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Placer and alluvial mining, measured downstream.

Placer gold, tin and gem gravels are worked in rivers and floodplains, often far from power and networks and often by small and artisanal operators. What matters is what leaves the site: sediment and turbidity in the river, sometimes mercury, the stability of settling ponds and the land handed back. Solar stations, LoRaWAN and satellite links make all of it measurable and shareable.

Industry

Mining

Measurements

6

Sources cited

6

1. Mining · Placer and alluvial mining

   A river that carries the evidence

   Placer mining washes gravel with river water and returns it, so the river carries the evidence of how a site is run. Many workings are small, remote and informal, and the people downstream live with the result. Measuring what leaves the site, openly, is the foundation of a licence to operate and of responsible sourcing.

2. What is measured

   Sediment, level, chemistry and rain

   Sondes measure turbidity, pH, conductivity and temperature upstream and downstream of the workings and at pond outlets. Level sensors gauge the river and the spillways, a rain gauge watches the catchment, and laboratory samples for mercury are taken where and when the continuous record shows they matter.

   Instruments

   Water-quality sondes · Level sensors · Rain gauge · Laboratory samples

3. The base node

   Stations that need no grid

   Each station is a sonde and a level sensor read by a battery LPWAN endpoint, with a small solar panel. The endpoint stamps and sends short readings to the gateway, which checks them against the upstream reference, signs them and keeps a local copy until the backhaul confirms delivery.

4. Radio and links

   LoRaWAN up the valley, satellite out

   One LoRaWAN gateway on high ground hears stations along the reach. Where a public network reaches the valley, a cellular modem carries the data; where none does, a LEO or satellite IoT terminal does. The choice comes from the survey, and the stations do not change if the backhaul does.

   Radio

   LoRaWAN · Satellite · Public cellular

5. How it works

   From a sonde to a shared record

   A sonde reports over SDI-12 to its endpoint, the endpoint sends over LoRaWAN to the gateway, and the gateway forwards over satellite to the governed record. There, each reading is compared with the upstream station, flagged for quality and published to the operator, the agency and, where agreed, the community.

6. From order to operation · Order

   Scope the reach and the permit

   The scope starts with the river: where the workings are, where the reference and compliance points must be, what the permit or the community agreement requires and whether mercury is part of the story. Nexus Observatory Inc. returns a station plan, the radio approach, the sampling programme and a price per reach.

   Plan a deployment

7. From order to operation · Survey

   Walk the river with the people who use it

   The crew walks the reach with the operator and, where agreed, with community monitors. It chooses stable sections for sondes and gauges, checks flood marks, finds high ground for the gateway, measures radio coverage and records every position with photos, coordinates and the landholder’s consent.

8. From order to operation · Permits

   Water, land and community agreements

   Stations in a river need the consent of the landholder and, often, of the water authority. Discharge monitoring follows the operator’s permit, and mercury sampling follows the national plan where one exists. Agreements say who may see which data before any station is installed.

9. From order to operation · Build

   Build stations that survive floods

   Sondes, level sensors and endpoints are assembled with their solar panels and batteries, configured and tested on the bench, then enrolled with their identities. Mounts are chosen for scour and debris, and every part is labelled so a local technician can swap it in the field.

   Open the Station Builder

10. From order to operation · Install

    Install in a low-water window

    Installation is planned for low water. The gateway and its backhaul go in first, then the upstream reference, the downstream compliance stations, pond outlets and the rain gauge. Every station is levelled to a benchmark and photographed for the record.

11. From order to operation · Commission

    Commission against samples

    Each station proves its identity, then its readings are compared with grab samples analysed by a laboratory and with a manual level reading. Alarm levels for turbidity come from the permit or the agreement, and a test alarm runs from the river to the operator’s phone.

12. From order to operation · Operate

    See the plume as it forms

    The console shows each station against the upstream reference, so a plume from a wash plant or a breached pond is visible as it forms. Alarms reach the operator and, where agreed, the agency and the community, with the data and the location attached.

13. From order to operation · Maintain

    Clean, calibrate and train locally

    Sondes foul in sediment-laden water, so cleaning and calibration follow a schedule driven by the data itself. Local technicians and community monitors are trained to do routine visits, and every visit updates the record that the next person works from.

