How to make generated blocks minable?

My Question I generated a cave system with perlin noise, but I cant figure out how to make the generated blocks minable with a pickaxe. If anyone can help me that would be epic!

Sidenotes

Btw I know how to do it by inserting a script into each block but that would cause immense amounts of lag!

IMGUR Link

https://imgur.com/a/JpBdtbe

Generation Script -Generation.lua-

local mxs = 32
local mys = 128
local mzs = 32
local seed = math.random(0,1000000)
local ns = 20
local amp = 25
local ores = {'Coal','Iron','Silver','Sulfur'}
local colors = {Color3.new(0, 0, 0),Color3.new(0.72549, 0.72549, 0.72549),Color3.new(0.368627, 0.368627, 0.552941),Color3.new(1, 1, 0.498039)}
local deepness = {500,450,425,475}
local hp = {10,15,20,5}
local prices = {15,20,70,130}
--
for x = 0,mxs do
    for z = 0,mzs do
        for y = 0,mys do
            local xnoise = math.noise(y/ns,z/ns)*amp
            local ynoise = math.noise(x/ns,z/ns)*amp
            local znoise = math.noise(x/ns,y/ns)*amp
            --
            local density = xnoise + ynoise + znoise
            if density < 15 then
                local randomOre = math.random(1,20)
                if randomOre == 10 then
                    local chance = math.random(1,#ores)
                    part = Instance.new('Part',workspace.Terrain)
                    part.Name = chance
                    part.CFrame = CFrame.new(x*4,y*4,z*4)
                    local name = tonumber(part.Name)
                    if deepness[name] < part.Position.Y then part:Destroy() end
                    e = Instance.new('IntValue',part)
                    e.Name = hp[chance]
                    e.Value = hp[chance]
                    part.Color = colors[chance]
                    part.Anchored = true
                    part.Size = Vector3.new(4,4,4)
                    part.Material = Enum.Material.Neon

                else
                    part = Instance.new('Part',workspace.Terrain)
                    e = Instance.new('IntValue',part)
                    e.Name = 'Health'
                    e.Value = 5
                    part.Color = Color3.fromRGB(200, 200, 200)
                    part.Anchored = true
                    part.Size = Vector3.new(4,4,4)
                    part.CFrame = CFrame.new(x*4,y*4,z*4)
                    part.Name = e.Value
                    part.Material = Enum.Material.Slate
                    if part.Position.Y < 400 then
                        local rndm = math.random(1,3)
                        if rndm == 2 then
                            part.Color = Color3.fromRGB(150, 150, 150)
                            e.Value = 50
                            part.Name = e.Value
                        end
                    end
                    if part.Position.Y < 300 then
                        local rndm = math.random(1,3)
                        if rndm == 2 then
                        part.Color = Color3.fromRGB(125, 125, 125)
                        e.Value = 500
                        part.Name = e.Value
                        end
                    end
                    if part.Position.Y < 200 then
                        local rndm = math.random(1,3)
                        if rndm == 2 then
                        part.Color = Color3.fromRGB(118, 118, 118)
                        e.Value = 550
                        part.Name = e.Value
                        end
                    end
                    if part.Position.Y < 100 then
                        local rndm = math.random(1,3)
                        if rndm == 2 then
                        part.Color = Color3.fromRGB(77, 77, 77)
                        e.Value = 600
                        part.Name = e.Value
                        end
                    end
                    if part.Position.Y < 50 then
                        local rndm = math.random(1,3)
                        if rndm == 2 then
                        part.Color = Color3.fromRGB(84, 84, 84)
                        e.Value = 850
                        part.Name = e.Value
                        end
                    end
                end
            end
        end
    end
end
script.Disabled = true