The month-end argument at the scale house is the same one I hear on civil pads: the tickets do not match the pile, the millings look smaller than the haul, and somebody has to explain it to the owner by Friday.
You hire a drone pilot for stockpile volume when you need cubic yards on named piles — sand, aggregate, millings, dirt — without shutting the yard down for a ground topo. I fly this commercially from Springdale, Arkansas. The job is inventory, not a highlight reel of the crusher.
What stockpile volume actually is
You are hiring a mapping flight of the piles, not a site movie. The aircraft flies a grid over the yard or the pad. Photogrammetry builds a surface. Volume is the difference between that surface and a base you agreed to: the pad, last month's surface, or a toe you marked. A number without a named pile, a date, and a stated base is a conversation, not inventory.
Typical hires: a quarry or aggregate yard that needs month-end inventory by material; an earthwork GC that needs dirt, millings, or spoil before a pay app; a site super with a millings drop or a sand pile that keeps getting borrowed.
You are not replacing the surveyor on a pay-quantity unless the PO says control, checkpoints, and that use. Ask for the method. Do not accept a slogan about "survey grade" with no control plan behind it.
What you actually get
An ortho of the yard
The ortho is the picture of the piles, the bins, the scale, and the haul road so nobody argues which pile was which. Ask for a georeferenced GeoTIFF in the coordinate system the yard already uses, plus a web image for people who will never open GIS. Date and site name on the file.
A surface and a number per pile
The surface is a DSM or a dense point cloud of each pile. The operator draws the toe, or you hand them polygons that match your yard map. Volume comes out in cubic yards against the base you named. Ask for a table with pile name, cubic yards, date, and base used, plus the surface file and the polygons. If the toe moves in the drawing every month, the trend is fiction.
Do not ask the pilot to convert yards to tons unless you own the density. Moisture, compaction, and swell are yours. The aircraft measures space.
Cut/fill when the pile moved
Month over month, cut/fill on the same pile shows what left and what landed. Same base, same pile names, same coordinate system. If last month used the pad and this month used a floating toe, you measured two different ideas. Keep the scope on the piles. Site-wide cut/fill against a grading design is a different hire.
How often to fly
Month-end is the usual rhythm for a quarry or a materials yard. Fly after a large inbound or outbound if one haul would swing the books. Earthwork GCs often fly before a pay app, after a millings drop, or when spoil leaves the pad. Weekly is rarely worth it unless the yard is turning that fast.
Write the cadence and the weather slip. Rain and wind above the aircraft limit cancel a usable surface; the operator proposes the next slot before inventory close. Loaders on the pile during the grid put holes in the surface. Park them off, or accept a dirty number.
What this is not
Do not hire stockpile volume if what you want is a cinematic quarry video, a stamped topographic survey, or a photo log of the whole job. Those are different products.
Do not treat a drone volume as a truck-ticket audit by itself. Tickets are weight. The mesh is volume. They disagree when moisture, swell, or a dirty toe is in play. Use both. Inventory for a GC, quarry, or owner is commercial work. Part 107 applies. So does the COI your risk team asks for on any sub.
How to hire
Write the scope like an inventory operation, not like "come fly the yard."
Operator checklist
- Current FAA Part 107 Remote Pilot Certificate. Commercial flight in the U.S. requires it. Ask for the certificate number.
- Certificate of insurance. Many GCs and quarries ask for $1 million commercial general liability, additional insureds, plus aviation coverage. Use your risk team's minimums.
- Airspace plan. Controlled airspace means LAANC or an ATC path before takeoff. Confirm the operator files it. Need the law on Part 107 and airspace? dronelaws.us.
- Mapping experience on piles, not only stills. Ask for a sample volume table and a surface from a prior yard job.
- Method in writing: RTK/PPK, ground control, checkpoints, or a mix. If you will pay or bill from the number, say so on the PO. Operational inventory and pay-quantity are not the same bid.
Deliverable checklist
- Georeferenced ortho (GeoTIFF) plus a web image, dated, named with site and date.
- DSM or point cloud in the project or yard coordinate system.
- Volume table: pile name, cubic yards, base used, date.
- Toe polygons you can reuse next month.
- Optional one-page PDF for the inventory packet.
- Turnaround in writing. A common window is 24 to 48 hours from wheels-down.
- Who owns the files, and whether you can share them with the owner, the estimator, and the scale house.
The toe, the loader, and the pad
The weakest part of a stockpile number is almost never the flight. It is the base. Walk the operator through the pad, the bins, and which piles share a wall. Mark undercut faces if you know them. A steep millings pile will under-read if the camera cannot see the face.
Tell the yard: no loaders on the piles during the grid, people off the slopes, tarps off if you want the material counted. Get gate and radio contact. If you have existing control, share it. If you do not, say whether you expect RTK/PPK and a checkpoint conversation.
What to put in the email
Subject: Stockpile volume drone mapping, [yard or site], inventory date [date].
Body: Part 107 required. Named piles (list them). Materials if you track them — sand, aggregate, millings, dirt. Cubic yards against [pad / last survey / last flight]. Ortho, surface, volume table, reusable toe polygons. Coordinate system [State Plane or the yard's]. Cadence month-end or this date only. COI if we ask. Send certificate number and a sample volume packet from a prior yard.
Keep it short. The pilot who answers with pile names, a base, and a real turnaround is the one you want.
Find a pilot
Browse Part 107 pilots near the yard on Find a Drone Pilot. Ask for a sample stockpile packet, lock the pile list and the base before inventory close, and hire the operator directly. No broker in the middle, no commission on the job.
The pile is already there. Hire for the number you can stand on.