ttm005 resolve logging chip samples training module v2.0

7/31/2019 TTM005 Resolve Logging Chip Samples Training Module v2.0

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Copyright 2006, All Rights Reserved by Resolve Geo Pty. Ltd (www.resolve-geo.com)

Document No: TTM005

Release Date:

Version No: 02

Authorised By:

Technical Training Module: Logging Chips

1. Purpose and Scope

The purpose of this module is to provide training in logging chip samples. This module

forms part of the resource/training material designed to ensure a professional level of

competence in all aspects of these tasks.

This procedure is applicable to geologists who are required to log chips.

2. Task References

Resolve Safety Manual; Policies, JSAs, Work instructions

Work Instruction: W1006 Logging Chip Samples

Job Safety Analysis: JSA006 Logging Chip Samples

RA001 Risk Analysis

SP012 Personal Protective Equipment

SP024 Personal Protective Equipment

SPO27 Noise

SPO28 Dust

BM Alliance Business Improvement and Optimisation Geological Services

Document No. CQO-P-DBM-001 (P-EFO-010) Drill hole data collection, datamanagement and validation using Logcheck.

Work Instruction:CQO-WI-001 Field Data Logging Procedure (under review06/4/2005)

3. Definitions

3.1 Pedogenic

Pedogenic means pertaining to processes that add, transfer, transform, or remove soilconstituents.

4. Materials Required

This section outlines activity specific equipment required for the Geologist to correctly

log chip samples in the field. Equipment includes;

A sieve,

A water bucket

A hand lens,

Multiple field lithology sheets specific to your project,

A geological field logging dictionary specific to your project,

Pliers or LeathermanTM.

This document is considered controlled for 24 hours from 12/12/06 13:48

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For further specifications on required equipment, please refer to the table below.

Sieve

The sieve is used in conjunction with a water bucket to wash chip samples for analysis

and logging. It serves to separate the finer material, which passes through the sieve andinto the water bucket, from the coarse chips, leaving the latter visible for logging.

It is important to check your sieves condition regularly. Sieves commonly break at the

rim, which causes discriminate loss of sample (less dense material tends to disappear into

the water bucket, creating a bias in the material that is logged).An ordinary kitchen sieve is more than adequate for washing chips. It can be an

advantage to carry a spare in your kit. This will minimize the chance of poor logging in

the field if your sieve breaks.

Water Bucket

A reasonable water bucket is any deep container/ bucket that carries a water depthallowing the user to ergonomically agitate their sieve in the water to remove fine clays

(important factors include the diameter and depth of your chosen sieve to that of your

chosen bucket).The bucket fabric must also be robust and ideally UV resistant to some degree, as it will

be used in direct sunlight and will get physically abused over time.

Other factors to take into account include the total weight of the bucket when full ofwater (i.e. whether you are comfortable to carry a full bucket from the water truck to the

chips and along the length of the chips multiple times). A bucket can be cut down lowerto carry less water for those individuals who cannot comfortably carry a full bucket.

In the above diagram, A. shows 2 different types of bucket that can be used for logging

chips. The left example was a drillers mud container, which has been altered for use as

a chip logging bucket. The right example is a common plastic household bucket. Notethat the latter does not last long in the field, thus is not particularly dependable, as shown


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in figure B, where the base is cracked.

A third example of bucket, which is recommended above all of the examples, is a round

drillers Hi-Pol bucket, which has a re-sealable lid that will retain water during transport.This is particularly ideal for logging chips if you are logging after the rig has left the site.

Hand Lens

When choosing a hand lens, consider the diameter of the lens, the durability of the lens(remember, you are working in a hot, dusty and muddy environment), that there is not too

much distortion of the image at the edges of the lens, that the lens is protected and harddamage, and that your ey

toesight is good enough to effectively utilize the magnification

lers loupe is usually adequate,

s.

that you have chosen.

Typically, when logging chips, you will need to wear the hand lens around your neck all

day, so also ensure that it is not too heavy. A 10 x jewel

although many geologists prefer a 20x achromatic len

Lithological Field Logging Sheets or Tough Book

Ensure that you use those specific to your client.

Laminated Geological Services Field Logging Dictionary

Ensure that you use that specific to your client.Pliers, Leatherman or a reasonable and safe substitute of.

Defects can be inferred from chips, and a defect log can be created. Please contact th

relevant site or project ge

e

ologist to find out what your requirement is with respect toproducing a defect log.

sure that these samples are as accurate as

ossible, and contamination is minimised.

ll

and away from No-Go Zones, compressed air hoses and rod handling work

reas.

of

, or

, or safety related) factors to consider

hen observing an offsider sampling chips.

