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Core Catcher Procedure
Removing the core catcher material is generally done by a designated technician. Every core recovered has a core catcher at the bottom of the core barrel. The core catcher is removed on the rig floor and passed to the designated technician. The technician must extrude all core material from the core catcher and placed in a core liner (guidelines and rules listed below). That 'Section' of core is called the CC (core catcher).
Below are a series of steps to help guide you through the Core Catcher (CC) procedure.

  1. Ensure the core catcher bench is clean before processing the next core catcher.
  2. Receive the core catcher from the rig floor.
  3. Extrude the inserts and core material from the core catcher shoe (Figure 1). Different tools and procedures are used for the APC, XCB and RCB core catchers. Learn these techniques from an experienced technician. The Core Technician on the rig floor can also provide insight into how the core catcher is put together and proper ways to extrude core so not to damage the core catcher shoe. Removing the core from the core catcher can become more difficult as depth of hole increases. When the core material becomes too difficult to remove manually, utilize the Arbor Press (instruction below).
  4. Maintain orientation and order of all material extruded from the catcher. Draw an up arrow on the trays you use to help remember your up direction. For hard rock mark the bottom of each piece with red or blue wax pencil.
  5. Place the core catcher hardware in a bucket for the drill crew to retrieve (after all material is removed).
  6. Once all material is extruded and in order, remove the bottom 5 cm of the material and give to the paleontologist. This is the PAL sample. A PAL sample is taken routinely from every core catcher. The typical length of a PAL sample is 5cm, however, the length of the sample may change if more or less material is required. Check with the Curator to make sure changes are allowed. (Figure 2). Note that for hard rock expeditions (RCB shoes) no PAL sample is taken.
  7. If the length of the core catcher material is less than 8 cm, check with the Curator if all material can be given to the PAL sample; this is called "All to PAL" and should be labeled as such on the D-tube label. By convention, the CC "All to PAL" label is attached to the D-tube containing the last sample.
  8. Select an empty piece of core liner that is longer than the material you have. Ensure that the liner is clean inside. Stuff the material into the liner with as little disturbance as possible. Push all material up to the top of the liner.
  9. Using the ruler, measure the length of the PAL sample from the bottom of the material you have then make a mark on the liner. This will be the total length of the core catcher representing the material taken for the PAL and the material left over. Place the liner in the chain vice and cut off the excess liner. (Figure 3). Any excess space should only be as long as the PAL sample.

Exception: In some circumstances, the PAL sample will need to be taken somewhere other than the bottom of the CC. This may happen with XCB cores where the material in the shoe is too disturbed to be useable. In this case you will need to make note of where the sample is located and give the offsets to the Curator/ALO. In red pen, mark the outside of the liner with the PAL location and offsets. When the CC is split in the lab a stryofoam spacer will be added to the correct interval.

  1. Affix the endcaps on the liner with acetone. It is important to ensure all sampling on the catwalk has been completed before doing so.
  2. After you have finished processing the CC, measure the length of the final core catcher on the ruler. Give the total length of the core catcher and length of the PAL sample to the Curator or ALO. It is important that this is an accurate measurement!


Example: For a CC that is 15 cm total length with a 5 cm PAL sample say, "Fifteen with five to PAL" or "Fifteen and five to PAL."

  1. Clean the CC section before handing it off to the core lab. Clean the core catcher bench and tools. Be sure to keep the bench stocked with usable core liner. If running low cut new pieces and stock on shelf below CC bench.


PPE: Hardhat, safety glasses, gloves (work gloves may be preferred because there may be sharp bits on the outer shoe), hearing protection. Optional: apron or rain coat.
Fig. 1: Extruding core catcher material at the core catcher bench. Notice the Paleontologist waiting with white bowl – give PAL sample to paleontologist.






(star) Or whatever the length of the PAL sample is.BottomFig. 2: Core Catcher Assembly

Top5cm*
PAL
Sample











Fig. 3: Core catcher material in Core Liner.
5cm*Empty
Liner











Total Length of Core Catcher


Arbor Press
If the Core Catcher material is difficult to manually push out from the core catcher use the Arbor Press (see Figures 4 and 5). There are two different jigs that can be used to assist with the pushing. One for APC (Figure 6) and one for XCB (one for lower bit; figures 7). Lubricate the moving parts of the arbor press with Lubriplate, or a mixture of Lubriplate and Marvel Mystery Oil.

Fig. 4: Arbor Press.
Hand crank, pull down to lower the ram into the CC shoe. BTMTOPRam/pusherPlace Core Liner here – mark core liner with 'way up' arrow to insure orientation. In this case the arrow would be down.CC shoe – place so that bottom is up and the ram pushes from bottom to top.Turn handle to bring ram to top of CC shoe.












Fig. 5: Metal disc for pushing on core material.
Use this between ram and CC material.

Fig. 6: APC Jig.






Fig. 7: XCB bit jig.

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