    Book field services

14. Data products

    One river, several readers

    Operators see their discharge against the upstream reference and their permit; water authorities receive compliance series in their own system; communities see the agreed stations in their language; health agencies receive mercury results with their chain of custody. Rehabilitation maps show the land handed back, season by season.

    See the data products

15. Evidence

    Evidence for permits and responsible sourcing

    Station positions, calibrations, laboratory results and every alarm are kept as signed records. Discharge monitoring follows the operator’s permit, mercury work follows the Minamata Convention’s approach for artisanal gold, and data moves through OGC standards, so a buyer, an agency or a community can verify it independently.

    Drawn against

    Minamata Convention · 40 CFR Part 440 · WMO-No. 168

16. What you get

    Environmental and permit monitoring

    Emissions, water quality, noise and dust monitoring for permit conditions, with traceable calibration and evidence bundles. Delivered as managed service and data licence, for industrial operators, municipalities, regulators. Scale: Site to portfolio. Service levels are written as numbers you can measure on your own dashboard.

    Talk to sales

17. Next step

    Plan placer and alluvial mining with us

    Tell us the site, the measurements and the rules it answers to. We reply with a survey proposal, a design and a scope for placer and alluvial mining. An engineer replies with a survey proposal and a scope, and the plan grows from one site to the network you need, at your pace.

    Plan a deploymentOpen the Station BuilderOpen the Studio

01The place and its hazards

Where it runs, and what can go wrong.

Operating contextPlacer deposits concentrate heavy minerals in river gravels, terraces and floodplains. Operations range from dredges and excavator-and-wash-plant sites to small and artisanal workings. Water washes the gravel and returns to the river, so sediment and turbidity are the defining environmental measurements, and where mercury is used to amalgamate gold its release threatens people and rivers far downstream.

Hazards

• Turbidity and sediment plumes downstream of wash plants
• Mercury release where amalgamation is used
• Failure of settling ponds and small dams in floods
• Collapse of riverbanks and pit walls in loose gravels
• Flash floods reaching workings in the channel

02What must be measured

What, where, how often, and under which rules.

Each measurement names where it is taken, how often, and the public standard or regulation behind it. Numbers in the sources column open the cited source below.

03The observation stack

From one base unit to a network.

The same blocks at every scale: instruments and a base node, a site with its radio, a fleet run as one, and a network federated on the open protocol.

1. 01

   Base unit

   A solar water station: a sonde and a level sensor read by a battery LPWAN endpoint, or a small node with a satellite modem where no gateway reaches.

   Build a station →
2. 02

   Site

   A reach of river: an upstream reference station, downstream compliance stations, pond outlets and a rain gauge, with a LoRaWAN gateway on high ground.

   Plan a site →
3. 03

   Fleet

   Every lease and wash plant of an operator, or every operator in a district, measured the same way so that results compare.

   Managed offers →
4. 04

   Network

   Catchment agencies, operators and communities share one record of the river, each with the access their agreement gives them.

   The open protocol →

• 01Water quality sonde
• 02Water level gauge
• 03Compact weather station
• 04LPWAN endpoint
• 05LoRaWAN gateway
• 06LEO flat-panel terminal
• 07Solar array
• 08Pole

Radio and links

LoRaWAN

Small readings from many river points travel a long way to one gateway on a hill, from stations that run on batteries and small solar panels.

Radio and links

Satellite

LEO broadband or satellite IoT carries the gateway’s data where there is no cellular network in the valley.

Radio and links

Public cellular

Where a public network reaches the river, a cellular modem is the simplest backhaul.

Edge computeA small node at the gateway checks every reading against its upstream reference, flags plumes as they form and keeps a local copy, so a lost satellite pass never loses data.

PowerEvery station runs on solar and batteries sized for the cloudiest season; the gateway shares a solar skid on high ground, out of reach of floods.

04How it works

From the instrument to the product.

One observation’s path, tier by tier, with the interface on every link and a bill of materials below; then how the one node grows to a site, a fleet and federated networks.

05From order to operation

Every step, from the first call to a running site.

The same crew and the same record carry the work from scope to maintenance.

1. 01 Order

   Scope the reach and the permit

   The scope starts with the river: where the workings are, where the reference and compliance points must be, what the permit or the community agreement requires and whether mercury is part of the story. Nexus Observatory Inc. returns a station plan, the radio approach, the sampling programme and a price per reach.