1) t the

designated chip area (shown in the image below). Occasionally offsiders may

5. Sampling Chips

The metre by metre samples that represent down-hole lithology are taken by one or both

drillers offsiders, dependent on the drilling speed and the enthusiasm of the offsiders in

question. As a geologist, it is important to en

pIdeally, ensure the chip samples are positioned so that you can observe the drilling

process whilst you are logging your chips and that you face the rig. This allows you to

react more quickly if there is an incident or the driller requires information from you.For the safety of the geologist, the chips should be located at least 8 metres from the dri

platform

a

Also, although it is important for you to focus on the job at hand, always remain aware

what is going on around you. For example, whether you have visitors to your site

there is any heavy machinery working in or around your work area (eg backhoe,bulldozer etc.). Also, remain aware of your proximity to the main access to your site.

There are 3 important scientific (not ergonomic

w

Encourage the driller to mark his/her pull down chains in metre lengths so tha

offsider has a visual prompt for when they need to deposit the chips into the


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: One chip sample representing a depth of 1 metre

: Direction of logging from the 1st sample (depth 1 metre)

3rdo

rdergroupof90m

2nd order group of 30m

1st order group of 6m

2nd order group of 30m

1st order group of 6m

3rdo

rdergroup

of90m

6. Steps for Logging Chip Samples

Before you commence logging chip samples, it is important to consider the positioning ofyour work area to the rig, and the environment (upwind of dust sources etc.)

It is also important to know the state of your equipment and the rig (safety clips on

compressed air hoses and fittings etc) to ensure your safety.

As illustrated below, chips need to be located 8 to10 metres away from the rig mast (thefall radius of a rod) and to minimise noise and dust exposure to the field geologist.

Distance of chips from rig 8 t10m

o

Offsider Sampling chips

Chips


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Note that the geologist can keepa better eye on the drilling stepand chip sampling if their chipsare placed out from behind therod trailer.

Drill Step

Chips

Rod TrailerDrill Rig

STEP 1 Fill up your water bucket.

If a rig is not on site at the time, the bucket can be filled by using a water container thatyou carry with you. If you choose to fill your bucket at the back of the rig whilst the rig

is operating, ensure (1) that you do this between rod changes (adding and removing rods)

and (2) that the bull hose is not pressurised. This will minimise your exposure to theserisks and any distraction to the offsiders and/or the driller whilst they are performing

hazardous tasks.

Preferably, ask a drillers offsider to fill the water bucket. This will remove this risk

from you.

Check the state of the water. It will need to be used to wash chip samples so should notbe carrying excessive fine sediments.

STEP 2 Collect chip samplePlace yourself at the shallowest sample depth. When starting from surface, this depth is

the first meter of sample (S1). Collect a good representation of this sample by scooping

your sieve through the sediment.

The image below is chips labeled with associated sample numbers. Samples areindicated by the prefix S followed by the sample number e.g.: S1 is Sample 1. Each

sample represents 1 vertical metre.

ChipsRod TrailerDrill Rig

When the chips are placedbehind the rod trailer, thegeologist is exposed to less rignoise, however cannot keep aneye on the drill step andsampling, because the rod trailerobstructs their view.


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STEP 3 Wash sampleThe size, shape and percentage of fines of your chip samples will vary dependent on how

they were drilled. Some factors to consider include (1) bit type (hammer, blade,

polycrystalline diamond bit (PCD)) and (2) fluid type (air, air and water, mud(chemically thickened water) or foam (commonly used when drilling loose sands)).

Samples will also vary dependent on rock type. When drilling through mudstone, orsandstones with a weak matrix, by the time the chips reach the top of the hole, they canbe so fine that they fall straight through the offsiders sieve, leaving either a poor

representation of the down-hole lithology or no sample at all. It is important to remember

that washing can occasionally bias your sample, if for example you are drilling a siltstone

and interbedded, weak-matrix sandstone.

Below is a picture showing the difference between shovel-lain, dry (left) and sieve-lain,

wet (right) chips. Note that on some rigs, the offsiders will wash the chip samples beforeplacing them out. This will facilitate your further removal of fines when you are logging

your chips. The above wet and dry samples have not been washed by the offsider, thus

contain high levels of fines or clays, which is what holds them together in a patty typestructure.

