A professional assassin seeks a space-efficient storage solution, preferably a single drilled hole to fit a career’s-worth of dead bodies.

I’m an experienced contract assassin who takes pride in putting people at the heart of my business. Not only do I work with my clients to provide bespoke assassinations to fit their needs and lifestyle, I also ensure every target has a comfortable termination followed by discreet and respectful waste solutions; I never settle for less than a burial.

After filling up my back garden with bodies, I started double-decking them, but soon I’ll need a new solution. I looked into setting up a cemetery and applied for planning permission but I’ve been stuck in administrative purgatory with my local authority for the past two years! I’m considering hiring a drilling rig for my back garden and digging until I have a deep enough hole to hide all of my biohazardous waste so I never have to fret about it again. Is this feasible?

Digging holes is a pillar of villainy! With your first hole, you will join the illustrious ranks of the likes of Cecil Rhodes with his magnificent ‘Big Hole’, the petroleum tsars drilling in brave defiance of do-gooders, and that fellow who experimented with dungeon form factors and accidentally invented the oubliette.

Drilling engineering is an entire discipline which cannot be summarised within the confines of this column (unlike soft disciplines such as ‘software’ ‘engineering’) so let’s set our sights on drilling at extreme depths. During the Cold War, Soviet scientists experimented with drilling as deep as possible into the Earth’s crust; the Kola Superdeep Borehole near the Norwegian border reached the depth of 12km before being abandoned. The world’s most top-hole hole, though, is the O-5RD well in the Okhotsk Sea, which reached 15km in 2017. But while the O-5RD well is the noodliest (longest) hole in the world, it is not deeper than the Kola Superdeep Borehole because it is not vertical.

Simply put: the deeper you thrust, the harder it gets. By the time the Kola drill bit reached 12km, the rock temperature was twice as toasty as scientists predicted at 180°C. Under these conditions, equipment begins deforming and drilling fluid vanishes. Drilling fluid circulates from the surface to the drill bit and back, cleaning away cuttings and removing heat. At these temperatures, it just boils off. The scientists found that temperature increases proportionally with depth; at 15km, for instance, temperatures would be around 300°C and the drill bit would be as much use as a toothpick. Add in the challenges of greater pressure, greater resistance, and friction rubbing away the outer part of the drill bit as it descends (causing tapering of the hole) and it becomes unfeasible to dig deeper than 12km. This is why drilling engineers developed technology for exercising amazing control over drill bits, so we can keep drilling without descending so close to Hades that equipment melts.

If 12km is the deepest we can dig without expensive technological innovation, let’s consider if it’s possible to store a career’s worth of human bodies (or shall we say ‘commercial waste units’?) in a single hole. The least space-efficient technique is simple stacking; the average unit is 1.65m, but if you stick one unit’s feet on the previous unit’s shoulders, each uses 1.4m of depth. So, you can store 0.71 units/m, right? Yes, but only if you use a drill bit with a diameter larger than that of the average person, such as the ridiculous 1.14m-diameter bit commissioned by Hess Corporation for use in the Danish North Sea. If I lived next door, I’d certainly tut loudly at your drill while I was hanging my laundry!

A smarter way of working would be to pop your commercial waste units in an industrial meat blender and pour them down your hole. The average unit has a mass of 62kg and (with the same density as water) a volume of 0.062m3. If you dig your hole with a drill bit like that used for the Kola Superdeep Borehole (0.23m diameter) you could fit 0.70 units/m.

A genius lurking on StackExchange suggested that human bodies – sorry! commercial waste units – could be further compacted through dehydration, essentially turning them into a 5 per cent water ‘meat and bone meal’. The typical unit is 60 per cent water, so a dehydrated unit would be 45 per cent its original mass (28kg). Meat and bone meals have a density of 720kg/m3, so a dehydrated human would take up just 0.039m3. Using the 0.23m-diameter bit, you could fit 1.08 blended and dehydrated units for every metre you descend!

So, how deep a hole would you need to dig in order to never have to worry about waste management again? As an upper bound let’s say you’re 25 and intend to work until 70, with one assignment per month: 540 units in total*. With the 0.23m drill bit, you’d need to dig just 0.5km into the ground to fill it with a career’s worth of blended and dehydrated human corpses! Easy! Even if you wanted to prepare for the possibility that your business grew very large by digging as far as you can, you’d still be able to fit around 13,000 bodies in that single 12km-deep hole. Using the gigantic 1.14m-diameter drill bit, you could fit 314,000. And if that still isn’t enough... I applaud your ambition as an entrepreneur!

PS: Have you ever considered a pie shop?

*Of course, over long periods of time the units at the bottom will skeletonise and be crushed by the pressure of those on top, which would make room for even more.

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