Foremost Dual Rotary drills feature a unique lower rotary drive that is used to advance steel casing through unconsolidated overburden, such as sand, gravel, glacial till, and boulders. Pullback, pulldown, and rotational forces are effectively transmitted to the casing via high-strength steel jaws with carbide inserts.
An independent rotary top drive simultaneously handles a drill string equipped with a down-the-hole hammer, drag bit, or roller cone bit. Cuttings are typically evacuated with air, but Foremost DR drills can also be configured with pumps for mud or flooded reverse circulation drilling.
The top and lower drives feed independently, meaning that the bit position can vary relative to the bottom of the casing. Once the desired casing depth has been achieved, the DR continues drilling open-hole like a conventional top drive drill. With a Foremost DR drill, there is no need to trip out or change tools when transitioning to open-hole drilling.
Top 10 Reasons to Consider a Foremost Dual Rotary Drill
- Exceptional Overburden Performance – Foremost DR drills have been proven repeatedly in some of the toughest unconsolidated overburden formations, including sand, gravel, glacial till, and boulders.
- Open-Hole Versatility – The DR can be configured for a variety of drilling methods including mud, reverse circulation, and flooded reverse circulation.
- Straight Holes – The rotation of the casing by the lower drive results in a very straight hole making it ideal for shaft holes and foundation piles. This also minimizes stress on casing and casing welds, and eases the task of installing screens and pumps in water well applications.
- Basin Extraction – The lower drive is equally effective at pulling back casing; thereby simplifying the process of exposing a well screen or abandoning a well.
- Utilizes Conventional Tools – The drill string can be equipped with down-the-hole hammer, roller cone, or drag bit.
- Control of Discharge – Cuttings are diverted through the discharge swivel and can be directed to a safe and convenient dumping or monitoring point.
- Ease of Maintenance – Foremost DR rigs feature a directly connected hydraulic feed system which means no chains, sheaves, or sprockets to maintain. This type of feed system generates zero load on the mast crown, permitting a simple and lightweight mast design that does not sacrifice pullback capability.
- Reduced Operational Risk – The DR’s flexibility allows you to expand into new applications and gives you confidence to go into areas previously considered off-limits. You will know you have the right equipment to get the hole down the first time!
- Resale Value – There is arguably no drill on the market today that holds its value better than a Foremost DR. Dual Rotary owners tend to hold onto their rigs, making used inventory scarce, making for easy re-sale should the need arise.
- Foremost Technical Support – Foremost’s DR rigs are backed by the expertise and support of our product management team, field technicians, and one of the largest engineering departments in the industry.