Dry Chips

For dry chips (those drilled solely on air), ensure that you agitate the sample to removeall dry fines before washing the sample. This helps to ensure that when you place the

sample in the water, your sieve does not clog up with clays. In the figure below, image A

shows the method of retrieving dry sample from a pile of chips. Image B shows theappearance of the sample after agitating the sieve to remove the fines.


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Chips should always be as clean as possible before washing them in water to minimize

the time spent trying to remove wet clay from the samples, your sieve and your bucket.

This is particularly important when dealing with highly weathered material, where thereis abundant clay, and very clay rich coal measures (for example, the Fort Cooper Coal

Measures, which are characterized by interbedded coal and tuff, with minor feldspathic,

medium-grained sandstones).

The below image shows A dry Chips taken from the weathered zone after agitating the

sieve and B the same sample after agitating in water, which washes the chips by

removing further dust fines. Note that in B, the 2 different lithologies can clearly beseen in the sample including coal (black) and 2 clays (1.light orange brown 2.light grey).

Wet Chips

For wet chips, you will not be able to move the fine clays and sands by agitation of the

sieve in the air. Letting them dry does not help, as the clay stays stuck to the chips.

These will need to be washed solely in the water bucket.

1) Place your sieve and sample in the water bucket so that the sieve remains horizontalin the bucket. This ensures no chips are lost in the bucket whilst cleaning thesample.

2) Gently agitate the sample in a circular motion. This encourages chips to roll aboutin the base of the sieve, and releases the fixed clays from the chips.

3) Check sample cleanliness by removing the sieve from the bucket and visuallyinspecting the chips. The chips are adequately clean once the majority of clays are

removed and you can see the chip composition in the sieve


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In the image below, A is a standard wet chip sample and B the same sample cleaned

inadequately. It can be hard to pick the lithologies due to clay contamination.

clean sample. Note the difference in colour, allowing simple visual lithologyidentification. Note also that this a

C is a

llows the geologist to observe the grain size and any

inor mineral contents.

s. When this happens, empty your bucket, wash it out and then refill it

with clean water.

7. LOGGING THE CHIPS

ges

ate petrology or more subtle

ness, it

ce of

pyrite, calcite and quartz can also indicate the presence of a fault or shear zone.

,rehole

m

Note that the water in your water bucket can become too contaminated with clays to

clean your sample

7.1 Why Log Chips when there are Geophysics Available?

Down-hole geophysical logging is used for the correlation of bulk lithological chan(for example the change from a fine siltstone to a coarser sandstone) as well as the

accurate positioning of coal seams, location of stone bands within seams and other

features, based on changes in gamma response, density and sonic velocity. These arerelated to differences in lithology, petrology, grain size and strength in some cases.

However geophysical logging does not conclusively indic

changes or minor occurrences of different mineralogies.For example, in the case of calcite veining, unless the vein is of considerable thick

will not be recorded in a geophysical log. Calcite veining is crucially important,

however, as it indicates faulting or abundant jointing, and therefore weaknesses in the

rock structure. Other examples of important occurrences include minor clays, sideriticbands and pyrite occurrences, the latter particularly within a coal seam. Abundan

7.2 Some General Principles for Logging ChipsWhen logging chips, it is important to remember that you are logging a mixed

representation of the down-hole geology. Thus you must use your geological knowledgeand knowledge of the local lithology to create a representational picture of the bo

stratigraphy. If contamination is present (as opposed to a combination of in-situ

lithologies), the source should be identified and the predominant, non-contaminantlithology logged as representative of that interval. Many important lithologies and


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cements are not identifiable from the geophysics. Hence, there is no alternative to

chip is smeared or obscured by the cutting action of the bit on the surface

f the chip. For this reason, always break a chip open (using fingers or pliers) to obtain a

unit

e

uld

ogies and at the correct depth. For further information seee Training Module titled Geophysical Interpretation and Correction of Field Data

a coal seam will support heavy machinery,roof and pillar weights, and in the case of an underground mine, (3) how the roof will

Sediments

nary. It has 13 Lithotypes to choose from. These can be defined

sing the U.S Standard sieve mesh particle size determination method. The below table

detailed logging of chip with respect to data accuracy and completeness.

Use your hand lens to determine grainsize and mineral composition. Often the texture orgrain size of a

ofresh surface.

Each sample represents 1 metre of stratigraphy. Therefore, dependent on bedding

thickness, the chips will often show numerous lithologies in a single metre sample.

Commonly, a single sample may contain sandstone, siltstone and claystone. These maybe logged as percentages using your knowledge and section 7.3.2 of this document.

