Induced Polarisation Survey Cost: Per Line-km Ranges

An induced polarisation (IP) survey on public filings costs from about C$2,000 to about C$9,750 per line-kilometre, and the spread comes mostly from scope, not from the instrument. In three British Columbia assessment reports, 12 km of pole-dipole lines cost C$23,876 in 2015, 18 km cost C$89,770 in 2007–08, and 11.5 km of deeper, modelled lines cost C$112,132 in 2012. This page lays out those numbers, what moves them, what IP can and cannot find, and a calculator for your own programme.

IP is a ground geophysical method. It pushes a controlled current into the rock through electrodes, switches it off, and measures how the voltage fades. Rock that holds a charge, such as rock with finely disseminated metal sulphides, fades slowly. That delayed signal is called chargeability, and it is reported in milliseconds or in millivolts per volt (a 2024 review of electrical methods gives both units, and credits Conrad Schlumberger with developing the method in the 1920s: arXiv review of electrical and seismic refraction methods).

Induced polarisation survey cost per line-km: what filed reports show

Public price lists for IP are rare, because contractors quote each job. The most reliable numbers are the ones explorers have to file with a regulator. The British Columbia Geological Survey holds thousands of assessment reports, and each states the work done and what it cost. Three of them give the line-kilometres and a total cost for an IP survey.

Chart

Reported IP cost per line-km

Three BC surveys, C$ per line-km: reported cost divided by line length (scope differs by filing)

The Gnawed Mountain survey (fieldwork 27 April to 2 May 2015, near Logan Lake) covered about 12 km of lines using a pole-dipole array with a 100 m dipole. The report states a total of C$23,876.24, or about C$1,990 per line-km (BC assessment report 35646).

The Hit property survey near Aspen Grove (fieldwork 16 November to 6 December 2007, report dated March 2008) covered about 18 km of pole-dipole lines with 12.5, 25 and 90 m dipoles. The contractor did line establishment and IP on a daily basis, mobilisation and reporting were extra, and the stated total cost of services was C$89,770.16, or about C$4,990 per line-km (BC assessment report 29781b).

The Copau survey (2012) covered 10 lines and about 11.5 km. It used a high-resolution full-waveform system with a 3.6 kW transmitter, eight receiver channels and more than 100 electrodes, and the data were inverted into depth slices from 55 m to 455 m. The filing lists a project cost of C$112,131.72, or about C$9,750 per line-km (BC assessment report 33292).

These are Canadian filings from three different years, so inflation alone explains part of the gap. Amounts are dollars as reported in the BC filings (Canadian assessment reports). The Hit total leaves out mobilisation and reporting, and the Copau figure is the project cost including support, so the three are not like for like. Treat them as examples of how wide the range is, not as a rate card. The 2009 talk below gives a second angle, a price per area instead of per line.

Per-kilometre figures were calculated by dividing each reported total by the reported line length. The 3D talk, by Steve Collins at a 2009 SMEDG and AIG symposium, put a 3D IP survey at about 7,000 for the field work plus about 5,000 for gridding, modelling, plotting and reporting, per square kilometre (Collins, 3D Induced Polarisation, SMEDG–AIG 2009). The slides do not state the currency.

What drives the price of an IP survey

Four things move the bill more than the brand of receiver.

Chart

3D IP cost per square kilometre

Dollars per km2, currency not stated in the talk

• Line establishment and access. Cutting or flagging lines, moving camps and carrying cable through rough ground all cost crew days. In the Hit report, line establishment was billed with the IP itself.
• Array and dipole size. A larger dipole reaches deeper but gives a coarser picture. The Hit survey used three dipole sizes on different lines, and the Gnawed Mountain survey read separations from 0.5 to 19.5 on a 100 m dipole.
• Mobilisation and standby. Mobilisation was a separate line item in the Gnawed Mountain and Hit reports, and at Gnawed Mountain only C$1,250 was charged to the project because mobilisation was split with another job.
• Modelling and reporting. Inversion is the step that turns raw readings into a model of the ground. The Hit filing states that mobilisation and reporting were extra to the daily rate, so ask what a quote includes.

Ground conditions matter too. In the Paterson Province of Western Australia, sand dunes made it hard to push current into the ground, and a thin conductive layer under the sand was harder still. The crew switched from a dipole-dipole array to a pole-dipole array to raise signal (Prakash, Enright and Angus, AEGC 2018).

Budget your own IP survey

Use the calculator below to turn an area and a line spacing into line-kilometres and a total. Tighter spacing means more lines: a 4 km² block at 200 m spacing needs about 20 line-km, and at 100 m spacing about 40.

Chart

Total cost against line length

Each point is one filed survey

How an IP survey works, step by step

An IP survey is laid out as lines across the area, and the crew repeats the same measurement at each station along each line.

