surveys checked before anything is modelled, with findings you can act on.

A list of the five estimation parameters, each ticked as reviewed: composite length, top cut, variogram model, block size and estimation methodcomposite length1.0 mtop cut12 g/tvariogramsphericalblock size25 × 25 × 5 mestimationordinary krigingEVERY PARAMETER REVIEWED AND EXPLAINEDreviewed, or set from scratch where none existed

Geostatistical parameter review

Composite length, top-cut strategy, variogram model, block size, and estimation method reviewed or set from scratch, and explained.

Several simulated realisations shaded as a band with the median highlighted, showing a range of outcomes rather than one numberMANY RUNS, NOT ONE ANSWERP90P50P10a range you can plan against, not a single point

Uncertainty and risk evaluation

Where the data warrants, simulation and local uniform conditioning to show the range of outcomes, not a single point.

How the work runs

Seven steps, in the order the geology demands.

Geology is carried through the whole chain. Every step reads from the one before it, and nothing is estimated until the data and the domains have earned it.

  1. 1

    Validate source data

    Laboratory assay reports, drilling methods, collar locations, and downhole survey methods are checked against originals.

  2. 2

    Assess QAQC

    Standards, blanks, and duplicates are evaluated; failures are traced to batches and their effect on the estimate is stated.

  3. 3

    Interpret domains

    Existing interpretations are reviewed or new ones built, including Geological Matrix Analysis, so estimation respects the geology.

  4. 4

    Exploratory data analysis

    Statistics by domain, boundary conditions, drill data type comparisons, and top-cut decisions, documented.

  5. 5

    Variographic analysis

    Spatial continuity and nugget effect characterised per domain and element; single and multi-element where it matters.

  6. 6

    Kriging neighbourhood analysis

    Search, block size, and sample counts tested so the estimate is neither over-smoothed nor noisy.

  7. 7

    Estimate and classify

    Global and local estimates with the most suitable linear or non-linear method, then classification supported by the spacing analysis.

Who does the work

Geostatisticians who also plan mines.

Our geology team holds postgraduate qualifications in geostatistics and works daily in GEOVIA Surpac and 3DEXPERIENCE. Because the same people design pits and schedules, the resource model is built to be mined, not just reported.

Meet the team · Clients and standards

Example

Drill hole spacing analysis for classification

Defined quantitative inputs for resource classification and for planning infill drilling, replacing a rule-of-thumb grid with one derived from the deposit’s own continuity.

Example

Domaining strategy tested by simulation

Built a geostatistically sensible domaining strategy for a specific lithological unit, then used simulation to evaluate the interpolation risk inside it before the estimate was accepted.

Other services

Where a resource estimate usually leads.

Reading

From our geologists

In the software

Estimation in Surpac.

Screens from the GEOVIA Surpac brochure: the block model the holes produce, and the search the variogram defines.

GEOVIA Surpac: block model coloured by grade with the drill holes that informed it

Block model and drillholes

The estimate, block by block, with the holes that made it.

GEOVIA Surpac: anisotropy search ellipsoid with its major, semi-major and minor axes over the grade surface

Search ellipsoid

Variography turned into a search oriented to the mineralisation.

Download: GEOVIA Surpac brochure (PDF, 2.5 MB)

Questions we get

Resource estimation FAQ

What data do you need to start?
Collar, survey, assay and lithology tables with the original laboratory certificates, the QAQC data (standards, blanks, duplicates), topography, and any existing interpretations or models. We tell you within a week what is missing and what it costs the classification.
Which reporting code should I use?
The one your audience reads: JORC 2012 for most lenders and ASX, NI 43-101 for TSX, SAMREC for JSE, and SNI or KCMI for Indonesian regulatory and IUP reporting. One estimate can be reported under more than one code; the work is the same, the disclosure differs.
How long does an estimate take?
For a single deposit with clean data, six to ten weeks from data receipt to signed report. Data problems, not modelling, are what extend it, which is why validation and QAQC come first.
Can our own geologists do this with your support instead?
Yes. Many clients licence GEOVIA Surpac through ACALA, take the resource estimation course on their own data, and have us review the parameters and sign off. See training and the academic programme for the options.

Next step

Send us the drill database. We will tell you what it can support.

A first review of your data and existing model is the fastest way to know whether you need a full estimate, a parameter review, or more drilling first.

Chat on WhatsApp
Request a proposal
Bekasi, Indonesia
+62 21 8066 9600
office@acala.co.id
WhatsApp