However, the use of percentages should be avoided when describing a single facies

of interbedded lithologies which spans many metres. In this case, an attempt should bmade to log the more significant occurrences of a single lithology as single units.

Coal should also not be logged as a percentage lithology, when stone bands are also

present. A coal seam in chips should be logged as coal only and the stone contentsdescribed in the qualifiers. When geophysically correcting claystone and siltstone bands

within coal, over a specified thickness (normally a minimum of 10cm thick), they sho

be inserted as separate litholth

using Geophysical Logs.

Rock strength estimation is important to both open cut and underground miningoperations and affects (1) how easy it will be to remove overburden and interburden to

access coal seams, (2) whether the floor below

react to the removal of coal from beneath it.

7.3 Logging Unconsolidated

7.3.1 Choosing a Lithotype

You will need to choose a lithotype based on the options provided in the field logging

dictionary as specified by your client.A good general dictionary (which is currently most commonly used by Resolve) is the

BMA Geological Dictio

uoutlines each of these:

Well Sorted Material

Soil

Any definition of what soil is can be disputed, however the definition used here is of a

pedological nature1 ; An arrangement of natural mineral and organic materials formed at

ear-surface alteration and translocation processes through time.the surface of the earth from originally geological and biological materials by surface andn

1 The Edaphological definition would be Soil is the natural medium for the growth of land plants"


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Typically, soil is a dark brown in colour, and contains abundant organic material.

Clay

Any grain size between 0.00006mm and 0.0038mm.It is difficult to visually distinguish silt from clay, and both will fall through your sieve

Instead, ensure that the rock or sediment is free from driller contaminants and place asmall sample of the mate

.

rial in your mouth. If it is clay, it will dissolve in your saliva

s (note that dental problems can develop from chewing

on rocks), clay will smear between your fingers, leaving a streak behind, whereas silt

tends to fall off when smeared.

and disappear. Silt, on the other hand, will be a little crunchy (i.e. you will be able to feel

it between your teeth).If you prefer not to chew on rock

Silt

Any grainsize between 0.0039 mm and 0.0624mm.Again, as an unconsolidated material, this will fall through your sieve. See description of

for how to distinguish clay from silt in the field (feel for the crunch).a clay

SandAny grain size between 0.0625 mm and 1.99mm.Sands will also need to be broken up into grainsize. See section 7.3.4.

It is OK to log a very fine sand as a silt and vice-versa, however ensure that if you come

d between your teeth, sand feels extremely abrasive and uncomfortable.

If possible, ensure that you log the composition of your sand in the qualifiers (Section7.3.5).

across similar sediment, you log it in the same manner to ensure consistency.

If place


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Gravel

Gravel is any sediment with a grain size between greater than 2.00 mm.Gravel can be anything from a Granule (2.00 mm 3.99 mm) to a pebble (4.00 mm 15.99 mm) to a cobble (16.00 mm 255.99mm) to a boulder (>256mm).

It is therefore important to define any gravel that you see in your qualifiers (Section

7.3.5)

Mixed Lithologies

Clayey Sand

Any bulk material that is abundantly sand but has a clay fill. Note that when squeezed,

each cluster turns into fine sand, with minor clays. When rolled between the fingers, itremains friable.

Sandy Clay

Any bulk material that is abundantly clay but has a sandy element. When rolled between

the fingers, small cigar-shaped forms can be created, which do not fall apart like clayey


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sands.

Gravelly Sand

Loose material that is abundantly sand, but has a gravel element.

Clayey Gravel

Loose material that is abundantly gravel but has clay fill.

Sandy GravelLoose material that is abundantly gravel but has a sand fill. S

DURICRUSTS

Calcrete

An indurated surface formed by weathering processes involving cementation of the

surface soils and weathered rock by calcite (calcrete) (i.e. any cemented terrestrialcarbonate accumulation).


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It typically comes in the form of a moderately, strongly or very strongly cemented layer

which is either continuous, or if discontinuous or broken, consists of at least 90% of hard

(moderately cemented or stronger) calcrete fragments, most of which are greater than200mm in smallest dimension.

Unfortunately, it may vary significantly in morphology and degree of cementation.

Calcrete does not encompass the common soft segregations of finely divided carbonate,nor accumulations of pedogenic carbonate in the form of discrete nodules or concretions

(contrary to popular usage).

Calcrete in the tertiary horizon will appear as hard white or creamy chips.

Ferricrete


surface soils and weathered rock by iron oxides (ferricrete, sometimes known as laterite).Ferricretes a typically red or browny-red in colour.

