* Technology may make new mines profitable
* Industry in crisis, has capital constraints
* Sector battered by low prices, social unrest
BURGERSFORT, South Africa, May 16 (Reuters) - Technologies used to carve subways and clear landmines are being retooled to mechanise South Africa's platinum mines, where an unforgiving geology has stymied such efforts at a huge cost.
The technologies may make new mines profitable and could provide a lifeline for some loss-making shafts in a sector battered by low prices and social unrest, but there are limits.
Innovations include a 60-cm-high bulldozer built by private Croatian landmine clearance company Dok-ing that can reach narrow reefs, and a machine engineered by Atlas Copco unit Epiroc to replace blasting.
The stakes are high in the world's top producer of the metal: most of South Africa's platinum shafts are losing money, while the handful of mechanised ones are profitable.
Used for emissions-capping autocatalysts, the price of platinum remains pinned below $1,000 an ounce, less than half the lofty peaks it scaled a decade ago. Little upside is seen with diesel car sales falling.
An unpublished report by South Africa's Chamber of Mines says: "Under current price and cost forecasts, conventional (platinum) mining ceases to be economically viable in 2024."
This risks tens of thousands of jobs on South Africa's platinum belt, a flashpoint of social strife.
LANDMINES TO PLATINUM MINES
The South African platinum reef is generally too narrow and steep for machines to access, sparking a race to shrink machine size.
At Anglo American Platinum's Twickenham R&D mine, an operator with a videogame-type controller recently manoeuvred the Dok-ing bulldozer that sweeps away ore.
Dok-ing began by building robust dozers that cleared landmines - compact beasts with tank-like tracks.
Tom Sertic, managing director for Dok-ing Africa, said it caught the eye of Anglo engineers. In 2003, at Anglo's request, Dok-ing built an 83-cm-high dozer and has since cut the size.
The dozers' tank-like treads help to resolve a key mechanisation challenge: the inability of machines with traditional tyres to mine steep gradients.
"Most machines ... cannot work above 14 degrees because their wheels simply cannot generate power at such steep gradients," said Declan Vogt, a lecturer in mining automation at Britain's University of Exeter.
The Dok-ing dozer's design enables it to work on reefs at gradients of up to 22 degrees or more.
Amplats plans to use the equipment to boost the profitability of shafts at its Amandelbult and other mines - ironic, because it is a battery-run electric vehicle and Amplats has bet heavily on fuel cells in the EV revolution.
Lonmin Chief Executive Ben Magara told Reuters his company was using three of the dozers at its Saffy shaft.
But costs are a concern.
"The up-front capital is the challenge and given the constraints in the industry, that is not small," Magara said.
Bringing the technology to loss-making shafts also depends on how long they are expected to produce.
"It is a complicated process to switch to mechanisation. You need to cut jobs, bring in new skilled workers, set up workshops, and make other adjustments," said Johan Theron, spokesman for Impala Platinum.
Theron said Implats wanted to mechanise where it could but the time and investment would not be worthwhile in older shafts.
Another innovation is to dispense with blasting, allowing for continuous work as mines must be emptied for detonations, disrupting work.
At Twickenham, the Rapid Mine Development System (RMDS) designed by Epiroc churns the rock-face with a steel disk. Cutting technology has been deployed in coal mines for decades using mechanical picks, but this is the first used in a hard-rock platinum mine.
Walking through the tunnels, you see the difference.
The sides and the roof of the blasted area are jagged, presenting hazards including loose rocks. Where the cutter has been, everything is smoother, with just grooves - not unlike a subway, for which the technology was originally designed.
The RMDS also has a mechanical roof bolter - in conventional mines, a miner with a jackhammer-like device drills and inserts the bolts - and it carries the ore on a conveyer system.
MECHANISE OR DIE
"If you look at the bottom end of the cost curve, it is dominated by mechanised mines. Machines do the heavy lifting so productivity is significantly different," Northam Platinum Chief Executive Paul Dunne told Reuters. Northam's mechanised Booysendal mine is ramping up production.
Implats' annual results show its conventional Rustenburg operations last made a profit in 2014 and have since lost around 14 billion rand ($1.12 billion). By contrast, mechanised Two Rivers is Implats' lowest-cost operation.
Sibanye-Stillwater has acquired Amplats' labour-intensive Rustenburg mines and its mechanised Bathopele mine. The latter generates over half its platinum profit in South Africa.
Amplats, now firmly focused on mechanisation, paid a dividend this year for the first time since 2011, underscoring the benefits of its pivot from conventional mining.
($1 = 12.4963 rand) (Editing by Veronica Brown and Dale Hudson)