Guide: Spoil Heaps

Waste-mounds & spoil heaps

These are artificial hills made from the unwanted rock, Shale and tailings that come up with coal, metal ore, stone or clay when it is being mined or quarried. Because extractive industry is both deep and long-lived, single collieries or pits can generate tens of millions of cubic metres of spoil; pushed out by locomotive, conveyor or tippler wagon and dumped in successive layers, the piles quickly become a distinctive landform.

From the moment the first Neolithic miner prised nodules of flint out of chalk at Grimes Graves, humans have left piles of unwanted earth and stone beside every hole they dug. These discard mounds—whether waist-high humps of hand-shovelled spoil, or low ridges pushed aside by wooden waggons—are often the only surface traces of extractive episodes that left no standing buildings or other structures. Being able to “read” them is therefore essential background to any landscape study.

What exactly is a “spoil-heap”?

In archaeological terms it is any artificially accumulated mass of overburden or tailings that results directly from subsurface extraction—stone, ore, clay, pigment, salt or peat. Its form depends on three simple variables:

Variable	Controls	Typical archaeological signals
How the spoil was moved	basket, barrow, sledge, cart, rail-tub	tiplines, ramps, track ruts
Where it was tipped	edge of Shaft, lip of opencut, over cliff	cone, fan, linear bank
How long the pit stayed active	months, vs. years	number of layers, weathering horizons

 

Talus fan:  A small fan-shaped pile where loose spoil naturally slides down.

Cone tip:A pointed heap (like an anthill) formed when carts always dump in the same spot.

Rail-fan embankment: A long, gently curving bank created when tip-wagons move forward a little each time they unload.

Ganister: A very hard sandstone once quarried for lining industrial furnaces (mainly in South Yorkshire and Derbyshire). A “ganister pit” is simply the shallow quarry left by that work.

How mining activity changed over time

Stone Age and Bronze Age.

Early miners worked with antler picks, stone hammers and baskets. They tipped the waste right beside the hole. The result is a low, lumpy mound, usually no more than a metre or two high. You can still see these soft heaps around flint mines such as Grimes Graves in Norfolk.

Iron Age and Roman times.

By the Iron Age, people were using small carts or sledges pulled by people or animals. Spoil was thrown out along the line of the trench, creating a shallow ridge rather than a simple lump. The Romans went further: where water was handy, they sometimes washed whole hillsides with stored water to expose ore. The flushed-out rubble forms wide fans or gullies below the workings—good examples survive at the Roman gold mines of Las Médulas in Spain and at Dolaucothi in Wales.

Medieval period.

Water power, horse power and simple rails allowed deeper shafts and larger open cuts. Waste could be hauled a short way from the pit and dumped at a fixed point, load after load. Over decades this built a small cone-shaped hill, a familiar sight in many medieval lead and iron districts. In Brigantia country you may meet these pointed tips beside old lead hushes in Swaledale.

Early modern (before heavy industry).

From the sixteenth to the early nineteenth century, wooden or iron rails, bigger horse carts and the first steam engines let mines handle still more material. Spoil-heaps of this date are larger cones or long banks with wheel-ruts or rail beds still visible on their flanks.

Period / power source	Haul method	Spoil form	European examples
Neolithic–Bronze Age	Human power – baskets & hides	Small, irregular talus fans hugging the trench; sometimes rampart-like rings round vertical shafts	Flint mine spoil at Krzemionki (Poland); copper prospect scatters in the Austrian Tauern
Iron Age–Roman	Pack animals & two-wheeled tip carts	Elongated embankments flanking opencast fronts; spoil occasionally graded to form working platforms	Iron pits on the Weald (UK); hydraulic gold waste at Las Médulas (Spain)
Early-Medieval	Hand barrows, timber sledgeways	Low, lumpy hillocks beside bloomery shafts; often reused as later field lynchets	Early‐medieval iron “scoriae” mounds in Lorraine; lead hush spoil in the Pennines
High-Medieval–Tudor	Horse tramways, stackings over shaft mouths	Steeper conical tips up to 6–8 m as ore volumes rise; ragged trackways visible on LiDAR	Lead–silver tips in the Erzgebirge; coal “hillocks” of North Derbyshire
Early-Industrial (17 th – early 19 th c.)	Wooden or iron plate-way trucks, water-balance lifts	Regular “chevron” lines or rail-fan embankments; first signs of ash-rich black spoil	Charcoal-iron tips of Styria; bell-pit ridges across Durham and Northumberland

Why they matter

• Palimpsest recognition – Many sites re-occupy earlier extraction grounds (e.g., Bronze-Age Hushing scarps reused for iron-ore diggings), so recognising a low Iron-Age cart-tip against an earlier talus bank is key to correct phasing.
• Resource economy – Spoil chemistry (hammer-scale, Slag flecks, Ochre stains) tells us what ores or pigments local people valued and how they processed them.
• Territorial signals – In upland Swaledale or Nidderdale, linear tips often double as visual claims across valley floor grazing, tying industrial practice to land-holding strategies.

Tips for disentangling mixed mounds

Check the layering: prehistoric hand-dump tends to show thin, unsorted chalk or clay layer lenses; high-medieval cart tips build thicker, better-sorted layers.

Look for track imprints: twin ruts or sleeper-pits betray late horse-tram spoil routes slicing across an earlier tip.

Use LiDAR: subtle slope-breaks and zigzag haul ramps appear even under pasture, helping to separate conical “basket tips” from later rail fans.

Chronology of mining development

Date	Break-through	What it unlocked
c. 40 000 BCE	Ochre quarry at Lion Cavern in Eswatini (formerly Swaziland)	World’s earliest evidence of deliberate mineral extraction for pigment.
c. 3000 BCE	Timna (Israel), and Cypriot copper mines	Large-scale bronze metallurgy needs organised mining & smelting.
c. 100 CE	Roman hushing & hydraulics at Las Médulas (Spain)	Water power strips overburden & washes gold—first “industrial” hydraulics.
1627	Gunpowder blasting reaches German & Swedish metal mines	Rock-breaking no longer relies on firesetting; galleries drive faster. (en.wikipedia.org)
1712	Newcomen steam Engine pumps flooded shafts in England	Enables mines deeper than 30 m.
1770s	Cornish high-pressure engine (Watt → Trevithick)	Doubles efficiency; drives man-engines & winding gear. (cdn.cornishmining.org.uk)
1867	Dynamite patented by Nobel	A safer, more powerful explosive replaces black powder. (en.wikipedia.org)
1880s	Pneumatic rock drills	Mass tunnelling & hard-rock stopes.