PROSPECTING The rig is shown being used to determine the volume of overburden that will need to be removed prior to open cast mining of rock salt in Saudi Arabia. Each hole showed the overburden depth and after penetrating a short way into the rock salt, an SPT was performed to estimate the overall thickness. In the background a rotary rig is core drilling at wider spacing to confirm the estimates. The Forager-55/1250 is being employed to quickly and efficiently provide large amounts of data over a wide area, with little support or consumables required. Drilling is normally just a two-man job, but a training session was in progress here. The standard rig is shown being used here, but a PROSPECTOR version is available with a light aluminium engine and a completely demountable shorter and lighter tripod, but similar capability. The PROSPECTOR version is suited to economical Placer (alluvial) sampling. link to PROSPECTOR version of the rig

SITE SOIL INVESTIGATION WORK Set up on a floating platform (pontoon), the Forager-55/1250 rig is shown being used for site soil investigation over water, in advance of a Civil Engineering project in Poland. 6-inch temporary casing is being used to support the holes, which were nominally 30 metres deep. The method allows the taking of both undisturbed (U100) and bulk samples. Standard Penetration Tests (SPTs) can also be performed at any required depth. An adjustment to the layout would allow the rig to drive piles. :   Pile details

Picture curtesy of:-  INGEO Sp. z.o.o., Gdynia, Poland   http://www.ingeo.com.pl

TOWING The rig, when folded, can easily be towed by a small car or pickup. The balance of the machine - with the weight of the tripod counterbalaced by the engine and winch - and weighing only about 450 Kg, means that it can be wheeled easily by hand between drilling sites. In extreme situations, the rig's own winch can be used to pull it into and out of a site or through streams. The rig can be dismantled into sections no more than 3 metres long, and is then canoe or raft portable. Shown here with a Lister-Petter diesel engine, with non kick-back crank handle starting, and direct Vee-belt drive. The PROSPECTOR version of the rig has an aluminium Yanmar engine whcih is about half the weight of the cast iron Lister-Petter.

FREE-FALL WINCH    The main component of this drilling system is the Consallen free-fall winch. The standard version is belt driven, from the engine and provides 1250 Kg (2750 lbs) of hoisting capability and 38 metres (125 ft) per minute of bare drum hoisting speed. The winch is clutchless, being based on an internal epicyclic gearbox, and is operated and controlled by two external band brakes. A foot pedal operates the drum brake and a hand lever controls a second brake, which causes the drum to reel in when applied. Relaxing the hoist lever allows the tool string to fall freely for maximum impact in the hole. The foot brake can be locked 'on' with simple device. Having no clutch, and using band brakes and an internal gearbox, no part of the winch is subjected to thrust loading. All band brake loads are balanced and provide no additional bearing loads. The design ensures long life and robusness. The design incorporates two safety features. The arrangement of the power train is such that either the engine will stall or the drive belts will slip in an attempt to exceed the design load. A second safety feature is provided that prevents damage to the winch in the event that the brake is applied while the drilling tools are in freefall. This consists of a soft strut, which bends upon overload. The brake is not incapacitated, but will slip immediately, untill the position (hand or foot) is changed. The soft strut is easily replaced without needing to dismantle anything. With a bent strut, the winch capacity is reduced, depending on the severity of the bend. NOTE that in its standard mechanically powered form the winch is not a lifting device, is only intended for use as a freefall winch in a cable-tool drilling context and not for any other lifting purpose. However, the hydraulically powered version can be arranged to provide a safe lifting capability, as may be required for handling pumps: see below.