Infographic

An IP survey in 5 steps

1. 1Lay the lineFlag the line and lay cable with electrodes at fixed spacing.
2. 2Inject currentA transmitter drives current into the ground in on-off cycles.
3. 3Read the voltageReceivers record the voltage and its decay after switch-off.
4. 4Widen the spacingLarger separations sample deeper rock.
5. 5InvertSoftware builds a chargeability and resistivity model.

1. Lay the line. The crew flags a line and lays cable with electrodes at fixed spacing. At Copau, twelve to twenty-six 50 m cables formed a receiver cable of 0.6 to 1.3 km.
2. Inject current. A transmitter drives current through two electrodes. At Copau the standard cycle was 2 seconds on and 2 seconds off.
3. Read the voltage. Receivers record the voltage between other electrode pairs while the current is on, and the decay after it switches off.
4. Repeat at larger separations. Wider spacing between current and receiver electrodes samples deeper rock. The result is a pseudosection, a map of apparent values, not a true cross-section.
5. Invert. Software turns the apparent values into a model of chargeability and resistivity with depth. The Copau report cautions that parts of an inversion that the data do not constrain can produce artefacts.

There are three common ways to read the signal. Time-domain IP measures the voltage as it decays after the current stops. Frequency-domain IP sends alternating current at different frequencies and measures the phase shift. Spectral IP uses many frequencies to describe the full response (overview of time-domain, frequency-domain and spectral IP).

Which array: a quick guide from the reports

What induced polarisation finds, and what it can mistake

IP is best at finding disseminated sulphide, meaning small grains of sulphide spread through the rock rather than massed in a vein. In porphyry copper systems the ore often sits inside a halo of pyrite, which is easy for IP to map. A 1970 survey at the Ashnola porphyry property in British Columbia found a large horseshoe-shaped IP anomaly caused mainly by disseminated pyrite, estimated at 2 to more than 6 percent by volume. The author put the highest-priority target on the inner 10 to 20 millisecond range of the halo, where copper and molybdenum mineralisation showed near an unpyritised core (BC assessment report 02545).

The same filing notes that part of the polarisation was of a membrane type, probably from clay minerals and sericite. This is the central warning for anyone reading an IP map. A chargeability high is not proof of ore. The Copau report lists other possible sources: clay, platy alteration minerals such as serpentine, talc and sericite, oxides such as magnetite, pyrolusite and cassiterite, and graphite. The 2024 review makes the same point, that separating sulphides from clays and graphite needs other data.

A USGS study of a tungsten deposit in Saudi Arabia likewise found chargeability rising with sulphide content in granite samples (USGS Open-File Report 83-449). Pair IP with resistivity, which the same survey measures at the same time. In the Ashnola filing, the correlation between chargeability and resistivity was described as extremely high, and the author tied the pattern to three things: rock type, moisture and sulphide content.

What IP struggles with

• Poorly conducting ground at the surface. Dry sand and bedrock with high contact resistance make it hard to inject current, as the Paterson example shows.
• Non-sulphide ore. If the valuable mineral does not polarise, IP may see nothing. Ask a geophysicist whether your deposit type will polarise before you pay for a survey.
• Resolution at depth. Collins told the 2009 symposium that all IP has poor resolution that drops sharply with depth, and that models are coarse and ambiguous, plausible solutions rather than answers.

How deep does IP see?

Depth depends on the array, the spacing and the ground. The numbers in filed reports are more modest than the claims in many sales sheets. Copau reports reliable IP and resistivity data to depths exceeding 400 m under average conditions, with 500 m quite common. Collins described 3D IP as mapping the distribution of metallic grains, within reason, to about 500 m. The 1970 Ashnola survey, with a wide Wenner array, reached about 500 to 600 ft, or roughly 150 to 180 m.

Going far deeper takes a different set-up. The SEEMS DEEP project in Europe used a large 3D transmitter and receiver spread over 200 km² to reach beyond 1.5 km depth, with signals recorded at offsets up to 13 km (SEEMS DEEP project paper on deep ground electrical and electromagnetic methods). That is a research-scale layout, not a standard exploration quote.

2D lines versus 3D

Collins argued that 3D IP became cheaper once multichannel receivers got cheap and automatic 3D modelling software arrived around the year 2000. He said 3D can beat 2D on cost if done properly, with slightly better near-surface resolution and deeper penetration, but is harder in the field, because the best number of receiver points is a balance between data volume and the difficulty of keeping the array working. He recalled one survey where cattle ate up to four cables a day.