2. 02 Survey

   Walk the river with the people who use it

   The crew walks the reach with the operator and, where agreed, with community monitors. It chooses stable sections for sondes and gauges, checks flood marks, finds high ground for the gateway, measures radio coverage and records every position with photos, coordinates and the landholder’s consent.

3. 03 Permits

   Water, land and community agreements

   Stations in a river need the consent of the landholder and, often, of the water authority. Discharge monitoring follows the operator’s permit, and mercury sampling follows the national plan where one exists. Agreements say who may see which data before any station is installed. 24

4. 04 Build

   Build stations that survive floods

   Sondes, level sensors and endpoints are assembled with their solar panels and batteries, configured and tested on the bench, then enrolled with their identities. Mounts are chosen for scour and debris, and every part is labelled so a local technician can swap it in the field.

5. 05 Install

   Install in a low-water window

   Installation is planned for low water. The gateway and its backhaul go in first, then the upstream reference, the downstream compliance stations, pond outlets and the rain gauge. Every station is levelled to a benchmark and photographed for the record.

6. 06 Commission

   Commission against samples

   Each station proves its identity, then its readings are compared with grab samples analysed by a laboratory and with a manual level reading. Alarm levels for turbidity come from the permit or the agreement, and a test alarm runs from the river to the operator’s phone.

7. 07 Operate

   See the plume as it forms

   The console shows each station against the upstream reference, so a plume from a wash plant or a breached pond is visible as it forms. Alarms reach the operator and, where agreed, the agency and the community, with the data and the location attached.

8. 08 Maintain

   Clean, calibrate and train locally

   Sondes foul in sediment-laden water, so cleaning and calibration follow a schedule driven by the data itself. Local technicians and community monitors are trained to do routine visits, and every visit updates the record that the next person works from.

06Data products and integration

What it delivers, to whom, and into which systems.

Data products

• Turbidity and sediment record against the upstream referenceOperators, water authorities, communities
• Discharge compliance reportsEnvironmental managers and regulators
• River level and flood alertsSite supervisors and downstream communities
• Mercury sampling results with their chain of custodyHealth and environmental agencies
• Disturbance and rehabilitation mapsLease holders, land agencies, rehabilitation funds

Integration

• Agency water information systemsSeries are exchanged through OGC SensorThings and the formats the agency’s hydrometric system accepts.
• Community dashboardsAn open view of agreed stations is published for downstream communities, in their language.
• GIS and lease recordsDisturbance maps are delivered as georeferenced layers alongside the lease boundaries.

Exchanged through OGC SensorThings API, LoRaWAN, WaterML 2.0.

07Questions buyers ask

Before you scope it.

Can small operators afford this?

Stations are compact and solar powered, and a district can share one gateway and one service. Programmes are often funded by agencies or buyers who want verified responsible sourcing.

Can communities take part?

Yes. Community monitors can host and read stations and see the agreed data. Their readings carry the same metadata and quality flags as every other source.

Do sensors measure mercury directly?

No. Mercury is measured from samples in a laboratory. The continuous record shows when and where to sample, and the results join the same record with their chain of custody.

What happens in a flood?

Stations and the gateway are sited and mounted for flood flows, and every station stores its data until the link returns.

08Resources

The sources behind this page.

Public standards, regulations and guidance, cited where they apply. Each applies only where its jurisdiction or scope does.

1. 140 CFR Part 440: Ore mining and dressing point source categoryUS Environmental Protection Agency (eCFR)
2. 2National Pollutant Discharge Elimination System (NPDES)US Environmental Protection Agency
3. 3Guide to Hydrological Practices (WMO-No. 168)World Meteorological Organization
4. 4Minamata Convention on Mercury (Article 7, artisanal and small-scale gold mining)United Nations Environment Programme
5. 5Guide to Instruments and Methods of Observation (WMO-No. 8)World Meteorological Organization
6. 6Copernicus Sentinel-2 optical missionEuropean Space Agency

09Related

Use cases and solutions.

10Mining: specialized fields

Other fields of this industry.

Bring us the site.

Plan a deployment, configure a station, model it in the Studio or talk to sales. The form names who receives your details.