Reverse Circulation

The mineral exploration industry utilizes reverse circulation drilling to economically collect representative samples when searching for ore bodies to develop. The reverse circulation method is used predominantly in tough, broken, and abrasive formations. This method offers several economic advantages over diamond coring in these environments as well.

Matrix Drilling Products is the recognized industry leader in RC Drilling Tools. Matrix RC tools are distinguished by their superior performance, reliability, and durability. We manufacture a complete line of reverse circulation drilling tools and support the range with a comprehensive array of associated purpose specific accessories including – Interchanges- Rock Bit Adaptors – Subs – Back Reamers – Hoisting/ Lowering – Drill Collars – Swivels – Fishing Tools and much more.

We address the underground RC drilling operations with our M3.25 RC Drill Rod. Surface mineral exploration applications utilize our M4 – 4.5” – 5.5” – 6” RC Drill Rod while additional larger diameter RC Drill Rods 7″ – 9 5/8″ – 10.75″ are used for bulk sampling, mine dewatering, and water resource applications.

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Matrix Reverse Circulation Dual Tube Drill Rod – Underground

Matrix manufactures its 3.25 inch OD RC Drill Rod specifically for underground mining exploration applications. The M3.25 rod has distinguished itself, like its big brothers, as a very tough and durable product. Recently, Matrix has optimized the design of our M3.25 drill rod assembly for maximum airflow with the use of CFD (Computational Fluid Dynamics) modeling, thus increasing both productivity and depth capacity of this product.

Matrix Reverse Circulation Dual Tube Drill Rod – Surface

Matrix’s signature product line. Matrix’s dual tube drill rods feature a wide range of standard and custom sizes making our product adaptable to nearly any rig or drilling program. Rod sizing includes M4, 4.5”, 5.5”, and 6” OD.

Field-Replaceable Inner Tube (F.R.I.T.) RC Drill Rod

These dual tube products feature a removable inner tube, allowing customers to replace them on the job site without the need for machining or welding. This product line is very popular with our international customers.

Reverse Circulation Pre-Collar Casing

Matrix manufacturers Pre-collar Casing for reverse circulation applications. This casing must be stout with a durable thread profile to work with the larger RC rigs. We offer a choice of field proven thread profiles as well as both one-piece threaded casing and casing with composite alloy tool joints for extended wear life. We manufacture a full range of sizes and a selection of mid body steel, grade, and dimension.

Non-Magnetic Dual Tube

Matrix offers a non-magnetic RC dual tube product line machined from 304L stainless steel which is corrosion resistant against all types of mud. This product is typically used with sensitive surveying equipment.

Side Discharge Swivels

A Matrix specialty product. Allows drillers with smaller rigs to be able to drill with larger sized Matrix dual tube rods by discharging the cuttings below the top head. Features replaceable chrome wear rings for easy maintenance.

Side Entry Swivels

Placed below the top head, this product directs compressed air into the annular area of the Matrix dual tube rods while allowing a continuous discharge of cuttings through the top head of the rig.

Transition Rods

The Transition Rod effectively absorbs drill string torsional and lateral stresses associated with deep hole RC drilling. The redistribution of stresses will increase drill string life and minimize failures making the Transition Rod a prudent addition to your drill string. The Transition Rod is positioned strategically between the Drill Collars and the Dual Tube Drill Rod. Matrix Transition rods are machined from high grade alloy steel. Adaptable to any combination of drill collar and RC drill rod sizing.

Shrouded Rock Bits

Matrix offers a full range of shrouded Tricone bits providing top end protection to the Tricone bit body while maintaining a constant annulus. Our shrouds are designed to release the compressed air into the borehole close to the face of the bit for the most efficient clearing of cuttings.

Inner Tube Testers

Similar to a thread protector with a hole in it, Matrix Inner Tube Testers screw into the pin end of the RC Drill Rod. Then, by running compressed air into the opposite end of the rod a leak will be revealed if there is air exiting out of the hole in the tester lid. If a leak is discovered replacement of O-rings often fixes the problem. If the leak persists, it can be concluded that the inner tube has been ruptured and it will have to be replaced or scrapped.

Drill Collars

Matrix Drill Collars are used to achieve the correct weight on bit (WOB) to maximize penetration rates and prevent drilling in compression. Matrix Drill Collars are machined from high grade alloy steel corresponding to AISI 4145. Each collar undergoes rigorous quality control procedures during manufacture. Matrix offers a DI-22 thread form and a stress relief groove in the pin tool joint connection. By running Matrix Drill Collars, failures in the drill string will be reduced to a minimum resulting in less cost per foot for the driller.

