Richard Timbs
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Born 2nd December 1971
Recently nominated for induction in the Goldfields Miners and Prospectors Hall of Fame, Richard Timbs pioneered an innovative underground development 'cut' during the early 2000's while working at the Kundana Gold Mine, located just outside the city limits of Kalgoorlie, Australia.
A 'cut' is a sequence or pattern of drilled holes emplaced into a horizontal underground rockface, which are subsequently charged with precisely timed explosive charges. When 'Fired', the rockface is fragmented to a desired depth and profile according to the pattern used to drill the holes. The purpose of taking a cut is to advance an underground development excavation - typically a decline, incline, crosscut or drive.
The cut in question came to be developed in response to over-target advance rates encountered in ore driving in the typically massive quartz orebodies encountered in the Kundana ore zone and other Kalgoorlie underground operations. Over-target advance rates can be detrimental in the development of an underground operation, as the whole extraction sequence can be significantly affected. Employing this cut has become a useful tool for advance rate control by underground miners throughout the Goldfields area.
Known as the 'Freeze Cut', it employed a radical departure from conventional drill and blast methodology. Reamer holes, which are typically left uncharged in order to provide a free-face for the gradual opening up of a conventional Burncut were reduced from a normal number of four, down to a single central reamer. The 'Box and Diamond' drill pattern placed around the central reamers of a typical burncut were altered to resemble a 'Shoebox' (the design of which was borrowed from the obsolete 'Letterbox' cut)- a rectangular pattern using only six holes, bored on slightly inclining and declining angles so as to produce a fly-rock fragmentation effect similar to that of the now seldom used Wedgecut.
Easer holes were omitted almost entirely from the pattern, and the usual number of perimeter stripping holes was halved. Lifter holes at the foot of the face were double charged, which prevented the need for drilling and charging unnecessary knee holes.
The timing sequence of the explosive charges was altered too. Instead of using all 15 available nonel detonator delays, only eight were required as both the central wedge-shaped 'shoebox' and the perimeter holes were all fired at once at the beginning of the cut sequence, using #1 delay detonators.
The result of employing the 'Freeze Cut' on every second development cut was to successfully slow and control advance rates.
Other contributions to the Australian underground mining industry during his career have included alternative methods of underground tele-remote loader abandonment (first implemented on Toro-151 underground loaders and subsequently now being used with success on machinery as large as the Elphinstone R2900 series loaders), and a different method of clearing topsoil and low-lying flora from around the edges of mine haul roads using long sections of poly-pipe found in day to day use at most mining operations.