Ferricrete in the tertiary horizon will appear as hard chips of opaque browny-red(orangey) glassy material. Ferruginous nodules are not ferricrete. These can be

mentioned in the qualifiers section of your log.

Silcrete


surface soils and weathered rock by silica (silcrete).

Generally found within the Tertiary units, it is also often found within older sedimentsproximally below the base Tertiary boundary.

Silcrete can range from silica-cemented sand and gravel to an amorphous matrix enriched

with small silica particles. A minimum silica (SiO2) content of 85% weight has beenproposed by Summerfield (1983)

2to distinguish silcretes from other duricrusts.

2 Summerfield, M.A. 1983a. Silcrete. In Chemical sediments and geomorphology, edited by A.S. Goudie

and K. Pye. San Diego: Academic Press, pp. 59-92


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Fill

Mined material (overburden etc.). You will specify this if you are drilling through a spoil

pile (or similar altered terrain) in order to access the unaltered rock beneath.

7.3.2 Estimating Percentage

When logging chips with multiple lithologies, it is sometimes beneficial to log using

percentage, in particular if you want to illustrate other important minor occurrences.

For Example, when logging a Siltstone with abundant sandstone, minor clay and rare

pyrite, it could be logged as:

Siltstone, medium grey, Abundant Sandstone, minor clay bands, rare pyrite.

However, using this definition and the associated number of qualifiers, many of them will

not get recognized once your data is processed.

Another way to log the same sample is by logging the dominant lithologies aspercentages, and then commenting on the minor lithology as a qualifier;

60% siltstone, medium grey, 40% fine-grained sandstone, light grey. Minor claybands, rare pyrite.

Again, this sample could also be logged as;

55% siltstone, medium grey, 35% fine-grained sandstone, 10% claystone, light

creamy brown. Rare pyrite

There is also no reason why you could not mention the pyrite in the minerals section, thusleaving room in the qualifiers to illustrate what the petrology of the sediment is (for

example; lithic and feldspathic grains). In some lithology dictionaries, the mineralogy

section is the only place where you can describe the minerals association to the parent

material.

The best approach is, as ever, to detail the actual occurrence of individual lithotypes in

the intervals in which they occur. This can be time consuming in thicker sequences withmultiple lithotypes, but best reflects the stratigraphy you are describing.

None of the examples shown above are the be all end all solution to logging chips witha combination of lithologies, however, the third example in particular increases the

chance that the information that is specified in the qualifiers is considered.

The chart below is taken from Terry,R.D.,Chillingar,G.V.,(1955), that can be used in the

field to determine what percentage of different lithologies are in your chip samples.


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2% 5% 10% 15% 30% 50%

1% 3% 7% 15% 25% 40%

7.3.3 Colouring

When logging the colour of a lithotype, you are not only specifying its primary colour but

also its shade and hue.Firstly, you will need to establish the shade of the chips. This defines either how light or

dark they are (3 options; Light, Medium or Dark) or if they are textured (textured

mottled, speckled, variegated). When logging colour, ensure that you maintain

consistency when logging. If you call something speckled on first sighting and it

reoccurs deeper in the hole, you must still call it speckled.

Secondly, you will need to define the hue of the chips. Each lithotype has a primarycolour, however sometimes; it also has a secondary colour. For example an unweathered

siltstone may be dark grey, but may tend to have a blackish hue, so its colour would be a

dark blackish grey.

Finally, you must log the primary or dominant colour of the lithotype.

When logging tertiary unconsolidated material, due to the weathering processes,

colouring isnt always easy to log. As a geologist, you are required to take an average of

colour.For example, if you wash sandy clay, that has a mixture of 20% dark ferruginous and

30% light silica grains, within a creamy clay matrix, it will have 2 very different and

distinct colours; however it is not speckled, mottled or variegated. Depending on the

percentage of grains of different colourings, this could be logged as:

Sandy Clay, Light reddish cream


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A more detailed description of the ferruginous and silica grains can then be specified inthe qualifiers (Section 7.3.5).

7.3.4 Grainsize

Grainsize is very important to record in unconsolidated sediments, as the lithotype maynot specify this.Options include those for sorted material, and those for unsorted material. Note that if

you log a clayey sand, the lithotype picks up the fact that there is clay. Therefore, log the

grainsize of the sand, and not the clay. The same applies to sandy clay.

Grainsize in gravels may be specified in the qualifiers section (See section 7.3.5), where

you will also be required to specify the composition of the gravels. However, it issometimes useful to assign a grain size which describes the range of grain or particle

sizes within the gravel, e.g. extremely coarse to very fine.

