Stump grinding on California Gully's old mine ground

Every suburb has its stumps, but stump grinding in California Gully has a twist most of Bendigo does not. Almost the whole suburb, from Eaglehawk Road back into the side streets, was mined, tunnelled and dumped on between 1852 and the 1920s, then built over with cottages that had their own rubbish pits, wells and outbuildings. What is under a stump here is rarely just clay, and this page starts with what a typical job looks like.

One morning's stump grinding in California Gully

Picture a weatherboard cottage on a block of about six hundred square metres a couple of streets back from Eaglehawk Road. A peppercorn came down last year and the stump, close to a metre across, is sitting in the middle of the back yard where the owner wants a new shed slab. The side gate is 900 millimetres wide, with a concrete path to the back door and the service line overhead.

We arrive with the narrow-access grinder, which fits through a standard gate, and lay boards over the path so the tracks do not mark the concrete. Before the machine starts we have already checked the Before You Dig plans for the block and walked the area with a probe, because a peppercorn stump on old mine ground can have anything under it. Guards go up around the stump to catch flying chips, the neighbour's windows get a sheet if they are close, and the cutting wheel works across the stump in passes, taking it down to around two to three hundred millimetres below the surface, deeper where a footing is going over it.

The surface roots are chased out as far as the owner wants for the slab, the pile of grindings is either shovelled into the trailer or raked back into the hole and topped with soil, and the yard is left level. A stump that size usually takes a morning, including set-up and clean-up. The hole settles a little over the next few months as the grindings break down, so we tell owners to over-fill it slightly if they are lawning over it.

What is actually under a California Gully stump

• Mullock and quartz rubble. Waste rock from the North Johnson and neighbouring mines was spread over the surrounding ground, and cottage blocks were levelled with it. Quartz is hard on grinder teeth and slows the job; we allow for it in the quote.
• Filled shafts and drives. Shafts near the primary school have been found subsiding and capped in recent years, and many more were backfilled with loose material a century ago. We keep the truck off anything that looks like fill, and roots that dive straight down into soft ground get left rather than chased.
• Cottage-era rubbish. Bricks, bottle glass, horseshoes and galvanised iron turn up under stumps on the old blocks. Metal in a stump breaks teeth, so we probe and scrape before grinding rather than finding out the hard way.
• Buried services. Old galvanised water pipes, clay sewer lines and, on the newer unit sites, gas and communications conduits run shallow through these yards. We check the plans, find meters and inspection points, and keep the wheel shallow near anything doubtful.
• Stony, shallow soil. Roots on box, ironbark and sugar gum stumps here run wide rather than deep, which is good news: most of the root mass is within reach of the grinder.

How the job runs

1. Quote from a photo or a visit. For a standard stump, a photo with a tape measure across it and a shot of the gate is often enough for a fixed price. Multiple stumps, unit-site clearances or anything near a known shaft, we come and look.
2. Services and ground check. Before You Dig enquiry lodged, meters and pits located, ground probed around the stump.
3. Access and protection. Boards on paths, guards around the work area, the neighbour warned if the stump is on the fence line.
4. Grind. Stump taken down in passes to the agreed depth, main surface roots ground out, deeper roots left to rot unless the area is being built on.
5. Grindings and finish. Grindings removed, or backfilled and topped with soil, or left as a mulch pile, whichever you choose. Site raked and swept.

Replanting, lawn or paving over a ground stump

Grindings are mostly wood chip and soil, and they rob nitrogen as they break down, so lawn sown straight onto them looks hungry for a season. Better to remove most of the grindings, backfill with soil and then seed. Paving or a slab can go over a ground stump once the area is compacted; for a shed footing we grind deeper and take the grindings away completely. Replanting a tree in the same hole is the one thing we discourage: the ground is full of decaying roots and a young tree struggles, so plant a metre or two to the side. If a screen is going in next, our hedge trimming in California Gully page covers which plants cope with the stony ground, and if the tree is still standing, tree removal in California Gully and grinding can be quoted as one visit.

Stump grinding in California Gully: common questions