Subs and Accessories


Stabilizers are used to assist in providing smooth, supported rotation of the drill string. Many times a formation may be subject to significant erosion, causing the borehole wall to be unstable. Stabilizers help to support the lower end of the drill string. In addition to providing supported drill string rotation, stabilizers enhance production as they keep the drill string aligned with the drill bit. Matrix offers milled spiral stabilizers are available up to 48″ long and to 20″ OD. Straight blade stabilizers are available up to 72″ long and 20″ OD.

Rock Bit Adaptors

The Rock Bit Adaptor (RBA) is employed in RC drilling with a Tricone Rock Bit. The RBA connects directly to the Tricone Rock Bit and its purpose is to direct the cuttings into the inner tube of the RC drill string.

The Rock Bit Adaptor is an assembly made up of 4 components:

  1. RBA Outer Body
  2. RBA Inner Tube
  3. Wear Sleeve
  4. Bladder

Matrix offers size specific RBA connection options to the tricone bit.

Interchanges (Crossover Subs)

The Interchange is a 3 piece assembly consisting of an Interchange body, an inner tube, and a top sub. An Interchange is used in conjunction with an RC DTH hammer or Tricone Rock Bit. Its purpose is to direct the cuttings from the bit into the inner tube of the RC drill rod where they flow up the string and are discharged on surface. Jetted style interchanges bleed a controlled amount of compressed air into the return sample stream thus “jetting” the cuttings up the inner tube. The Interchange is positioned in the drill string directly above the DTH Hammer. Matrix interchanges are built tough and available in 1, 2, or 3 slot designs with or without “jetting” and are made to fit each Matrix RC tooling size.

Air Injector Subs

The Matrix Air Injector is used in dual tube flooded reverse applications to aerate the water column inside the inner tube initiating upward flow. The air injector is the main, high-flow site of aeration found near the bottom of the string.

Aerator Subs

The Aerator Sub, in conjunction with the air injector sub, is utilized in dual tube flooded reverse applications. This product assists in initiating lift of the water column in the inner tube to begin circulation in deep hole drilling applications. The Aerator Sub inner tube features two small angled passages that allow a calculated amount of compressed air to be released to the inner tube before reaching the bottom hole assembly.

Blow-Up Subs

The Blow-up Sub is positioned at the top of the drill string disconnected from the top drive. It is used to direct the airflow up the inner tube (through the head to the sample collection tube) to clear a blockage. Available for all sizes of Matrix RC tools.

Blow-Down Subs

The Matrix Blow-down Sub is used to clear blockages in the slots of the interchange, Rock Bit Adaptor, or dual tube drill rod inner tube. Connected at the top of the RC drill string, this product seals the annulus of the dual tube rod and channels the airflow down the RC inner tube. The Blow-down sub is comprised of two components – the Blow-down Sub inner tube and the outer body.

Back Reamers (Digout Subs)

The Matrix Back Reamer (Digout Sub) has multiple functions. First, it helps prevent premature wear to the RC DTH Hammer. The second function of the back reamer is to in fact “back ream” the borehole. This is necessary in the event the borehole wall is unstable and experiencing partial collapse and assists the driller in removing the drill string from a tight borehole. The Back Reamer is positioned between the RC DTH hammer and the first RC Drill Rod.  The back reamer consists of an outer body and an inner lift tube. When the inner lift tube of the Back Reamer shows signs of deterioration it can be easily replaced.

Saver Subs

Matrix RC Saver Subs are manufactured from heat treated alloy steel and have exceptional strength and durability. The Saver Sub has an inner tube and an outer body. It is used to connect the swivel or Top Head Adaptor to the first RC drill rod. The saver sub becomes the main makeup and breakout connection, protecting the threads on the swivel or top head.

Lowering, Hoisting, & Handling

Matrix manufacturers hoisting plugs equipped with heavy duty bails to allow you to safely hoist and lower your RC drill string. 


This rod handling tool is very popular in angular hole applications. The Matrix Clamshell locks around the drill rod tool joints and assists in the angular positioning of the RC rod.  Whether you are adding or removing rod from the drill string, it saves time and makes the task easier.

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  • “Laibe / Versa-Drill customers buy our drill rigs for the quality and reliability so it was important for us to find a tooling manufacturer that followed that same standard and why we choose to offer Matrix products.”

    Marcus LaibePresident of Laibe Corporation / Versa-Drill