Size in mm SedimentaryRounded, subrounded,

subangular

Pyroclastic

Particle or

fragmentLithified

ProductFragment Lithified

Product

Boulder BoulderConglomerate


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7.3.5 Lithological Qualifiers

7.3.5.a) General

Specifying lithological qualifiers when logging chips ensures that petrological andmineralogical details are recorded within the lithology. In some lithological dictionaries

and applications, the number of qualifiers is limited, so firstly input the qualifiers that youbelieve to be the most important. Base your decisions on your clients specifications. Forexample, BMA only uses the first 3 qualifiers for modeling purposes, and Anglo will

only use the first 2.

This does not mean that any other qualifiers that you log are unimportant, in fact themore detail that a geologist can gather from a chip sample, the more useful the data will

be in the future.

Specifically, if you are logging a quartzose sand, which has a lateritic (ferruginous) band,

you would note that the sediment has ferruginous bands before noting that grains are

siliceous, or quartzose; as shown below. This is because the ferruginous band results in ahard layer that will affect overburden removal.

Sand. Light reddish cream. Medium Grained. Rare ferruginous bands. Siliceousgrains.

7.3.5.b) Logging the Grainsize of Gravel

The grainsize of gravel will affect ground removal. Therefore is important to recordgrainsize in your lithological log. It was previously noted that this cannot be recorded in

lithology. It can be recorded in the grain size field but it is best recorded in the qualifiers.

The benefit of having this detail here is that the composition of the gravel can be recorded

in association with the grainsize.There are 3 different gravel sizes, as shown in the diagram below. Note that each gravel

definition excludes the area of the smaller gravel definitions.

For example, when logging gravel made of 20% quartz and 80% ferruginous pebbles,

you may log this as;

Gravel. Medium ceramic orange. Ferruginous and quartz pebbles

You may also like to give an indication of the dominant type of pebble;


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Granule (2.00 - 3.99mm) Pebble (4.00 63.99mm) Cobble (64.00 255.99mm)


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Gravel. Medium creamish orange. Common ferruginous pebbles. Occasionalquartz pebbles

The latter does not give an exact idea of composition however it does indicate that the

sediment is more ferruginous than quartzose and is medium gravel (pebble).

7.3.6 Estimated Strength

The table below shows the different strength tests for unconsolidated material. This is

also available on your BMA Geological Services Field Logging Dictionary sheet.

Strength Test Guide

very soft Exudes between fingers when squeezed in hand

soft Can be moulded by light finger pressure

firm Can be moulded by strong finger pressure

stiff Can not be moulded by fingers, can be indented by thumbvery stiff Can be indented by thumb nail

hard Can be indented with difficulty with thumb nail

loose Falls apart easily

unconsolidated No material holding the sediments together (eg. Sand, gravel etc.)

7.3.7 Weathering

The level of weathering in different rock or sediment types is assessed by looking the

oxidation level of the material. This is indicated by colour change through the depthprofile. All unconsolidated material at the surface is extremely weathered, as it is the

unconsolidated top of the weathering profile. It is an acceptable practice to only indicate

weathering below the Tertiary (i.e. above the Tertiary, the weathering field can be left

blank), although some clients will require it. Weathering is discussed in further detail inSection 7.4.4.

7.3.8 Picking Base of Tertiary

In the more northerly regions of Resolves sphere of operations, the Base of Tertiary is

often where unconsolidated sediments unconformably lie atop consolidated Permian

rocks. But this is not always the case and occasionally the horizon is hard to pick. Inother areas, Triassic and/or Jurassic strata also occur. Thick lateritic weathering often

occurs at the top of the Permian sequence, and can extend for many metres down through

the Permian. It is important to log the Tertiary unconformity at the top of lateriticsequences. The top of the Permian is sometimes unconsolidated material, particularly in

flood plains or in highly reworked regions. A part of the logging process is to pick the

base of the Tertiary as accurately as possible. This can be difficult, as both may behighly rich in clays and have a sandy component.

Note that both the Tertiary and Permian can be unconsolidated. In some areas, Tertiary

tends to have a reddish colour, whereas the Permian is a more brownish or yellowish


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colour. This is illustrated in the image below. In other areas, the Permian has a micacomponent whereas the overlying units have none. Ensure that you ask your Project or

Supervising Geologist for the local indicators.

The Tertiary-PermianBoundary

7.4 Logging Consolidated Material

7.4.1 Introduction

This section looks specifically at what lithologies you may encounter when logging

consolidated material.

For details on estimating percentage and strength and details on colouring, grainsize,

lithological qualifiers and weathering, please refer to the relevant sections in Section 7.3.

7.4.2 The Common Lithologies that you will Encounter in our Region

When logging lithology for consolidated material, the grainsize is not important as it is

specified in the lithotype. For example, very fine grained sandstone is logged as an S1,which by definition is a very fine grained sandstone.The following are examples of the most common lithologies found in this region and

their properties. Note that the latter are not necessarily the properties of each lithology in

all areas.

7.4.2.a) Major Lithologies

Claystone (CY) (Tuffaceous)

Colour: Light or medium Brown or Grey, with an orange, or red hue. Sometimes

creamy. In the case of the three samples in CY1 below, the first is a creamy grey, the

second a grey brown and the third a brown-grey.Strength: Very low strength low strength

Grainsize: Not visibleto the naked eye.Claystone tends to absorb water and expand, thus will tend to be greasy between yourfingers (like soap) and leave a clayey streak behind (CY2).


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Other: Many claystones in this area were originally tuffs (volcanic ash deposits). The

tuffaceous origin of the claystone should be specified in the qualifiers. The examplebelow is a claystone within a coal seam.

Carbonaceous Claystone

Colour: Dark Brownish Black or Dark Greyish Black

Strength: Very low strength low strength

Grainsize: Not visibleto the naked eye. Identify in the same manner as claystone.


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Mudstone

Colour: Typically dark grey (C G), however they can also be medium or light grey,

depending on carbonate content and can have a brown hue if sideritic.

Strength: Low strength moderate strength. High strength if sideritic.

Grainsize: Not visible to the naked eye. A mudstone is typically a dirty siltstone, ie

one that has an abundant clay matrix.To check whethera chip sampleismudstone, if youplace a piece between your teeth, you will feel some very fine grains, but the sample will

tend to be clay dominated.

Siltstone (ST)

Colour: Typically medium grey (B G), however they can also be dark or light grey,

depending on carbonate content and can have a brown hue if sideritic.


Grainsize: Not visible to the naked eye. To check whethera chip sampleissilt or clay,

wet the sample and see whether a single chip feels slippery (soapy) between your fingers.

If not, it is probably silt. A second check is to place a tiny piece between your teeth, silt

grains are recognisable as grains, but are not particularly uncomfortable, sands are veryuncomfortable.

Some siltstones will have a clayey matrix (CL MA). Specify this in the qualifiers, oralternatively, rename as a mudstone.

In the below example, note that to the naked eye, no grain is visible in the siltstone,whereas there is a grainy texture in the sandstone.


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Carbonaceous Siltstone (XT)

Colour: Dark Brownish Black or Dark Greyish Black.

Strength: Low strength moderate strength.

Grainsize: Not visible to the naked eye. The same check applies as with a Siltstone.

Sandstone

Colour: Light to Dark Grey. Sometimes speckled. The sandstones in this region are

both lithic (containing detrital rock fragments), felsic (contain white calcium rich

feldspar) and in some cases are micaceous (muscovite). Common quartz grains may beseen, but rarely comprise more than 20% of the total grains.

The abundance of mica and organic material can be logged in the qualifiers as

carbonaceous and micaceous laminations (CS MI LM).


Very Fine Grained

For comparison between Very fine sandstone and Siltstone, see section above on

Siltstone.

Fine Grained


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Medium Grained

Coarse Grained


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Note that this sample has some carbonaceous blebs within the sandstone matrix.

Very Coarse Grained (Photo required)

Carbonaceous Sandstone

Colour: Dark Brownish Black or Dark Greyish Black.

Strength: Medium strengthSandstone with a rich carbonaceous component, which results in the darkening of the

rock.

(Photo and description required)

Coal

Colour: Typically black (K)

Strength: Very low strength low strength

Grainsize: Not applicable to this lithotype

Weathered Coal

Colour: Typically medium browny black to black (B B K K), however very weatheredcoal can be dominantly brown. Note that weathered coal has a brown streak when

rubbed in the hands.Strength: Very low strength low strength

Grainsize: Not applicable to this lithotype

Very weathered coal can appear sooty, and have a graphitic texture. Moderately

weathered or slightly weathered coal will often present as slightly coarser fragments thanfresh coal.

Note that this example of weathered coal (highly weathered) has abundant tuffaceousclays in it; the lighter material.

Coked Coal

Colour: Silvery or grey, rather than black.

Strength: Very low strength low strength. May be harder that normal coal.Coked coal typically looks vesiculated and shiny on a freshly broken surface. Often, itsdensity is higher than normal coal. It can be predicted from a geophysical log showing a

normal coal gamma response, but a higher than normal coal density response.

Occasionally, whitish intrusives (fresh or highly altered) can be seen intersecting the coal.

(Photo required)

Coal

Coal is very weak and black, the worst way to have your coffee. When coal appears in


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the chips, it typically occurs as a bubbly mass. Frequently, once washed, there are other

lithologies within a single chip sample of coal; in particular claystone and/or siltstone.

As previously specified, coal seams should not be logged as a percentage lithology. Clayand silt or sandstone bands will be extracted and depths specified using the geophysical

log (See the Training Module titled Geophysical Interpretation and Correction of Field

Data using Geophysical Logs).

Basalt

Colour: The basalt that you will find in our section of the Bowen Basin is typically green

or greenish grey in hue, and is crystalline.Strength: Moderate strength high strengthThe basalt that you will find in our section of the Bowen Basin is typically green or

greenish grey in hue, and is crystalline.

Felsic Intrusion

(Photo and description required)

7.4.2.b) Minor Lithologies (to be specified in qualifiers)

Sideritic (Contains Siderite (FeCO3))

Sideritic rock is a high strength rock and has a distinct brown colour. If you struggle tobreak a brown coloured siltstone or sandstone, the probability is that it is sideritic.


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Pyritic (Contains Pyrite (FeS2)

Pyrite is a brassy yellow in colour (thus reflects in the sun) and is a high strength rock. It

typically occurs within either coal bands or in sand or siltstones within siderite bands,

where there is iron available.

Calcite (CaCO3)

Calcite will typically occur as veins in joints. Calcite is a low strength rock. In this area,

it typically occurs as a pale cream, or yellow rock. Although it looks similar to quartz in

chips, it is a lot softer, and will break easily in your fingers.


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Quartz (SiO2)

Quartz veins have been known to occur around igneous intrusions, however quartz is

most commonly found in the unconsolidated sediments as gravel. Quartz in this area is

typically white to yellow (Citrine), and is a high strength rock. When placed between theteeth, quartz feels glassy. Do not try to chew on it or you may break your teeth.

7.4.3 Estimating Rock Strength

The table below shows the different strength tests for consolidated material. Note thatthe definition is based on a core sample and your ability to break large samples, which

cannot occur in chips. Use your logic, intuition and experience with core to assess the

estimated strength of each lithotype. Remember, it is strength estimation and it issubjective, so the most important factor is youre your results remain relative and

consistent throughout the hole. Again, please refer to your clients definition.

Strength Test Guide

Very low

strength

Scratches easily with thumbnail. Crumbles under sharp geopick blow.

Peels easily with knife. 1 blow of geopick.

50mm core x 150mm long breaks against a solid object with a singlegeopick blow.

7.4.4 Picking Base of Weathering

As mentioned in section 7.3.7, base of weathering is determined by looking at colour

change due to oxidation through the depth profile. By this method, what the geologist


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picks as the base of weathering is not the TRUE base of weathering, but the visual baseof weathering.

For example, when chipping for the purpose of determining the Limit of Oxidation

(LOX) within a coal seam, the visual base of weathering can be picked up to 6 metersabove the true base of weathering.

Weathering does not necessarily occur at a constant gradual rate from extremelyweathered to fresh, but can move both ways along the scale. For example, someconsolidated sediments, particularly coarser more felsic sediments, or fractured

lithologies (eg. igneous), can act to channel water and can hence be more oxidised than

sediments above and below them. This is particularly apparent in basalts.

The below table defines what visual changes you are looking for.

Extremely

Weathered.

Rock type does not in any way resemble its original form in texture,

colour, and composition.

Highly

Weathered.

Rock will have a brown colour, however is identifiable as a rock

type (e.g. Sandstone, siltstone, claystone etc.)Moderately

Weathered.

Rock will be its original colour; however will have a reddy, browney

or yellowey hue (discoloration).

Slightly

Weathered.

Rock will be its original colour; however will have minor weathered

grains (reddy, browney or yellowey specks of discoloration).

Fresh. There is no discoloration due to oxidation.

The boundary between Slightly Weathered and Fresh is the Base of Weathering.

7.5 Data Files that need to be Created for Chip Holes

Files that need to be created include;

Header,

Drilling,

Geology; and

Water flow files.

Ensure that you create these files.

On some sites, you will also be required to create a defect file from lithology and strengthchanges in chips.

ttm005 resolve logging chip samples training module v2.0

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