There are two main elements that ARCA will develop for the AMi program: the carrier rocket, EcoRocket Heavy, and the AMi Cargo spacecraft that will be used for the actual mining activity.

EcoRocket Heavy Launcher

Before the fabrication of the EcoRocket Heavy, we developed the EcoRocket Demonstrator, a three-stage, reusable, small orbital rocket launcher build to serve as a technological demonstrator for the EcoRocket Heavy.
This rocket able to launch a payload of 10 kg into LEO, aims to demonstrate two main features: cost effectiveness and environment protection.
EcoRocket Heavy is an ecological, reusable, unprecedentedly low-cost rocket, able to launch 24 tones to LEO, that will be used by ARCA to launch the asteroid mining vehicles.
We think that the problem with the development of a heavy launcher is mainly the difficulty to fabricate and operate large structures. The infrastructure that is required to manipulate a fragile tank that is 10 m in diameter, tens of meters long and weights tens of tons is extremely demanding and it might represent an important portion of the cost.
We decided therefore that the EcoRocket Heavy is going to be made of small structures easy to manipulate.
EcoRocket Heavy will use the EcoRocket Demonstrator’s uprated first stage as a Propulsion Module (PM), which is an individual rocket in itself. Multiple PMs are strapped together to create a bigger, more capable structure, able to lift significantly more payload. So, EcoRocket Heavy has an unusual configuration for a rocket as it is wider than taller.
The transport is also simplified, the propulsion modules being carried by regular size tracks.
The third stage is placed around the payload and is made of two rows of propulsion modules, accounting for a total of 30 units. The second stage is wrapped around the third stage and is made of three rows of propulsion modules, accounting for a total of 90 units, while the first stage is made of seven rows of propulsion modules, accounting for a total of 420 units.
In total, EcoRocket Heavy has 540 propulsion modules.The EcoRocket Heavy has a maximum diameter of 34.5 m, a length of 28 m, an empty mass of 188 t. 
With a total launch mass, including the payload, of 5,443 t, and a take-off thrust of 12,600 tons, EcoRocket Heavy is the heaviest and has the highest thrust compared to any other vehicle ever built. It also promises the lowest cost/kg ever recorded.
More information on the EcoRocket Heavy, here:

AMi Cargo

The Asteroid Mining Spacecraft is a 20 metric tons to Low Earth Orbit (LEO) vehicle that will be used for reconnaissance missions to identify potential mining targets and for actual asteroid mining operations.
The spacecraft is made of three main sections: the Recoverable Capsule, the Service Module for the capsule that is housing the propulsion system and the interplanetary carrier that is housing the spacecraft's main propulsion system as well as the propellant tank and the solar panels that are providing the power for the main plasma electric-arc engine.

There are 384 m2 of solar panels generating 60 kW, distributed on eight surfaces that are articulated on an axis with the ship’s body. The electricity is used to power the Spacecraft’s arc-electric propulsion technology.
​The main propellant tank will house 17,000 litres of water used as propellant that will allow the main engine to run for 51 days 19 hours.
The vehicle has a return to Earth capability of up to 2,500 kg of precious metals, water, or other elements from the asteroids.
More information on the AMi Cargo, here: