Core Goniometer - IM006-Revision2

The Pajari Core Goniometer is made of non-magnetic materials so that accurate compass measurements can be made on the core without concern for magnetically induced errors.

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Introduction

The Pajari Core Goniometer is designed to hold the core firmly and conveniently as the procedures to restore the core to its original orientation in the earth are carried out. Measurements obtained from one or more "in-hole surveying instruments" are used for this operation.
Once these procedures have been completed, the bedding planes or other planar and linear elements can be measured with a geological compass/inclinometer. The orientation and measurement procedures should reflect the accuracy required from the data. In the hands of an experienced Field Person, normal field procedures of "sighting" the attitude of the plane using a Brunton® Pocket Transit or Silva® geologist's compass can give accuracies of ±5° or less. If greater accuracy, or more consistent results from less experienced personnel are needed, techniques using the Scriber and Strike-line Caliper can be made with a minimal investment in increased processing time. Establishing appropriate setting-up and measuring procedures is time well spent.


Figure 1 - Basic Terminology of the Core Goniometer

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General Concepts
Holding the core		Figure 1 identifies the basic components of the Pajari Core Goniometer. The Collet is a clamping device to hold the core. The Hand Grip is turned clockwise (looking into the collet) to close and tighten on the core. Until the facing direction of the core is set, the Grip should be tightened only to the point where the core is held snugly but can still be rotated in the Collet . The Strap Wrench can be used to secure the core once all the orientation operations are completed.
Inclination		Progressive downward movement of the Locking Lever tightens the Wheel movement until the Collet is locked in position. Using an inclinometer, this function is used to reproduce the inclination angle of the core as surveyed in the drill hole by an inclination recording instrument. The Locking Lever should not be tightened beyond that which is required to hold the core at the desired angle. Over tightening the Lever will just require extra effort to loosen it for the next core orientation as no harm can come to the equipment.
Azimuth-Direction		The surveyed magnetic heading (magnetic azimuth) at or near the end of the hole is used to orient the core held in the Collet to its original earthbound azimuth (direction). This is done by rotating the base of the Goniometer on a flat level surface until the surveyed azimuth is read on a compass placed against the brass Azimuth Plate. The magnetic heading (azimuth) obtained from most compass based borehole survey instruments is not corrected for declination (angle of departure from True North). Therefore, the compass used to define the core direction in the Goniometer must have declination set to zero under these conditions.
Core Facing Rotational Orientation		Once the azimuth and the inclination of the core are set in the Goniometer, the original rotational orientation can be restored from tool-facing survey readings giving the angle of the mark on the core relative to the plumb direction. The illustrations used in this manual show the use of the Pajari Core Rotation Scale with a dial arrangement for Microsync readings obtained from Clay Impression Surveys. Other dial arrangements are available.
Ready for Measurement		The planar and linear fabric in the core can now be measured using standard geological practices with a suitable field compass/inclinometer. The core is now exactly in the same orientation relative to magnetic north and the gravitational field that it was before being broken off in the core barrel.

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Goniometer Instructions
Setting Up The Core in the Goniometer Place the Pajari Goniometer on a level surface. Make sure that there are no steel objects in the immediate environment that could affect the compass. If the Scriber Stand is to be used, provide at least 40 cm (16 inches) of clear space around the Goniometer. A half sheet of 13 mm (1/2 inch) plywood makes an ideal working surface. A Core Socket Sleeve may be required to bring the core to the size of the Collet. In Figure 2, the Sleeve is shown on the Core before insertion into the Collet. Alternately it can be placed in the Socket before core insertion. With the Collet fixed at an upward angle, unthread the Hand Grip so that the Collet is open to its maximum diameter. Place the Core into the Collet and tighten the Locking Lever just enough to support the Core without sagging by its own weight. Tighten the Hand Grip so the core is held snugly, but still capable of being turned. Using an inclinometer, adjust the angle until the angle matches the in-hole survey readings (Figure 3). Once the inclination angle is set, tighten the Locking Lever. Place the Compass against the Azimuth Plate and turn the Base until the Compass is at the surveyed magnetic azimuth (Figure 4).

Figure 2		Figure 3

Figure 4		The Core is now at its original earthbound inclination and azimuth.

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Turning The Core To Its Original Rotational Attitude


The Pajari Core Rotation Scale consists of two elements. The Index Sleeve has a line on the front face that continues onto the cylindrical surface. It is shown in Figure 5 as the first object on the core. The Rotation Scale , behind the Sleeve in Figure 5, has a *Dial‡* on the front face. Both elements have Thumb screws that are used to fix them in place once their positions have been set. The Index Sleeve is rotated so that its index line is coincident with the surveyed line marked on the core as depicted in Figure 5. The Thumb Screws are tightened to secure the Sleeve in place. The Rotation Scale is pulled snugly behind the Sleeve. It is turned until the Microsync facing degree reading from the in-hole Core Orientation Survey is coincident with the number on the Dial. Lock the Scale in place with the Thumb Screws. With both the Sleeve and Scale firmly fixed in place, rotate the Core in the Collet until the Level Bubble on the Rotation Scale is perfectly horizontal ( Figures 7 and 8). The Core is now completely in its original orientation.



‡The arrangement of readings on the Dial depends on the instrument that is used to survey the facing direction (rotational orientation) of the core. The Dial shown in Figures 5 to 7 is arranged for Microsync surveys using the Pajari Clay Impression Application.

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Measurements on the Orientated Core
Concepts The Pajari Core Goniometer was designed to hold the core in its original orientation while compass/inclinometer measurements of the bedding and other geological features can be made efficiently to the accuracy required. The Goniometer and the accessories are made of completely non-magnetic materials to avoid compass reading errors. Not even slightly magnetic decorative plating has been used. If modifications to the Goniometer or accessories are made, check whether the materials used attract the needle in the compass being used. Needless to say, the compass measurement should not be made in the Drill Shack nor next to a steel filing cabinet.
The Measurements Figure 9 shows a horizontal line drawn across a vein with a "marker" held in the Socket on the Scriber Bar. A similar line is drawn on the opposite side of the core with the Scriber Bar at the same height. The line joining the two intersections of the horizontal with the vein is the strikeline. The azimuth of the strikeline is the strike of the plane being measured. Alternately, a pointer may be used in the Scriber Bar and the intersection point marked by hand as shown in Figure 10. The latter method is capable of rapid marking. (See also Technical Note TN002)
		Figure 11 shows a Strike Line Caliper inserted into the Scriber Bar Socket after the intersections have been marked (without changing the height ). When the Points of the Caliper are placed on the intersection marks on either side of the core, the Scriber Bar defines the strikeline. The body of the Caliper can be rotated to be coincident with the surface trace of the vein, thus defining the dip when viewed along the axis of the Scriber Bar. See Also: Technical Note TN002; “Strikeline Caliper In Measuring Fabric Elements in Cored Rock”.

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Abbreviated Catalogue ‡

Catalogue numbers for CORE SIZE KIT, with GEOLOGISTS Model 1 GONIOMETER

Core Size	Core Size Kit	CORE SIZE KIT CONTAINS ALL THE ELEMENTS BELOW
Core Size	Core Size Kit	GONIOMETER KIT	COLLET	COLLET SLEEVE	CALIPER	ROTATION SCALE	INDEX SLEEVE
AQTK	3.01.010	GONIOMETER Geologists Model 1 KIT 3.02.100 Contains: Goniometer 3.03.001 Scriber Unit 1 3.03.002 Case Kit** 3.03.003	A Core Collet 3.03.014	None	A Caliper 3.03.046	A/B Rotation Scale 3.03.100 Clockwise Counterclockwise Special	AQTK/ATW 3.04.153

ATW	3.01.011			Special			AQTK/ATW 3.04.153

AQ	3.01.112			AQ 3.04.018			AQ 3.04.152

BQTK	3.01.115		B Core Collet 3.03.015 BTW 3.04.022	None	B Caliper 3.03.047		BQTK 3.04.156

BQ3	3.01.116			BQ3 3.04.020			BQ3 3.04.154

BQ	3.01.117			BQ 3.04.021			BQ 3.04.155

BTW	3.01.118			Bore OD of BQ Collet			BTW 3.04.157

NQ2	3.01.125		N Core Collet 3.03.017	None		N/H Rotation Scale 3.03.102 Clockwise Counterclockwise Special	NQ2 3.04.167

NQ	3.01.126			NQ 3.04.022			NQ 3.04.168

NQ3	3.01.127			NQ3 3.04.023			NQ3 3.04.166

HQ	3.01.130		H Core Collet 3.03.018	None	C Caliper 3.03.048		HQ 3.04.171

NTW	3.01.131			NTW 3.04.024			NTW 3.04.169

HQ3	3.01.133			HQ3 3.04.025			HQ3 3.04.170

NQ2 (H)	3.01.134			NQ(H) 3.04.026			NQ 3.04.168


Case Kit 3.03.003 contains:**
8.01.003	Staedtler Pigment marker
8.01.004	Pentel White Marker
8.01.005	Pencil - Dixon Primary marker
8.01.006	Pencil sharpener
8.02.003	Strap Wrench

‡ For core sizes larger than H, alterations or additions to the standard catalogue items, contact Technical Services at Pajari Instruments Ltd.

*Strike Line Calipers cannot be used for planar or linear elements which have a strike line at small angles to the axis of the core. Alternate methods have to be used and are outlined in Technical Note IN003. The larger the diameter of the caliper, the smaller this angle will be.

*The default Dial on the Rotation Scale is for facing readings obtained from the Clay Impression Core Orientation Application using a Pajari Microsync instrument. Other dials are available with different arrangements of indices and numbers to suit other core orientation applications. Request Technical NoteTN006 or call Technical Services.

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The Elements of the Pajari Core Goniometer

	1– Core Collet– Detachable and available in A, B and N sizes– The collet is made to the largest size in the series– Core Sleeves (not shown) are used to increase the diameter of the smaller sizes in the series. 2– Scriber Stand with Scriber Clamp attached. 3– Core Rotation Scale for restoring the original rotational orientation of the core from tool facing instrument readings. 4– Markers and Pens that fit a Socket on 7, the horizontal Scriber Bar. 5– A Thumb-nut and Washer is used to hold the Goniometer in place during transport. The Goniometer is oriented in the photo so that the center of gravity is most central in the Case. 6– Strike Line Caliper that is held by the Socket on 7. 7– The Scriber Bar fits into the Clamp on 2, the Scriber Stand, and holds the Markers or Strike Line Caliper as needed. The Socket for these accessories is at the left end in the photo. 8– The Strap Wrench is for tightening the Hand Grip on the Collet to secure the Core once all orientation procedures have been completed.
IM006-Revision 2,		©Pajari Instruments Ltd. 1998, 2000,

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