An IP anomaly that was drilled: the Paterson Province result

A published case from Western Australia shows how IP is used to rank targets and what happens when it is tested. Rio Tinto Exploration and Antipa Minerals explored more than 400 km² for disseminated and massive copper sulphide systems beneath 40 to 120 m of transported cover. They chose dipole-dipole and pole-dipole IP as a cost-effective way to rank 16 target areas. A 127 line-km survey in 2016 flagged multiple chargeability anomalies, and eight were picked for drilling.

At the known Magnum deposit, a proof-of-concept line showed a chargeable response about twice the background level. At the Blue Steel target, five reverse-circulation holes (1,004 m) and one diamond hole (661 m) were drilled. At 517 m the diamond hole cut a 19 m interval (11 m true width) of pyrrhotite-bearing magnetic gabbro with slightly anomalous copper, lead, zinc and tungsten. Core measurements showed the sulphur in the Blue Steel holes was too low on its own to explain the surface IP response, so the team went back to forward modelling to test other explanations (same AEGC 2018 paper).

The lesson is practical. An IP anomaly gives a drill target, and the drilling and core tests tell you whether the cause is economic. Budget for the modelling and rock-property work that follows the survey, not only the field days.

Where satellite screening fits before the IP crew

IP is a ground method, so it only covers the lines you pay for. Satellite imagery cannot replace it, but it can help decide where to put those lines. Mapping alteration, iron staining and structure from space can narrow a large licence to a smaller block before a crew is mobilised. Farmonaut produces satellite mineral detection reports from a licence boundary supplied as a KML, KMZ or polygon file, and the results are exploration targets, not a resource estimate. For a first season, see the sequencing guide on induced polarization survey sequencing for a first season.

If you are exploring a porphyry belt, the notes on Golden Triangle exploration in British Columbia cover the ice and access problems in that region. Budgets are tied to spending trends, which Canadian exploration spending data tracks. You can also ask about satellite-based mineral detection for your area, or send details through the mining query form.

▶ Farmonaut video: what AI in mineral exploration does, where it fails and how to check a claim. · 4:37

How to compare IP quotes from contractors

Ask every contractor to price the same specification, then compare line by line.

• Line-kilometres, line spacing and station spacing.
• Array type, dipole length and the maximum separation.
• Day rate, crew size and who supplies the vehicle and fuel.
• Mobilisation, demobilisation and standby for weather.
• Line cutting or flagging, and GPS and elevation control.
• Inversion: 2D or 3D, which software, and whether depth slices are in the price.
• Report, data files and raw data ownership.

Keep the raw readings, the inversion files and the maps together with your samples and drill logs. A mineral management system that holds all of it in one place makes it easier to compare an IP model with later drilling.

▶ Farmonaut video: keeping maps, samples and targets in one place. · 3:21

Related reading on this site: Drone Mapping Cost per Acre: Mine Survey Prices.

We cover a connected topic in PDC Drill Bit Price: Chart, Ranges and Cost per Metre.

Frequently asked questions

How much does an induced polarisation survey cost?

Filed British Columbia reports give about C$1,990, C$4,990 and C$9,750 per line-km for surveys in 2015, 2007–08 and 2012. A 2009 symposium talk gave about 12,000 dollars per square kilometre for 3D IP including modelling and reporting. Quotes depend on scope, so request several.

What does IP measure?

It measures how well rock stores and releases electrical charge after a current is switched off. The quantity is chargeability, in milliseconds or millivolts per volt.

What is the difference between IP and resistivity?

Resistivity measures how easily current flows through rock. IP measures the delayed voltage after the current stops. Surveys usually record both at once, and the pair is read together.

Which minerals can IP find?

It targets rock with disseminated sulphide minerals, which in the cases above includes a copper porphyry (Ashnola) and a copper-gold project (Paterson). It can also respond to clay, graphite and some oxides, so a response needs a geological explanation.

How deep can an IP survey see?

Filed examples reach about 150 m (Ashnola, 1970) to 455 m (Copau depth slices). The Copau contractor states reliable data below 400 m under average conditions, with 500 m quite common. Special large-spread projects have reached beyond 1.5 km.

What is chargeability?

Chargeability is the strength of the delayed voltage response compared with the voltage while the current was on. Higher values often mean more sulphide, but not always.

Is 3D IP better than 2D IP?

It maps complex ground better and can cost less per area, according to a 2009 talk, but it needs more careful field logistics and still has coarse resolution at depth.

How is time-domain IP different from frequency-domain IP?

Time-domain IP records the voltage decay after current stops. Frequency-domain IP uses alternating current at different frequencies. Spectral IP measures many frequencies to describe the full response.

Can a satellite survey replace an IP survey?

No. A satellite survey screens large areas for alteration and structure and helps place the ground lines. It does not measure chargeability under the ground.

How many line-kilometres do I need?

Line-km equals area in square kilometres times 1,000, divided by line spacing in metres. For example, 4 km² at 200 m spacing is 20 line-km. Use the calculator on this page.